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A Plantsmans Observations on the Genus

Hydrangea

The hydrangea family, Hydrangeaceae, is a respectable conglomeration of

shrubs, vines and herbaceous perennials resulting from a recent extraction

from a behemoth institution known as the Saxifragaceae. The herbaceous

components, in the respective genera of Cardiandra and Deinantheproffer

ornamental species for cultivation although it is the woody taxa of shrubs

and lianas of this family, in the genera Hydrangea, Deutzia, Philadelphus,

Platycraterand Schizophragma, that are by far the most familiar.Other than the exceptions of Hydrangea paniculata and H. quercifolia, the

prototypical hydrangea inflorescence is a corymb; a rounded disc of numerous

small, fertile flowers that possess insignificant sepals and four or five small

often white, pink or blue petals. This cluster of utility is surrounded by the

advertising agency of sterile florets, or ray flowers, that provide the stuff of

ornament. The ovaries are, as a rule, inferior (i.e., enclosed in the receptacle),

while the dehiscent capsules, sometimes in the shape of a Grecian water jar,

gave rise to the genus name; hydro, water and angeion, a vessel. The foliage is,

without exception, arranged in pairs.

This floral strategy of sacrificing the fertility of a few flowers to provoke

a bit of curiosity by commuting pollinators has co-evolved in other non-

related groups, most notably in the genus Viburnum. Thus, it would not

come as a complete surprise to those who have grown a double-file viburnum,

Viburnum plicatum, that the second Asiatic hydrangea to be noted by Western

botanists (in Japan, in 1777) was named Viburnum serratum. That nascent

nomenclatural error commemorates what would become a long and

complicated excursion into a field plethoric with taxonomic landmines.

The first hydrangea described from Asia, also in 1777 by Thunberg while

in Japan, was actually a mophead or Hortensia cultivar, with the bulk of its

fertile flowers clustered into heads of embellished yet mostly sterile florets

(see under H. macrophyllafor the convoluted genesis of Hortensia). Having

Daniel J. Hinkley, Heronswood Nursery, 7530 288th N.E., Kingston, WA, USA, 98346,

heron@silverlink.net

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never encountered such a lovely creature before, it is understandable that

Thunberg christened this Viburnum macrophyllum. It is important to note

that this type of hydrangea flower mutation is different from a doubling or

trebling of the sepal numbers in each ray flower, which results in rose-likeflorets surrounding the central core of usually fertile florets.

I consider that the confusing taxonomy of the hydrangeas that exists to

this day can be ascribed to a quartet of unfortunate circumstances. First,

much of the first named material, including Thunbergs Viburnum

macrophyllum, was based on clonal selections with no botanical standing.

Second, many Hydrangeaspecies have immense geographical ranges and the

natural, often significant variation found within each taxon was always

problematic, even in the relatively few cases when live material was readily

accessible for study. Remote and politically insular hotspots of Hydrangea

speciation (i.e., Japan and China), have not until recently offered much useful

data. Third, although Elizabeth McClintocks highly regarded monograph

(McClintock, 1957) remains the most comprehensive to date, it is fair to

point out that many of her astute observations were made in spite of a

paucity of oven-dried herbarium specimens. The fourth contributors to the

confusion have been nurserymen and lay authors, in the midst of whom Ifind myself, who have simply taken matters into their own hands, laying low

in great sweeps the systematists attempts to provide a robust grip on the

genus.

In this paper, I will attempt to place my personal observations of species

in the wild and those of known provenance that I have grown within the

broader academic context provided by McClintock. I have purposely avoided

the minefield of the complex of H. macrophyllaand H. serratacultivars, butI have discussed forms of numerous species, which I feel are important. I

leave the taxonomy to my more academic brethren hoping that they can

solve the riddles of this remarkable genus of plants, many of which are not

at all well known to horticulturists

Section Hydrangea

This section contains the deciduous members of the genus, including the

vines, and distinguishes them from the much lesser known, evergreen and

primarily southern hemispheran taxa, which are placed in Section Cornidia.

Both sections are divided further into subsections.

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Subsection 1 Americanae

The two North American species of Hydrangeahave achieved more than a

modicum of acceptance in Western horticulture. They were recognized by

native Americans for their curative properties and used by the Cherokeesand early American settlers for the treatment of calculus. They contain the

cyanogenic glycoside, hydrangin, although ingestion of raw hydrangea

vegetation does not seem to result in the typical clinical signs of cyanide

poisoning.

Hydrangea arborescensL. occurs along the eastern coast of the USA from

Florida to New York and west/southwest to Iowa and Louisiana, and is often

found growing under exceptionally shaded conditions. It is a deciduous shrubrising to 3m (10 feet) in height carrying ovate, smart, green leaves of a papery

texture. The mostly fertile, dingy white flowers of the northern populations

are hardly awe-inspiring in their pure state, but at least two selections have

considerable hardiness as well as frilly heads of sterile flowers. Hydrangea

arborescensGrandiflora and the more compact H. arborescensAnnabelle each

begin flowering in June with tasteful tones of lime green, ripening to pure

white, and changing later to verdant tones. The former was the first hydrangea

that I grew as a young gardener in Michigans frigid USDA Zone 4 interior,

where its somewhat sloppy growth was overlooked through my innocent

eyes of ignorance. The somewhat stronger stemmed, later blossoming

Annabelle, with flower heads to 30cm (12 inches) across, was selected at the

University of Illinois by J.C. McDaniel. It has justifiably superceded

Grandiflora in commerce, though I still find both exceptional contributors

to my mixed borders in USDA Zone 8.

In the southern Appalachians, the brilliant white indumentum on the foliageundersurface of H.arborescenssubsp. radiata(Walter) McClintock (Figure 1)

makes up for its lackluster floral display. It looks best growing atop

embankments or retaining walls. It remains one of my favorite hydrangeas

and deserves much greater recognition.

Hydrangea arborescenssubsp. discolor(Ser.) McClintock is poorly represented

in cultivation. It is best known as its cultivar Sterilis, which has frosty

heads comprised of mostly sterile florets. In June of 2003, I observedpopulations of this taxon at 2000-3500 in elevation near Asheville, N.C.

together with numerous individuals of H. arborescenssubsp. arborescens, i.e.

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without the grayish tomentum found on H. arborescenssubsp. discolor. Sterile

florets may or may not be present.

The oak-leaf hydrangea, Hydrangea quercifoliaBartram had a prolonged rise

to favor among North American horticulturists in those USDA Zone 5-9landscapes where it can be grown. Dr. Michael Dirr is probably responsible

for much of this interest, due to his selection work at the University of

Georgia. Though one of only two Hydrangea species that possess flowers

born in panicles rather than corymbs, it is the foliage of H. quercifolia that

sets it aside. Very leathery in texture, the boldly lobed and jagged-edged

leaves to 20cm (8 inches) in length do indeed resemble those of a red oak

and develop intense and prolonged tones of glossy burgundy in autumn. I

have seen this Gulf State native growing in Mississippi in semi-shaded sites

with more than adequate water, though in cultivation it appears to tolerate a

great deal of drought when established. Though Dirr recommends always

providing this species some protection from full sun, this does not seem

necessary in the Pacific Northwest where it becomes annoyingly rangy if

grown in too much shade, with leaves that fail to develop autumn tones or

abscise uniformly.

Subsection 2 Asperae

The subsection Asperae has outstanding ornamental potential, but it

contains many barriers and pitfalls in proper classification.

Hydrangea sikokianaMaxim. (Figure 2) is shockingly scarce in cultivation

considering its clearly handsome foliage and large white lacecaps to 30cm

(12 inches) across. I first observed it in the autumn of 1997 while in the

moist, cool highlands of Central Honshu on the Kii Peninsula with colleaguesBleddyn and Sue Wynn-Jones and Darrell Probst, the Epimediumspecialist.

It was on that particular day that I became aware of the enormous diversity

of the Hydrangeaceae on the Japanese archipelago. I could count no fewer

than eight hydrangea species or their close relatives without altering my

position. Among the group, growing on the shore of a rapidly moving

mountain stream was a tall shrub with large felted, light textured, jagged

edged leaves that appeared superficially similar to those of H. quercifolia. As

we had spent longer a week on Shikoku Island specifically searching for this

species without success, and were nearing the end of a second rainy, cool

autumn day, I was certain I had found what we sought. The moment of

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recognition was accompanied by that rarified charge of electricity that such

experiences are known to bring. From seed collected at that time, we were

able to re-introduce H. sikokiana into cultivation in North America and

Europe, but we have received few reports as to how it has fared. It is provingto be a distinctive, mid to late summer blossoming addition to our cool,

shaded woodland.

Hydrangea involucrataSieb. (Figure 3) was not among the species that we

saw on the Kii Peninsula on that particular day, although I had encountered

it on numerous occasions during prior travels in Japan, most notably in 1995

along the coastal forests of the Chiba Peninsula south of Tokyo. As its

specific epithet implies, H. involucratasets itself aside from all other species

in Section Hydrangea by possessing involucral bracts that enclose its plump,

rounded flower buds before opening. The bracts dehisce as the flattened

corymbs of lavender blue fertile flowers, surrounded by creamy white ray

flowers, open. The ovate foliage to 13cm (5 inches) in length is held along

stems to 3m (10 feet) in height. There are several forms in cultivation that

possess an aberrant doubling of the sepals in the ray flowers, in particular

the lovely cultivar Hortensis, which also surrenders a greater number of its

fertile florets to the cause of ornament.

Hydrangea involucratahybridizes readily with H. asperaD. Don, a complex

taxon found in the eastern Himalaya and the mountains of western China

south to Taiwan, Java and Sumatra. Following McClintock, I have grouped

numerous closely related species as subspecies under this umbrella. I do this

with a certain degree of discomfort because those I have observed in their

wild state appear unquestionably distinct from one another.

Hydrangea aspera subsp. strigosa (Rehder) McClintock will be the firsthydrangea encountered by anyone traveling to many areas of Asia, where it

occurs at lower elevations in mountain valleys. I have seen it in eastern

Nepal at elevations of 1800m, in Vietnam at 1550m and in Sichuan Province

at 950m. It is easily recognized by its very narrow foliage with strigose hairs

on the undersurface and a very late blossoming habit; in fact, I have often

seen it still in blossom in October. Use of the strigose hairs alone as a

diagnostic tool is problematic. In 1998, I established cuttings from a specimencollected on the lower slopes of Mt. Emei clinging precariously to a small

plot of ground between an asphalt highway and a steep cliff to a river below

(collection number: DJHC 98464). This plants globose heads were nearly

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entirely comprised of ray flowers. Michael Haworth-Booth reported that

Ernest Wilson collected a similar type from Emei in the early years of the

20 th century (Wilsons number 4902), but it has apparently been lost to

cultivation. We have introduced this plant to cultivation under the clonalname of Elegant Sound Pavilion (Figure 4) to commemorate the Buddhist

temple near the collection site. The plant was still intact and in good health

when I visited Emei in 2000.

Hydrangea aspera, as most know it in cultivation, is from the higher elevation

taxon known as H. villosaRehd. (or H. asperasubsp. villosa Hort), but which

was reduced to synonomy by McClintock under subsp. aspera. There are few

more beautiful deciduous shrubs than this, with its velvety villose leaves borne

along stems up to 3m (10 feet). In July and August, the plant seems to be

smothered with 25cm (10-inch) lacecaps of lavender-purple fertile florets

surrounded by creamy white ray flowers. By late summer, the woodland

floor beneath the plant is covered with a beguiling purple snow as the petals

dehisce. My collection of this form (number: DJHC 636) from the Wolong

area of Sichuan, at 3000m, has proved to be a sensational plant in our garden

with cymes to 30cm (12 inches) across. In 1998, I collected DJHC 98443

from a similar elevation on Emei Shan and described it as possessing ovate,villose foliage to 20 cm (8 inches) in length and 18cm (7 inches) wide.

Though McClintock chose to reduce H. sargentianato a subspecies of H.

aspera, Rehder gave it species rank. It was introduced from western Hubei

Province by Ernest Wilson in 1908, but I have not visited this area of China

and am unable to confirm if subsequent collections have been made. It

differs from H. asperain what has been well described as a moss-like coating

of hairs on its young stems, as well as large, ovate, substantive leaves ofdeep green covered with a seductive indumentum. The cymes, produced in

mid to late summer are large and flattened. The purple fertile flowers are

surrounded by sterile flowers with somewhat concave sepals of cream. I

have raised this species from seed collected under cultivation and have seen

little variation amongst the progeny, except for a nicely golden variegated

seedling, which we have named Binti Jua (daughter of sunshine). It is a

beautiful addition to the garden but requires proper pruning of the young

plant to produce its fullest potential.

On moderate to high elevations in Taiwan, the Wynn-Joneses and I have

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collected seed from H.kawakamiiHayata (like H. villosa, reduced to synonomy

by McClintock under the subsp. aspera), which impressed us in both foliage

and flowers. One particular specimen at 2395m had felted foliage to 25cm

(10inches) long and 20cm (8 inches) wide while the cymes to 40cm (15 inches)across were held atop sturdy stems to 6m (20 feet) in height. It does not

come as surprise to find that Haworth-Booth described this subspecies as

the most spectacularly fine member of this subsection. However, it has

suffered from untimely cold spells in USDA Zone 8 and overhead protection

should be considered in colder microclimates.

It was not until the autumn of 2000, while north of Boaxing in Sichuan

Province at elevations of 2010m, that I finally encountered a misunderstood

taxon known as H. asperasubsp. robusta(Hook. f. & Thoms.) McClintock (H.

longipes Franch). While hiking through a damp wood in a mostly degraded

agricultural area, I found three specimens of a startling hydrangea with

colossal foliage carried on 30cm (12-inch) petioles. The cordate leaf blade

was 30cm (12 inches) long and 32cm (13 inches) wide. In the autumn of

2002 in eastern Nepal, the Wynn-Joneses, J. Kincaid and I found this same

taxon, though at elevations of 2655m. Bleddyn Wynn-Jones reports this

plant to be common at similar elevations in Sikkim. There is some confusioncaused by Bean (1973), who recognized the name H. longipesbut distinguished

it from the closely related H. robusta, which he admits never to have seen in

leaf.

Subsection 3 Calyptranthe

This subsection, containing some of the deciduous climbing hydrangeas,

appears taxonomically straightforward, although I have found several pitfalls.

The members are well known, if perhaps not well named, by the horticultural

community at large and are amenable to deep shade in USDA Zones 5-10,

where they will climb and use aerial roots to adhere to any compatible

substrate. The subsection is segregated from other hydrangeas by the unique

abscission of the corona (flower petals ) in one bonnet-like structure.

I have observed Hydrangea anomalaD. Don subsp. anomalaand H. anomala

subsp.petiolaris(Siebold & Zuccarini) McClintock (back cover) in numerous

localities, collected seed and grown the resulting seedlings, and I feel quite

satisfied with McClintocks reduction of H. petiolaristo subspecies rank. The

differences that distinguish the two subspecies (fewer stamens, a slightly more

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domed inflorescence and more coarsely toothed leaves in H. anomalasubsp.

anomala) do not seem sufficient to justify separating them as distinct species

especially when one considers the breadth of their geographical range.

H. anomalasubsp.petiolarisis the more northerly of the two and is presumedto be the more hardy. Most climbing hydrangeas grown in North America

and Europe are given this name, whether it has been legitimately applied or

not. This taxon occurs from Sakhalin in N.E Russia through the Japanese

archipelago extending southward to Taiwan. It is commonly encountered

on Ulleong Island (Korea), Cheiju Island (Korea), the central highlands of

Hokkaido, throughout Honshu, Kyushu, Shikoku and Yakushima as well as

the North-Central Alps of Taiwan. In 1993, I found it on Ulleong Island,

off the eastern coast of Korea, co-mingling with its near look-alike and close

relative Schizophragma hydrangeoides, whereas in Taiwan it sprawled over stumps

and up trees amidst the stems of S. integrifolia. On more than one occasion,

I have admired the shine of this vines golden autumn foliage as it emerges

through the fog climbing high into the overstory on virtually every available

tree trunk.

A well grown specimen of this hydrangea in blossom in June is hard to

improve upon, with its shag of lacey white heads held amidst glossy, deep

green foliage. To my knowledge, no selections have been made based on

floral attributes, but I have seen a small non-blossoming specimen in a garden

in the U.K. that is reportedly a cutting from a pink flowered selection from

France. The amount of red pigment in the leaf blade leads me to believe

that eventually this will indeed produce pinkish flowers, and recently it did.

This is not the case in regard to variegated foliage, because after years in

cultivation there has been no departure from the norm in two nearly identicalgolden variegated sports, which occurred spontaneously at virtually the same

time on both coasts of North America. Hydrangea anomalasubsp. petiolaris

Mirranda and Firefly each possess orbicular foliage nearly identically

emargined with yellow. Though their entrance into commerce caused

excitement, we have thus far been disappointed by their lack of vigor in the

garden.

In 1922, Monsieur Henri Cayeux exhibited in Paris a cross he had createdbetween H. anomalasubsp.petiolarisand H. macrophyllavar. roseaHort, which

showed intermediate traits between the two. All plants of Hydrangea

hortentiolariswere reportedly destroyed during the bombardment of Le Havre

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during the end of WWII.

Cheiju-do (Quelpart Island) is a large volcanic outcrop approximately 50

nautical miles from the southern tip of the Korean Peninsula. It boasts a

large inventory of endemic species in addition to sharing a number of specieswith the Japanese Archipelago that lies directly to the south. Geologically,

this location seems a somewhat bizarre mongrel between tropical Fiji and

the Salisbury Plain of England, with tidy rock walls surrounding mossy green

pastures and numerous volcanic cones that rise from the flattened landscape

like druid mounds. Among the endemics that grow here, Hydrangea

quelpartensis, a deciduous climbing species, is frequently found clambering up

the oaks and pines in the dry woodlands of the volcanic slopes. I do not

believe it to have any botanical standing despite the fact that I have collected

seed under this name while on Cheiju-do and purchased plants under this

name while in Europe. The claim that it possesses foliage one quarter the

size of H. anomala subsp. petiolaris can be attributed entirely, it seems, to

juvenility. I find it important to raise this rather esoteric fact because of my

culpability in distributing a deciduous self-clinging vine for several years under

the name of Schizophrama hydrangeoides Brookside Littleleaf . I received it

under this name from J.C. Raulston of North Carolina, who in turn hadreceived it from Brookside Gardens in Maryland. After numerous years of

climbing a tree in the garden, by which time it proved itself quite capable of

producing entirely normal sized leaves, it blossomed, authenticating itself as

H. anomala.

Hydrangea anomalasubsp. anomalaappears virtually identical to H. anomala

subsp.petiolaris, at least superficially and to my eyes. It too is quite commonly

encountered in the mountains of western China and the eastern Himalaya. Ihave collected seed of this species above 2300m in central and eastern Nepal,

at 2860m in Sichuan and at 2700m on the Cangshan in Yunnan. The latter

collection, made in 2000 under the number DJHC 00-0455, came from an

individual that I noted as having very lustrous foliage and cymes to 25cm (10

inches) across. The resultant seedlings have not yet flowered. Finally now

afforded numerous collections of this continental counterpart, with known

provenance, a comparative evaluation of the differences exhibited in

cultivation is underway, though it will be many years before data is

forthcoming.

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Subsection 4 Petalanthe

This subsection of wholly Asian species is characterized by the position

of the ovary (half superior) as well as the fact that the seeds are not winged

or nearly so. Ostensibly, it is an assemblage of vastly under-known but ratherremarkable species. I feel that it is taxonomically complex, riddled with

nomenclatural anomalies and represented in the West mostly by dried

herbarium specimens.

The Kei Peninsula is a large landmass that juts into the Pacific Ocean,

with Osaka on its upper northwest corner and Nagoya to the upper northeast.

We centered our activities from the centrally positioned city of Hashimoto

and explored the large mountain range rising to the southeast.

It was here on our first day that we encountered Hydrangea hirta (Thunb.)

Siebold a species virtually unknown in western cultivation. The rounded

leaves of this species, to 8cm (3 inches), are very distinct in possessing an

extremely dentate leaf margin. It grew in great abundance here in moderate

shade beneath a canopy of deciduous and evergreen trees at approximately

1000m elevation. In May, profuse terminal flowers of light blue are formed

in compact corymbs to 8cm (3inches) across atop 1.25m (4-foot) stems,lacking the expanded sepals on sterile florets that we have come to associate

with the hydrangeas as a whole. Though I already possess plants of this

species, raised from seed provided by the Tsukuba Botanic Garden in Japan,

this was my first encounter with it in the wild and I found it a handsome

shrub that certainly deserves more evaluation for use in Northwest gardens.

It is not held is very high esteem in most literature.

In this area, we found what I have come finally to regard as Hydrangeascandens Ser., another rare species that certainly deserves more recognition

than it currently enjoys in the West. It has a wide range throughout east Asia

and the nomenclature compressed into this variability is in a constant state

of fusion and fission. We had already collected seed of this species on Shikoku

Island, where we found it common as an understory shrub in a wide range

of elevations. The foliage is quite narrow, to less than one inch, with serrations

present on the leaf margin along the terminal quarter of its total length of

10cm (4 inches). In full sun situations, the foliage had transformed to lovelytints of burgundy in good complement to its characteristic brownish purple

stems. This species has already flowered in my woodland at Heronswood,

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where I raised it from seed nearly 15 years ago. It performs quite admirably

in the climate of the Puget Sound area where it often flowers before June

producing quantities of fragrant, 10cm (4-inch) corymbs surrounded by

creamy white, fading to yellow, sepals of the sterile florets. I cultivate botha variegated as well a double-sepaled forms of this taxon originating from

Japan.

Hydrangea scandens is known from numerous variants in herbaria and

reported in the literature, most of which have originated on the mainland of

China. One of those, referred by McClintock to H. scandenssubsp. chinensis

(Maxim.), is H. angustipetala Hayata (H. yayeyamensis Koidzumi). It is this

plant that I have observed in blossom in very early spring both on extreme

southern Kyushu as well as Yakushima further to the south. It is easily

recognized, with lance-like, extremely dentate leaves to 10cm (4 inches) in

length, appearing more like the foliage of a forsythia than hydrangea. The

airy inflorescence is of a respectable size with loose corymbs, to 12cm (5

inches) across, of white flowers surrounded by white, fading to pink, ray

flowers.

While in Sichuan Province in the autumn of 2000, on the border with

Yunnan, I observed a hydrangea in full blossom in mid-October at lower

elevations, possessing narrow, coriaceous foliage and large flattened cymes

of white flowers surrounded by white florets. These were collected under

the numbers 00-0492 and 00-0499 and assigned temporarily to H. scandens

subsp. chinensis(Figure 5). In the autumn of 1999, while on Fan Si Pan, the

tallest mountain in Viet Nam at elevations of over 3000m, we collected seed

from an evergreen species, common on the lower slopes. The lance shaped

leaves to 12cm (5 inches) were glabrous above and a striking purple beneath,while the cymes of white fertile flowers and lavender sepals were quite

handsome. This was collected under HWJ 99736 and assigned the provisional

name of H. scandenssubsp. indochinensis(H. indochinensisMerrill). Superficially,

it resembles H. lobbii (Maxim.) - another entity attributed by McClintock to

H. scandenssubsp. chinensis- which we observed at lower elevations in Taiwan

a month later. I have grown this evergreen shrub in our USDA Zone 8

woodland and it thus far seems to be quite content.

Subsection 5 Heteromallae

Whereas Subsection 4 Petalanthe contains mostly unknown hydrangea

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species, Heteromallae, characterized by terminally winged seeds and globose

seed capsules, includes one of the best known and cherished of all flowering

shrubs. Hydrangea paniculataSieb., known to the lay audience as the peegee

hydrangea, is one of the hardiest and most handsome of hydrangeas grownin North America and Europe. It has a large geographical range, from

Sakhalin and NE China to Taiwan through the entire Japanese Archipelago.

The flowers, as one would expect, are carried in panicles with sterile florets

spread throughout the inflorescence. These are born terminally on each

branch and are produced on current years wood.

In the autumn of 2001, while on the chilly mountain slopes of Mt. Daisen

in Japan, I collected seed from specimens rising to nearly 7.5m (25 feet) in

height. In 1999, those plants we observed in Taiwan, were more demure

with an intriguing bluish green colored foliage. Sargents collection from

Hokkaido in 1893 led to development of Praecox, which blossoms nearly

six weeks earlier than the much celebrated H. paniculata Grandiflora, the

above mentioned peegee, emitting a fragrance that has been aptly described

as a heady infusion of horse and Chanel No5. The peegee was imported

from Japan in the latter years of the 19thcentury and, with its startling heads

of nearly all sterile florets and tough demeanor, was almost the solerepresentative of the species in cultivation for practically 100 years. Selected

forms such as Floribunda, Interhydia (Pink Diamond), Greenspire,

Brussels Lace, and Unique have grabbed market share since. I have not

grown the highly touted H. paniculataTardiva which is reported to blossom

much later than the others, often not commencing until mid-September.

Hydrangea heteromalla D. Don has become the overall name for a rather

large assemblage of variable ecotypes occurring from the eastern Himalayathrough the interior to eastern China. It grows to immense proportions in

central and eastern Nepal where I collected it in 1995 and 2002 under

numerous numbers at elevations of 2000 to 3500m. The foliage of the

Himalayan forms are ovate linear to nearly 30cm (12 inches) in length and

glabrous above with adpressed hairs beneath. The inflorescence is a terminal

cyme of white fertile flowers and white or pink ray florets. Interestingly, I

have not observed any red pigment in the petioles of the Nepalese plants.

From my observations, this trait enters the picture in the Sikkim populations

and intensifies as one travels further east into western China, where I have

collected numerous forms possessing dark green, nearly orbicular foliage

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and striking, lipstick-red leaf stems. Hydrangea heteromalla Bretschneiderii

(H. bretschneideri Dipp) represents collections made in the mountains near

Beijing and possesses a framework with handsome exfoliating cinnamon-

colored bark, while H. heteromallaSnowcap, grown under the name H. robustafor many years in England, is touted for its large cordate foliage and

substantive flattened white cymes. The latter is rare in commerce in North

America.

Subsection 6 Macrophyllae

The confusion surrounding the naming of H. macrophyllaand H. serratais

due mostly to the rules designed by the International Code of Botanical

Nomenclature to prevent such confusion. Through the untangling of a legionof sticky webs, a rather interesting story unfolds while possessing all of the

parameters necessary for a perfect storm.

As already noted, those hydrangeas first described from Japan, through

Thunberg, were named Viburnum macrophyllumand Viburnum serratum. The

former, a selection later named Otaksa possessed an inflorescence comprised

virtually of all sterile florets, and is thought to have been imported into

Japan from China where it was already a popular garden plant in the courtsof Imperial China. The latter probably came to Thunbergs attention by way

of fodder brought for animals on Deshima Island, an artificial Archipelago

in Nagasaki harbor where all visitors to Japan during the 18 thcentury were

forced to live.1

1It was on Deshima that Philipp Franz von Siebold fell in love with Otaksa-san, his

Japanese lover whom he was forbade by the Japanese government from marrying.Von Siebold took Otaksa and the daughter they had produced with him when heleft Japan in 1829, however, a shipwreck led to the finding of a forbidden map ofJapan that von Siebold had acquired. He was arrested and later banished; Otaksaand their daughter were not allowed to leave with him.

2There remains a great deal of speculation as to exactly whom the name Hortensiacommemorates. Commersons mistress, Jeanne Baret, who accompanied him dressedas a man on Bougainvilles round-world voyage, is ruled out. Queen Hortense was

born several years after Commersons death. Mme Lepaute, the wife of a clockmakerand herself a respected mathematician is often cited, however, her Christian namewas Nicole-Reine. Most likely is the daughter of the Prince of Nassau-Siegen whosefather had accompanied Commerson with Bougainville.

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About the same time, the French botanist Lamarck published the name of

Hortensia opuloides, the name given to a plant that the naturalist Commerson

had sent to Paris from the island of Mauritius, where it grew in the garden

of explorer Pierre Poivre.2

This invalid genus name is still used to somedegree in French commerce to represent those cultivars possessing mostly

infertile florets.

In 1788, Sir Joseph Banks presented to Kew a sterile-floreted form he had

procured from China. This was properly placed in the genus Hydrangeaand

described in 1792 as H. hortensis. This clone is still common along the mild

southern coasts of England where it is now grown as H. macrophylla Sir

Joseph Banks

Though it is now apparent that by trying to sort out and rename these two

hydrangeas as we know them, adhering to the rules of priority, would only

cause more damage than good, it is understandable and meritorious that

many have tried. Ernest Wilson, Michael Haworth-Booth and Elizabeth

McClintock all weighed in heavily to make things right. Though there is still

plenty to be learned, what we currently have is a better understanding of two

species.

Hydrangea macrophylla, with its typical large, glossy, somewhat fleshy leaves,

is common throughout coastal Japan at relatively low elevations, frequently

found hugging windswept beaches. I have observed large populations of

this growing on the Chiba Peninsula, south of Tokyo, in 1995 as well at

1997. Of course, the normal form in the wild possesses both fertile and ray

florets. Hydrangea macrophylla Seafoam, a sport from Sir Joseph Banks,

with rather large cymes of blue fer tile flowers and white sterile florets, is

probably the closest thing to true H. macrophyllain cultivation. There havebeen subsequent introductions of this from the wild, including Wilsons 1917

collection from Oshima, however, they have made little if any impact in

Western horticulture. Hydrangea macrophyllablossoms on second year wood,

making it thusly inappropriate for use in any climate where winter damage

will occur. For those blessed with warmer gardening climates, there exists a

voluminous listing of cultivars of H. macrophyllato choose from.

Thunbergs Viburnum serratum did indeed represent a different specieshailing from the higher elevations of Japan and Korea. Hydrangea serrata

(Thunb.) Ser. (H. macrophyllasubsp. serrata(Thunb.) Mak.) is thusly a much

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hardier species and possesses the ability to blossom on new wood. I have

encountered and collected seed of this on numerous adventures on Hokkaido,

central and northern Honshu, Cheiju Island and most notably while on Mt.

Chiri on the southern tip of the Korean Peninsula, in 1993 and 1997, at1500m. Here the hillsides are smothered in this species, at a much greater

degree than I have ever witnessed while in Japan, and must provide a dazzling

sight when in blossom. I have come to expect the typical wild form of this,

from both Japan and Korea, to offer blue fertile flowers in a slightly dome-

shaped corymb, encircled with ray-florets of blue, if provided acidic soils, or

suffused with pink when grown under more basic conditions.

A collection from our time on Chiri-san in 1997, under the number of HC

970416, was a self-layered lower branch from a specimen possessing sterile

florets with double-sepals. Heronswood entered this into the trade under

the cultivar name of Chiri-san Sue, in honor of Sue Wynn-Jones, who

accompanied us on that trip and who had waited a much too inappropriate

length of time for us to return to our pre-ordained meeting spot on that

chilly, rainy day.

It was, however, in Japan that I first observed a vast array of hydrangea

cultivars based upon H. serrata. Unlike the European hybridization of

hydrangeas, which focussed primarily on increasing the flower size of H.

macrophylla, the Japanese breeding programs instead selected for delicate

subtlety, which translates to pure charm in the garden. Unfortunately,

hydrangeas from Japan are forbidden from entry in the United States, though

Europe does not ban their importation. Furthermore, as Hydrangeas can

come into the U.S. through Europe under post entry quarantine, these exciting

new plants will ultimately be made available through the trade, though notnecessarily at the pace I would prefer.

Consider H. serrataIzu No Hana (front cover), one of dozens of classical

cultivars from the Japanese tradition, each with names that are nearly as

enticing as the floral effects themselves. With this cultivar, the flattened disk

of indigo blue flowers are surrounded by sterile florets of similar hue, much

in the same fashion of other lacecap hydrangeas. In this cultivar, however,

each sterile floret possesses a double dose of sepals, creating miniature blueroses that arc from the flower heads on wiry stems, suggesting that of

intricate fireworks at precisely the moment of ignition.

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This charming flower type is seen in numerous named Japanese cultivars,

including the beguiling pink H. serrataJogasaki, as well as the large headed,

pure white Miyake-Tokiwa. A single stem of the latter, with miniature white

tassels opening from chartreuse buds, could by itself be carried as a tastefullyexquisite bridal bouquet.

Flower heads possessing sepals richly edged in contrasting hues comprise

another substantial subset of the Japanese mountain hydrangea. The

blossoms of H. serrataBeni Gaku open with sepals colored brilliant white

bordered in rich cerise. As the floral effect matures, the definition between

these two colors dim, while melding to enchanting shades of rose pink.

In foliage as well as flower, H. serrataoffers numerous irresistible selections.The leaves of H. serrata Kiyosumi (Figure 6) emerge in tones of rich

burgundy, retaining these colors throughout spring and early summer. In

near perfect combination, its flowers open from deep crimson buds, later

broadening to heads of startling white picoteed with rose. Hydrangea ser rata

Beni Nishiki brandishes intensely colored blossoms of cherry red held amidst

a flurry of sprightly cream-splashed leaves.

Section II Cornidia

The Section Cornidia is comprised entirely of evergreen species, most of

which are scandent shrubs or lianas and naturally occur from the Neo-Tropics

south to southern Chile. The Section is delineated by the presence of cup-

shaped floral bracts that enclose the inflorescence and dehisce upon opening,

superficially not entirely unlike those found in H. involucrata. The inflorescence

is comprised entirely of fertile florets; i.e., the sterile ray flowers are absent.

These are chiefly unknown in cultivation though at least three species haverecently become better known to a realm of USDA Zone 8-12 gardeners

beyond the cognescenti.

Subsection 1 Monosegia

A simple corymb sets this group aside from the only other subsection in

Section Cornidia. I have little experience with or knowledge of three of the

seven species currently enveloped by Monosegia, many of which, to my

knowledge, remain unmolested by the gardeners hand in their native habitats.

Not so, thankfully, with Hydrangea integrifolia Hayata (Figure 7), which I

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consider one of the finest evergreen vines that I grow. I happened upon a

scrambling terrestrial specimen of this species in the Edmonds, Washington

garden of Marlee Hedges in the late 1980s and the oldest specimen in my

garden originates from the cuttings she offered me at that time. Much later,in 1999, I collected seed of this species growing in its native range of Taiwan

at elevations of 2395m where it was climbing specimens of Trochodendron

aralioides to 12 m (40 feet) in height. It is the only member of the section

Cornidia to occur in the Old World and naturally occurs in both Taiwan and

the Phillipines.

It is a very handsome species with deep green linear obovate foliage, very

leathery in texture, to 20cm (8 inches) in length, adhering to the stems in

pairs by way of deeply hued red petioles. The leaf margin is slightly crenulate.

As with H. anomala, the stems adher to its host substrate by way of

adventitious roots. In late June, terminal cymes of white flowers open from

buds that are at once both curious in appearance while conjuring forth an

overinflated anticipation. As the attending bracts fall and the flowers expand,

for a short period it appears as if large popcorn balls have been stashed

among the greenery, though fully expanded, the effect is much as with the

better known deciduous species without the outer row of sterile florets.

My original garden plant of H. integrifoliahas achieved over 9m (30 feet) in

height upon the lower trunk of a Douglas fir, though has thus far remained

quite stingy in blossom. An additional plant representing seed collections

from Taiwan has proven to be much more generous in this regard despite its

relative youth.

Hydrangea seemaniiRiley (Figure 9) has been anything but reticent to blossom

in our woodland, now smothered with flattened cymes of creamy whiteflowers without ray florets. It is very closely allied to H. integrifoliadespite

the enormous range differential. Hydrangea seemaniiis found naturally occuring

in the mountains of SW Mexico in the Sierra Madre Occidental at approximate

elevations of 2000 to 2600m; in fact it is the only member of the genus to

occur within the political boundaries of this country. The leaves on the

clone that we grow are broadly ovate to 15cm (6 inches) in length and 60cm

(2 feet) wide and extremely glossy on the upper surface. It is vigorous ingrowth and has climbed over 10.5m (35 feet) in our woodland in less than 10

years.

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Hydrangea asterolasia Diels is the only other American species in this

Subsection to possess flowers of white rather than pink. It is found naturally

occurring from Costa Rica south to the Andes of Ecuador and Columbia.

The ovate foliage of the clone that we currently cultivate, from wild collectedEcuadoran stock, is ovate and coriaceous to 10cm (4 inches) in length,

decidedly smaller than H. seemaniiand H. integrifolia, while both the new stems

and leaf petioles are coated in a characteristic brownish tomentum. Though

I have traveled in the mountains of Costa Rica where this is reported to

occur, my only experience horticulturally is with the young specimen we have

integrated into our woodland garden.

While in Costa Rica, however, I delighted in encountering my first pink-

flowered, evergreen climbing Hydrangeaspecies (Figure 8), both in the high

treetops of Monteverde as well as in high elevations of the Cordillera De

Talamanca south of San Jose. Though I presumed these to be Hydrangea

peruviana Moric., subsequent reading suggested one of two very closely related

species that occur in the same geographical range. Hydrangea oerstediiBriq.and

H. peruvianaboth possess very showy cymes of pink fertile flowers surrounded

by large sterile florets. The difference between the two is based entirely

upon the length of the stamen and one that may not stand the test of time asmore material becomes available for study. As those I observed were in full

flower, in February, I was unable to gather seed while my attempt at cuttings

also failed.

McClintocks monograph retains three additional species in this subsection;

H. preslii Broiq, H. diplostemona Standley and H. steyermarkii Standley. All

three reportedly possess pink flowers and naturally occur from Guatemala

south to the Andes of Ecuador, Columbia and Peru.

Subsection 2 Polysegia

It is the compound cyme (i.e., one above another), that distinguishes this

subsection from Subsection Monosegia, and, of the four currently adherred

here, my interaction with its constituency is restricted to only one; Hydrangea

serratifolia Engl.

Hydrangea serratifolia has purchased a rather schizophrenic episode intaxonomy, though as always the case, this malady originates not from the

plant itself but from the progenitor of its name. The young Hooker, having

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come upon this liana in Chile in 1833, put this to a new genus, Cornidia, while

tagging on an apt specific epithet, integerrima, which translates to smooth or

entire margined. Indeed, the leathery, ovate semi-gloss green leaves of this

species, to 10cm (4 inches) in length, do not possess the degree of jag foundon others in this section. Never mind the fact that the name H. integerrima

might be confused with H. integrifolia; this is a conflict that mature gardeners

can cope with.

Exactly why, however, this species consummated its classification with

exactly the opposite and erroneous reference will never be fully actualized.

Nonetheless, this smooth-margin-leafed hydrangeaconjures forth an image

of teethly dentation that does not actually exist.

In the southern Andes in 1998, my friends Kevin Carraibine, Jennifer

Macuiba and I encountered this species growing upwards to 18m (60 feet)

along the main trunk of a Nothofagus, while later observing it to 30m (100

feet) in mammoth specimens of Eucryphia cordifolia. We were able to collect

its seed from the large heads of flowers only in instances when its host tree

had retired to a decidedly less intimidating horizontal stance on the floor of

the Alercean rainforest.

The species has flourished in our woodland at Heronswood, ascending to

12m (40 feet) in less than a decade along the main trunk of a second growth

Douglas fir, though it has yet to grace the garden with blossom. I have no

doubt that it will do this in time.

This subsection currently supports the existence of three additional species,

and although I have not observed the herbarium specimens that meagerly

represent their being in modern science, based on the collection notes and

physical condition of the holotypes and McClintocks reservations of their

preservation, I would not put good money on their timeless qualities.

Hydrangea tarapotensis Briq. is noted from the Andes of Colombia, Bolivia

and Peru from 800 to 1500m. Hydrangea felskiiSzyszyl. is found in the Andes

of southern Ecuador and northern Peru, 2100m while H. mathewsiiBriq. was

first collected in the Andes of northern Peru.

This paper does not deal with the closely allied, and ornamentally fer tile

genera of Schizophragma, Pileostegia, Decumariaand Dichroa, all found within

the realm of Hydrangeaceae and with variable representation in Western

horticulture.

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References and Further Reading

Bean, W.J. 1973. Trees and Shrubs Hardy in the British Isles. Volumne II D-M.Fully revised eighth edition. In collaboration with The Royal Horticultural

Society. Butler and Tanner Ltd., Frome and London.Bondurant, C.S. 1887. Botanical Medicine Monographs and Sundry. American

Journal of Pharmacy. 59(3).

Department of Plant Resources, Ministry of Forests and Soil Conservation. 1997.The Flora of Phulchoki and Godawari. Thapathali, Kathmandu.

Dirr, Michael A. 1983. Manual of Woody Landscape Plants; Their Identification,Ornamental Characteristics, Culture, Propagation and Uses. StipesPublishing Company. Champaign, Illinois.

Gentry, Alwyn H. 1993. A Field Guide to the Families and Genera of WoodyPlants of Northwest South America. University of Chicago Press. Chicagoand London.

Hara, Chater and Williams. 1982. An Enumeration of the Flowering Plants ofNepal Volume 3. Trustees of British Museum of Natural History. London,UK.

Haworth-Booth, Michael. 1984. The Hydrangea. 5th revised edition. Constableand Company Ltd. London, UK.

Hillier Nurseries. 1992. The Hillier Manual of Trees and Shrubs. Redwood PressLtd, Melksham, Wiltshire, UK.

L. H Bailey Hortorium, Cornell University. 1976. Hortus Third. MacmillanPublishing Co., Inc. New York, N.Y.

Lancaster, Roy. 1989. Travels in China. Antique Collectors Club Ltd.Woodbridge,Suffolk, UK.

Lancaster, Roy. 1995. A Plantsmen in Nepal. Antique Collectors Club Ltd.

Woodbridge, Suffolk, UK.

Lawson-Hall, Toni and Brian Rothera. 1995. Hydrangeas, A Gardeners Guide.B.T. Batsford Ltd. London, UK.

Li, H. L. 1963. The Woody Flora of Taiwan, The Morris Arboretum and Divisionof Biology of the University of Pennsylvania. Livingston PublishingCompany. Narberth, Penn.

McClintock, Elizabeth. 1957. A Monograph of the Genus Hydrangea.Proceedings of the California Academy of Sciences, Fourth Series.29(5):147-256.

Mallet, Corrine. 1994. Hydrangeas - Species & Cultivars Volume 2. Centre dArtFloral. Varengeville s/mer, France.

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Mallet, Corinne, Robert Mallet and Harry van Trier. 1992. Hydrangeas - Species& Cultivars. Centre dArt Floral. Varengeville s/mer, France.

Ohwi, Jisaburo. 1984. The Flora of Japan. Edited by Frederick G. Meyer andEgbert H. Walker. Smithsonian Institution. Washington, DC.

Polunin and Stainton. 1984. The Flowers of the Himalaya. Oxford UniversityPress. Oxford, UK.

Radford, Ahles and Bell. 1968. Manual of the Vascular Flora of the Carolinas.The University of North Carolina Press

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Figure 1. Hydrangea arborescens subsp. radiata.

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Figure 2. Hydrangea sikokiana.

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Figure 3. Hydrangea involucrata.

Figure 4. Hydrangea aspera subsp. strigosaElegant Sound Pavilion.

Photo:Dan

Hinkley

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Figure 5. Hydrangea scandens subsp. chinensis.

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Figure 6. Hydrangea serrata Kiyosumi.

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Photo:DanielMos

quin

Figure 7. Hydrangea integrifolia.

Figure 8. Hydrangea sp. (with an affinity to H. peruviana).

Photo:Dan

Hinkley

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Figure 9. Hydrangea seemannii.