Cultivation of geissorhizasThe complaint is often heard that the most desirableGeissorhiza species like G. radians and G. eurystigmaare difficult to bring into flower, and even more difficultto maintain in cultivation over an extended period.Firstly, it must be remembered that with one or twoexceptions, all the species require a definite summerdormant period during which the corms have to be keptcompletely dry. This makes them unsuitable for generalgarden cultivation in summer rainfall areas (they arealso frost tender), as well as in winter rainfall areaswhere most gardens are irrigated during summer. Thedepredations of guineafowl, mole rats and porcupinesmake it quite impossible to cultivate geissorhizassuccessfully in open garden situations over an extendedperiod, with the single exception of the ubiquitous andprolific G. aspera. The only successful way to cultivatethem is in containers or in raised beds that are mole-proof and can be protected from other wildlife.Secondly, it is important to note that many geissorhizasoccur in waterlogged soil in their natural habitat (likeG. radians and G. mathewsii), so under cultivation, thesoil medium should never be allowed to dry out duringthe growing period. A single short period of excessivesoil desiccation can result in the flower-buds aborting,followed by rapid yellowing of the leaves andpremature dormancy. A position receiving full sun orvery good light for at least half the day is required byall species listed here. Deep plastic pots with a diameterof 20-25 cm are recommended, and I suggest a growingmedium of equal parts finely sifted, well-decomposedcompost, and fine river-sand. Terracotta pots areunsuitable as they dry out far too rapidly. Plant cormsin late autumn (April- May) in a thin layer of pureriver-sand, fill up the rest of the pot with the recom-mended growing medium up to 10 mm above-,the top ofthe corm, and water well. After the leaves haveappeared, water twice a week, and increase wateriNg asthe flower-buds begin to appear as well as throughout

. the flowering season in spring.Pots of species like G. radians and G. mathewsii like_

being placed in saucers kept filled with water over 1:heflowering period. The flowers of geissorhiza~ only openfully on hot, still days, and this is a good time to hand-pollinate them in order to ensure a successful seedharvest. Gather ripe pollen from a few flowers by lightlypinching the anthers with the thumb and index fingeruntil it adheres, then transfer the pollen by very lightlypinching the delicate, branched stigmas of flowers otherthan those from which the pollen was taken. Seedsmature within four to six weeks and watering should begradually reduced once the leaves begin to turn yellow,when the containers should be allowed to dry outcompletely and can then be moved to a cool drylocation for the summer.

Geissorhiza aspera (blou sysie) is a very commonspecies found growing in large colonies in many partsof the south-western Cape, where it flowers from latewinter to spring. It is probably the easiest one to grow,and the only species that could be considered forgarden cultivation in mild climates with dry summers(such as in moist pockets in a rock garden) as it seedsitself prolifically. Its flowers are small and come inmany shades of blue - and occasionally - pure white.

Opposite page. Geissorhiza mathewsii.Above. Geissorhiza darlingensis.Below. Geissorhiza monanthos.

Geissorhiza darlingensis(geel kelkiewyn) is an exceptionallyrare species from the Cape westcoast which is very easily culti-vated. It has very large, lemonyellow flowers and a deep purplish-black throat, and flowers relativelylate in the season - from early to lateOctober. The base of the leaves andpeduncle are sticky and always havesand grains attached to them. Thisspecies usually sets copious seedwithout the need to hand-pollinate,and has been available from theKirstenbosch seed catalogue formany years.

Geissorhiza eurystigma(wine cup, kelkiewyn) is one of themost attractive geissorhizas with Above. Geissorhiza radians. Below.Geissorhiza splendidissima.large, dark blue flowers with redcentres (see cover photograph). It looks very similar toG. radians, but differs mainly in its distinctive featherystigma and lacks the thin, bright white band dividingthe petals, as well as the single dark purple markingnear the base of each petal. Hand-pollination of flowersis essential in order to ensure a good seed crop. It isvery easily cultivated and flowers from mid to lateSeptember.

Geissorhiza imbricata (geel sysie) is a very variable,relatively tall species with a wide distribution inseasonally inundated areas of the south-western Cape.It is a very easily cultivated, free-flowering plant withsmall white or pale yellow flowers often flushed withred on the undersides of the outer petals. It usually setsseed without the need to hand-pollinate, and flowers inSeptember and October. ~

Geissorhiza inflexa (syblom, witsyblom) is a common '':,r

species that occurs in many colour forms, ranging froinwhite and many shades of pink to deep pinkish-red, andis one of the most reliable flowerers. It has distinctivehairy leaves, and under ideal conditions, it can be;'induced to flower in as little as seven months fromsowing the seed. It can tolerate less moist conditionsthan most other geissorhizas, and is one of the earliestspecies to bloom - from early August to mid-September.

Geissorhiza mathewsii (wine cup, kelkiewyn) is acritically endangered species, known from just a fewsites on the Cape west coast. Newly introduced intocultivation from Kirstenbosch, this plant is one of theeasiest to grow, provided the growing medium is keptconstantly moist throughout the growing and floweringperiod. Its, flowers resemble those of G. radians, but aresmaller and less cup-shaped, and it has distinctive flat,ribbed leaves. This highly recommended plant flowersfrom late August until the end of September.

Geissorhiza monanthos (bleek sysie). The large, deepviolet or purplish-blue flowers of this plant from theCape west coast make it one of the most desirable in thegenus. Seedlings can flower in as little as seven monthsfrom seed, but mature corms appear to be rather short-lived~ and it is advisable to re-propagate this plantregularly from seed, or remove and 'grow-on' the manycormlets produced at the base of the mature corm.It flowers from September to the end of October.

Geissorhiza radians (wine cup, kelkiewyn, witringkelkiewyn). This west coast endemic is one of the mostdesirable and well-known of all geissorhizas. However,successful cultivation requires a constantly moistgrowing medium during the winter growing period, aswell as during the spring flowering period. It prefersbeing grown in raised beds out in the open, but can alsobe successfully grown in plastic containers placed infull sun and immersed in water during the floweringperiod. Hand-pollination of flowers is essential in orderto ensure a good seed crop, and it flowers in Septemberand October.

Geissorhiza splendidissima (blue pride-of-Nieuwoudtville) is one of the most beautiful blue-flowered plants in the bulb world! Endemic to the

Bokkeveld Plateau aroundNieuwoudtville, this early-flowering, large-flowered specieswith shiny petals is easily culti-vated, and can tolerate drier condi-tions than species like G. radiansand G.mathewsii. It is essential tohand-pollinate the flowers in orderto ensure a good seed crop. Seedshave been available from theKirstenbosch seed catalogue formany years. Its flowering period isearly August to mid-September.

Geissorhiza tulbaghensis is oneof the most easily cultivatedgeissorhizas, yet in its restrictedwild distribution in the south-western Cape, it is becomingincreasingly rare because ofcontinued agricultural expansion.This highly recommended, veryfloriferous plant has one of thelargest flowers in the genus, and isa particularly good subject forcontainers. It is essential to hand-pollinate the flowers in order toensure a good seed crop. Regularlyavailable from the Kirstenboschseed catalogue, this species flowersfrom mid-August until the end ofSeptember.®

Geissorhizas are propagated mainly by seed, andby the removal of cormlets from the base of themature corm. Seed size varies considerablyamong the species, from the tiny rounded seedsof G.mathewsii, to the comparatively large onesof G. splendidissima. Seeds are best sown in lateautumn (late April or May in the SouthernHemisphere) after cooler weather has definitelyset in. Deep plastic seed trays or deep seedbedsare recommended, and a situation receivingmorning sun or at least very good light isrequired. Protection from heavy winter rains isrecommended, such as is experienced in thesouthern suburbs of the Cape Peninsula. Thesowing medium should be well drained yet itshould not dry out too quickly, and a recom-mended sowing medium is equal parts of fineriver-sand and finely sifted compost. It is veryimportant to sow seeds thinly and evenly, inorder to reduce the risk of attack by damping-offfungi, to which the seedlings are very suscep-tible. Species with very small seeds likeG.mathewsii and G. radians can be covered witha layer of about 2 mm, while those with largerseeds like G. tulbaghensis and G. splendidissimacan be covered by up to 4 mm.

Fresh seeds usually germinate within fourweeks, and it is important to keep the mediumconstantly moist by regular watering every two tothree days with a fine rose. It is best to water inthe morning so that excess moisture canevaporate from the minute hair-like leaves during

the rest of the day, to lessen attack by damping-off fungi. Under idealC'elnditions,some species like G. radians and G.mathewsii can bebrough't.into flower in as little as seven months from seed, butgenera:lly,first flowers can be expected towards the end of the secondyear of growth.

During the summer dormant period, dry soil containing maturecorms can be placed over a fine sieve, in order to remove daughterjorms,'which are easily detached from the base of mature corms.These can be replanted immediately in dry growing medium, or bestored in paper packets until the following autumn. Be sure to dustthe corms with Bexadust when storing them loose in packets, as theyoften fall prey to attack by mealy bug when stored loose.

Pest and disease controlGeissorhizas are not particularly susceptible to pest attack, but aphidsdo frequently feed on developing flower-buds, which can becontrolled with Bio Kill garden spray. Geissorhiza corms are suscep-tible to infestation by mealy bug, which is best treated by drenchingplants in active growth with chlorpyrifos. Adult corms are subject tofungal rot when not allowed a completely dry dormant summerperiod. Seedlings very often fall prey to the Pythium damping-offfungus, which can be overcome by sowing the seeds thinly in awell-aerated environment, and by dusting the seeds with Kaptanimmediately prior to sowing.

SOURCES OF SUPPLYSeeds of Geissorhiza species are regularly available from the annual Kirstenboschseed catalogue, available free to members of the Botanical Society of SouthAfrica. Corms can sometimes be purchased at the Society's annual Garden Fair,and specialist seed and bulb nurseries such as those which advertise inVeld if Flora, also stock several species.