SHAPED BY SUFFERINGThe Eastern Cape has produced some of the most enduring and

successful garden plants in the world.

by Ernst van Jaarsveld, Kirstenbosch

Gardens originated in theNorthern Hemisphere whenhumans started cultivating

plants that provided nourishment,medicines, clothing and buildingmaterial. Gradually gardening foraesthetic appeal emerged and todaygardening is the most popular hobbyworldwide. There are no fixed rules,people grow what they like andenjoy, and gardeners are alwaysready for a new challenge. But ingeneral it is the plants fromabusive backgrounds that havebecome the most enduring andpopular garden plants.

Disturbing practicesGardening is very disturbing toplants. Disturbances include thecultivation of soil, planting, trans­planting, pruning and trimming,adding compost and fertilizers,creating ponds, paths and otherstructures, breaking these down,and cutting and disturbing roots.Invasive plants from neighbouringterritories have to be regularlyweeded out, necessitating aregular disturbance of the soil.The very act of cultivating the soilbenefits the emergence of pioneerplants - usually known to us asweeds. (New gardening techniques

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using mulches have helpedsomewhat.) Other disturbancescome from the activities of dogs andcats, and domestic animals as wellas trampling from humans,especially from children.

To survive in a garden, plantshave to be 'garden-fit'. Many plants(for exampl.e, fynbos species likeericas, proteas and buchus) have a

Above. The marsh rose Orothamnus zeyheri,admired by all but not suitable for the garden.Top. The thicket vegetation of the Eastern Cape,cradle of the world's most popular 'garden-fit'plants. Photos: E. Van laarsveld.

very sensitive root system whichdoes not like any disturbance, asthey originate in areas where theydid not have to adapt to tramplingor grazing disturbances. Some plantshowever, grow easily in any garden,and are able to tolerate humanhandling, neglect and ill treatmentbetter than others. 'Garden-fit'plants that spring to mind are

spekboom (Portulacaria afra) ,Pelargonium, hen-and-chickens(Chlorophytum comosum),kerkei (Crassula portulacea),kransaalwyn (Aloe arborescensJ,and Plumbago. The secret oftheir success is their ability totolerate disturbances, whichnaturally would be grazing ortrampling animals, droughts,frost or poor soil. This abilityequips them to withstand therigours of growing in a garden.So if you blame yourself for thedeath of your erica, relax, it diedfor other reasons.

Garden-fit plants from theEastern CapeIn my series of articles* on 'veldgardening' (now consolidatedinto a book, Wonderful waterwisegardening), I emphasized how togarden effectively with

Veld & Flora March 2001

The world's most popular garden plant, the pelargonium, graces the streets of Europe.It originated in the Eastern Cape. Photo: E. Van Jaarsveld.

indigenous plants adapted to aspecific ecological region in SouthAfrica. Obviously, a plant wouldprefer to grow in its own region, butthere are some indigenous plantsthat thrive in gardens throughoutthe world. If a plant thrives ingardens within its ecological regionI call it 'locally garden-fit', and if itthrives in each area, I give it a good'overall garden-fitness' score. Mostplants with a high 'overall garden­fitness' score originate in theEastern Cape, which can beconferred with the title of 'Cradle ofthe world's most adaptable gardenplants'. Plants from this region havehad a major horticultural impact onthe world. On the annual Dutchgarden and floral market at Alsmeer,plants are rated according to theirsales (reflecting their popularity)and many South African plants arehigh up on the scale. Pelargoniumcultivars have been rated for manyyears as the tops, and colourfulpelargoniums grace the balconies ofbuildings and gardens in citiesthroughout northern hemisphere.Other popular houseplants fromSouth African include the spiderplant or hen-and-chickensChlorophytum comosum, forest lilyClivia miniata and many of ourherbaceous, succulent and bulbousplants.

Plants from the Eastern Cape areeasy to grow, adaptable, hybridizeeasily and can take rough handling.They are remarkably tolerant ofdisturbance, having evolved side byside with grazing animals. In theirhabitat, grazing and trampling is amajor driving force (just as fire isthe driving force for adaptations infynbos, grassland and bushveld). Inthe fertile soils of the Eastern Cape,many plant species are highlynutritious and in great demand forgrazing. This thicket vegetation usedto carry dense populations of largerand smaller mammals (includingdomesticated animals). Evolutionaryresponses to grazing pressureresulted in thorns, bitter sap (achemical defence) or camouflage!

Some plants even exploit thisabuse. Many rely on disturbance inorder to vegetatively reproduce.The spekboom (Portulacaria afra)sacrifices its branches to grazingmammals, but when the branchesare dropped they re-root quickly,forming new plants. Gasteria andAdromischus leaves are brittle andreadily detach when grazed ortouched, but the leaves or fragmentsthat fall rapidly re-sprout, often inthe protective arms of thorny plants

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such as Carissa haematocarpawhere only smaller grazers (theleopard tortoise, dassies, bushpigsor porcupines) can reach them.Pregnant onions (Ornithogalumlongibracteatum) and the cliff firelily (Cyrtanthus montanus] haveloose bulblets that re-sprout afterdisturbance. Leopard tortoises arevery fond of Ornithogalum,Crassula and Adromischus. Thehen-and-chickens, Chlorophytumcomosum, forms plantiets on a longinflorescence, that rapidly root andform dense mats. Plectranthusmadagascariensis and P verticil­latus are also mat-forming and re­root rapidly after being trampled.Mother-in-Iaw's tongue, Sansevieriaaethiopica has fibrous leatheryleaves that are browsed by rhinos.The stem and subterranean stolonsare brittle, allowing the leaves breakoff easily, leaving the stolons behindto re-sprout. (Gasteria andAdromischus in contrast have brittleleaves that are adapted to browsingby tortoises.) Have you tried touproot a Sansevieria by pulling it?

The plant breaks off but the stolonsremain behind. Sansevieria leaffragments will rapidly root whenleft in the ground and form plantlets.They are one of our most adaptablegarden plants.

Most of these plants have adegree of succulence so that if theybecome detached from the motherplant, they can survive on storedwater and food. That is why theytransplant so easily and grow sohappily when thrown on therubbish heap! I have seen cycadstems dumped on a rubbish heapstarting to re-sprout after a fewyears. Aloe arborescens, A. ferox,A. africana, and many other aloescan be chopped up and thrown in acorner and will even start floweringand put out new roots a year later,in spite of lying sideways. Similarly,the spekboom (Por~ulacariaafra),thicket spursage (Plectranthusmadagascariensis), ivy-leafedpelargonium (Pelargoniumpeltatuml, red pelargonium(P inquinans) and the zonalpelargonium (P zonale) make good,

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Left. Pregnant onions, Ornithogalum longibracteatum, have brittlebulblets along the stem. When grazed by tortoises, bulblets fall to theground and grow. Above. A leaf fragment of the ox tongue, Gasteria, thatfell to the ground has rooted and formed many plantlets - one of the waysin which a plant exploits abuse and grazing.Opposite page, above left. Haworthias are popular tortoise food.Haworthia cymbijormis is stoloniferous and simply re-sprouts if grazed bythe leopard tortoise. Below left. A young leopard tortoise, Testudopardalis. Right. Rhinos graze the mother-in-Iaw's tongue, Sansevieriaaethiopica. The leaves are firm and fibrous, but brittle at the base of theplant, so they break off at ground level, leaving the subterranean stolonsbehind. Photos: E. Van Jaarsveld.

'A botanical garden in this region is a must! ,

easy to grow garden subjects.My collecting experience from theEastern Cape corroborates this.Plants collected were just placed inpaper packets without any nursing,and after a few days brought backand potted: all of them perfectlysurviving my abuse.

Rainfall in the Eastern Cape isunpredictable and can occur at anytime of the year. Long droughts andflooding are fairly common occur­rences. The plants are tolerant ofdrought but can cope with toomuch water: conditions that oftenoccur in our garden where plantsare often under- or over-watered.These Eastern Cape plants can takeit! (The Eastern Cape succulents arethe only non-local succulents thatthrive at Kirstenbosch. They areplanted in the eastern flank of theconservatory exposed to the fullblast of winter rainfall and yet theygrow, flower and reproduce!)

The Eastern Cape is situatedalong the margin of the subtropicsand its plants are tolerant of lowwinter temperatures as well asextreme heat: a range of 7-40 dc.That is why pelargoniums are easilygrown in Europe, and also in hotdry climates. In contrast, 'Aaronsrod' or wonder plant Tinosporafragosa of the bushveld is a greatsurvivor of disturbance, but heatand summer rainfall are critical forits survival. Another example is the

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baobab (Adansonia digitata).Many garden-fit plants are

relatively tolerant of insect pests.Have you ever seen a spekboom ormother-in-Iaw's tongue (Sansevieria)being eaten by caterpillars, aphidsor grasshoppers? I have grownvarious forms of spekboom for yearsand they are the most insect-free ofall succulent plants! They offerthemselves to larger animals butdeter insect grazers. Agapanthus,hen-and-ohickens, Ledebouriasocialis and Plectranthus madagas­cariensis might have the oddspecialist pest, but on the whole,they are insect-free, a quality thatmakes them ideal for the garden.

Some plants only perform insunshine, others only in shade.Many Eastern Cape plants aretolerant of sun and shade. Whenelephant grazing removes theirshade-cover they have to suddenlyget used to a high light intensityuntil the branches grow back andprovide shade again. This is thereason why Agapanthus cantolerate shade. It flowers best in sunbut can be grown in shade as well.Many Plectranthus will also toleratefull sun although they prefer shade.

The Eastern Cape is the onlyregion in South Africa where mostof the biomes and vegetation regionsmerge - afro-temperate forest, NamaKaroo, fynbos, grassland, thicket,savannah and fragments of

succulent Karoo. The onlyvegetation unique to the region isthe thicket biome. You often find acurious plant combination - aEuphorbia next to a Podocarpusfalcatus, or a tufted mesemb like therare endemic Orthopterum coegananext to an epiphytic orchid likePolystachya pubescens. There is agreat range of soils, and plants aretolerant of a wide soil range, fromthe very fertile valleys where thethickets occur to the mineral-poorquartzitic sandstone soil regions.Consequently, they can grow ingardens with differing soil-types.

Lastly, Eastern Cape plants aretolerant of competition, as they areable to grow in dense plant commu­nities, sharing their habitat withmany other plants.

Why fynbos plants are not garden-fitWe all admire the marsh roseOrothamnus and if it was easy tocultivate we would all have it in ourgarden! Why does an Erica die if wejust walk around it or cultivate thesoil below it? Again the reason lieswithin their native habitat. Just asthe fertile soils of the Eastern Capeand all the factors discussed abovehave produced plants with highoverall garden fitness, the mineralpoor soils of the fynbos producedplants with a low food value thatdid not attract grazing mammals.Instead, fynbos plants have become

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adapted to frequent fires, and this isthe reason they make poor gardensubjects. However, fynbos plantsfrom lowland, strandveld andriverine regions perform better thanmountain fynbos plants, as again,they have adapted to disturbancesother than fire. Think of themesembs, fynbos bulbs andFreylinia for example, and the easewith which they grow. Moleratsplaya vital role in the sandy soils ofthe strandveld and coastal fynbosregions and plants such asBokbaaivygies Dorotheanthus,vetkousies Carpanthea, Trachyandraand many of the bulbs are adaptedto molerat predation. They are alsoadapted to a winter rainfall climate,and no not perform to theiroptimum in summer rainfall condi­tions. Restios are fairly adaptable ­more so than many other fynbosspecies.

Generally fynbos has low overallgarden fitness. They are difficult tocultivate and propagate, and cannottolerate general garden disturbances.

Garden-fit plants elsewhere inSouth AfricaBushveld plants are generally easyto grow in the bushveld. They needdry summers, cool night tempera­tures and wet winters, and theycannot tolerate frost and lowtemperatures, factors that excludethem from growing well in most

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other garden types (i.e. the highveld,fynbos, strandveld, forest and Karooregions). Think of the attractiveimpala lily Adenium multiflorum:it would certainly die if planted inpoor soil and exposed to wetwinters and would need to be grownin a container and taken indoorsduring winter.

Plants from the succulent andNama Karoo regions are easilypropagated and grown but do notthrive in areas with a high rainfall.They die from fungal diseases andcompetition from other fast-growinggarden species. They have a highlocal garden-fitness but low overallgarden-fitness and requireprotection. We have grown Karooplants at Kirstenbosch with diffi­culty in well-drained soil on theMathew's rockery. The cooler condi­tions prevent many from floweringand in the end they die. That is whythe Botanical Society Conservatorywas built so that plants from allover South Africa can be grown in acontrolled climate.

Plants from the afro-temperateand lowland forest regions have afairly high overall garden fitness.They have adapted to disturbanceson the forest floor and can takerough handling. Plectranthus, forestfloor succulents, Dietes, Scadoxus,Clivia, Dracaena and Rhoicissus areother plants with a high overallgarden fitness.

Some plants originating ingrassland also have a fairly highoverall garden fitness and are grownwidely today. With a history ofadaptation to a combination ofgrazing, fire and frost, many of thehighveld bulbs and herbaceousplants are popular garden subjects.These include Kniphofia,Agapanthus, Gladiolus, Scilla,Rhodohypoxis and Osteospermum.

The best recipeThe Eastern Cape has the best recipefor producing plants that cansurvive in gardens anywhere in theworld: a semi-arid climate, unpre­dictable rainfall, disturbances fromtrampling and grazing animals,variable soil and light conditions,and mild to hot temperatures. Wecan safely predict that the chancesof finding other international horti­cultural hits from the Eastern Capeis greater than anywhere else inSouth Africa. The Eastern Cape florashould be protected as a valuablecradle of world garden and houseplants. A botanical garden in thisregion is a must! ®

• See Veld &' Flora 82(2) June 1996 throughto 85(3) September 1999. Many of theseback issues are still available from thePublications Manager at the BotanicalSociety, Private Bag X10, Claremont, 7735.Tel (021) 797 2090, fax (021) 797 2376,e-mail botsocsa@gem.co.za.

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