Grow Bulbs

68 Pages·2000·5 MB·English

Graham D Duncan
NATIONAL
CAL
3S O T A N
I
INSTITUTE
Acknowledgements
This updated guidewasoriginally published bythe
National Botanical Institute in 1996 as GrowingSouthAfricanBulbousPlants,
supported bythe Indigenous Bulb Association ofSouth Africa, and illustrated by
Jeanette Loedolffand Catherine Handforth. I would liketothankJeanette Loedolff
foragain making her line drawings availablefor publication, and
Lizette Engelbrechtfortechnical support.
Technical editor: Deirdre Snijman
General editor: CarolineVoget
Design: David Davidson, Valerie Phipps-Smith
Gardening seriesco-ordinator: Neville Brown
Published bythe National Botanical Institute, Kirstenbosch,.
Private Bag X7, Claremont 7735, South Africa.
©2000 National Botanical Institute, CapeTown.
No partofthis publication may be reproduced without
the prior permission ofthe copyrightowners.
ISBN 1-919684-26-3
Reproduction by Elements, CapeTown
Printed and bound byTrident Press, CapeTown
Kirstenbosch Gardening Series
GROW
DO
LBS
A GUIDE TO THE SPECIES, CULTIVATION
AND PROPAGATION OF SOUTH AFRICAN BULBS
Text and photographs by Graham Duncan
Line drawings byJeanette Loedolff
Right:Ornithogalumthyrsoides
Below: Watsoniaborbonica
subsp.arderneiatKirstenbosch
inspring
Opposite:Moraeavillosasubsp.
elandsmontana
^
O
<
<
DO
Introduction‘y
Winter-growingspecies\"y
Summer-growingspecies
Evergreen species 41
Propagation4/
Seed
Offsets
Bulbilsand cormels
Division ofrhizomatous rootstocks
Leafcuttings
Careofplants51
Feeding
Pestsand diseases
EurtfierreadingJ6
Usefuladdresses58
Sourcesofsupply 60
Index6)
MAftV GUNN l
NATIONAL BOTANICA institute !
private B 101
PRETORI ll
orrolIQ! IP. OF S
3
4
Left:Sparaxisgrandiflora
subsp.acutiloba
Right:Strumariabarbariae
Below:Geissorhizaradians
INTRODUCTION
South Africa, in particularthewinterrainfall
regionoftheWestern Cape, possesses
oneofthe richestcentresofbulbous plants
intheworld, with over 1 100species, many
ofwhich havecontributed handsomelyto
the international world ofhorticulture.
Duringtheearlypartoftheseventeenth
century, SouthAfrican bulbsfound their
wayto England and Europewhere many
were hybridized and ‘improved’, which
resulted inthe modern strainsofcommon
garden plants like Gladiolus, Sparaxis,
Freesia, Nerineand Agapanthus, to
mentionjustafew. Whilethese hybridized
strains havetheir place in modern
horticulture, manyofthewild bulbous
speciesfrom South Africaareeminently
suited tocultivation.
The popularterm ‘bulbous’ refersto
plantsofageophytic (growingfrom
underground budson specialized stems)
nature, and includetrue bulbs
(eg galtonias, lachenalias), corms
(eg gladioli, watsonias), tuberous
rootstocks (eg bulbines, zantedeschias)
and rhizomatous rootstocks(eg clivias,
kniphofias).
TheSouthAfrican bulbousfloracan be
conveniently placed intothree groups,
iewinter-growing, summer-growing and
evergreen species.
Itshould be borne in mindthata
numberofgenera require rather
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Oranjemund
Winterrainfall
Rainallseasons
BeaufortWest
Summerrainfall
CapeTown
PortElizabeth
CapeAgulhas
specialized cultivationtechniques ThefamilyAgapanthaceae
(eg Cyrtanthus)butthe information inthis Agapanthusistheonlygenus belongingto
publication isaimed at providing ageneral thisfamilyand itisendemic in southern
guidetothecultivation ofourindigenous Africa, where itswide distribution extends
bulbous plants. Foramore detailed
exposition, the readeris referred to
BulbousPlantsofSouthernAfrica:aguide
totheircultivationandpropagation, by
N.M. du Plessisand G.D. Duncan, with
watercolours by Elise Bodley(seefurther
reading list).
Forthe purposesofthis publication,
bulbous species belonging totwelve
differentfamiliesare covered-
Agapanthaceae, Alliaceae (alliums),
Amaryllidaceae, Araceae(arums),
Asphodelaceae (eg bulbinellas),
Colchicaceae(eg Gloriosa,
Haemodoraceae (eg Wachendorfia), WM
Hyacinthaceae (eg lachenalias),
Hypoxidaceae, Iridaceae, Oxalidaceae
and Tecophilaeaceae (cyanellas).
Bulbous membersofthefamilies
Orchidaceae and Geraniaceae
(pelargoniums)are notcovered inthis
aprueblsicoamteiwonhaatstdhiefifrercenutl.tivation requirements " H \ 't•«,
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Left: Tulbaghiasimmleri-
FamilyAlliaceae
Opposite:Agapanthusinapertus
subsp.pendulus‘Graskop’-
FamilyAgapanthaceae
fromtheCape PeninsulaintheWestern dormantduringthecold drywinters.
Capetothe mountain rangesjustsouth of Agapanthusranks amongthe mosteasily
the Limpopo Riverinthe Northern cultivated bulbous plants in mild climates.
Province. Agapanthuswasformerlyplaced Theyare ideal garden and container
underthefamilyAlliaceae. Thisextremely plants, and also makeexcellentcutflowers.
variable genusconsistsoften speciesand
canconveniently be divided intotwomajor ThefamilyAlliaceae
groupsofevergreen and deciduous TheAlliaceae, formerlyapartofthe
species. Theevergreen membersoccur in Liliaceae, isawidelydistributedfamilyof
thewinter rainfall and year-round rainfall whichthe mainly Northern Hemisphere
regions, whilethedeciduousspeciesoccur genus Alliumisthe most important. The
inthe summer rainfall regions, and are majorcentresofdistributionforthewhole
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familyare Mediterranean Europe, Asia,
North and South Americaand southern
Africa. Thesouthern African genera
comprise Tulbaghiaand asingle species
ofAllium. The horticultural^important
genus Tulbaghiaconsistsofabouttwenty
speciesand is noted forthe strong onion or
garlicsmell given offbythe injured partsof
mostspecies. Thereare both evergreen
and deciduoustulbaghias, mostofwhich
areextremelyeasytocultivate. The
evergreen speciesare particularlyuseful
as groundcoversand ascontainer plants in
mild climates.
ThefamilyAmaryllidaceae
Theamaryllidsform avery large groupof
oversixtygeneraand are concentrated
mainlyin southern Africa,
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