Watsonia tabularis
Introduction
Watsonia tabularis has showy summer flowers, attracts Sunbirds and Sugarbirds and is well suited to fynbos gardens.
Description
Description
Watsonia tabularis is a geophyte with a rootstock that is a corm. A corm is a shortened, swollen underground stem with buds on it, that is enclosed by dry leaf bases, called tunics. Watsonia tabularis is evergreen. New leaves sprout in winter and its main growing season is during winter, spring and early summer. The leaves are sword-shaped. Several are produced at the base of the plant, which are 0.5 to 1 m long and up to 40 mm broad at the widest point. They have a prominent midvein and are erect. There are also leaves that arise from the flowering stem, which are only 80 –200 mm long. They wrap around the stem, are inflated and often contain some water. The stems are branched and a dark purplish colour.
The flowers are elongated tubes, up to 45 mm long with flaring lobes, arranged in showy 20–30-flowered spikes up to 1.5 m high, in early summer (Nov.–Jan.). The flower colour is variable, they can be a deep reddish orange, a bright orange, or salmon-pink with paler inner tepals. The plants in the southern Cape Peninsula have flowers that are uniformly orange, whereas those in the northern part of its range have more varied colouration. The seed capsules are large, 20–30 mm long and about 11 mm wide. They split to release 10 × 3 mm winged seeds.
Conservation Status
Status
Watsonia tabularis is a narrow endemic and occurs only on the Cape Peninsula and the adjacent Cape Flats. However, it has a stable population and is not facing any threats. According to the website http://redlist.sanbi.org, checked on 30 September 2015, the conservation status of this plant is Least Concern (LC).
Distribution and habitat
Distribution description
Watsonia tabularis occurs on the Cape Peninsula in the Western Cape. It is frequent on rocky sandstone flats or slopes from Red Hill to Cape Point and occasional from Kalk Bay to Table Mountain. It occurs from near sea level to the top of Table Mountain, at 1 000 m.
Derivation of name and historical aspects
History
The genus Watsonia was named by Philip Miller of Chelsea after his friend Sir William Watson (1715–87), a physician and naturalist from London. This species is named for its type locality, Cape Town’s iconic flat-topped Table Mountain, from the Latin tabularis meaning ‘pertaining to a (flat) writing tablet or board’. The plants in the southern Cape Peninsula were formerly regarded as a separate variety ‘var. concolor’, meaning ‘of the same colour’, because they have flowers that are uniformly orange, compared to the more varied colouration of those of the northern plants. However, Goldblatt in his 1989 revision does not give this variant formal recognition.
Although Watsonia tabularis is common on Table Mountain and in the southern Cape Peninsula, it was largely ignored by botanists and described relatively recently, in 1922.
The genus Watsonia contains 52 species and is found only in southern Africa. They occur in the mountains and coastal areas of the Northern Cape and Western Cape, through the Eastern Cape and KwaZulu-Natal to the Drakensberg in Mpumalanga and Swaziland. Most of them, 34 of the 52 species or 65%, occur in the Western Cape.
Ecology
Ecology
Watsonia tabularis does not need fire in order to flower, but flowers prolifically after a fire, when they can turn the whole mountainside orange or pink. I wouldn’t be surprised if this plant is the reason behind the naming of Red Hill behind Simonstown!
Watsonia tabularis is pollinated by nectar-feeding birds. We know this because the flowers have no scent and are brightly coloured and held up high for the birds to see. They produce copious amounts of dilute nectar. The flower stem is sturdy enough to take the bird’s weight. The flower tube is curved to match the curve, and length, of the bird’s beak. The upper tepals of the flower are hooded and the anthers and stigma are presented just under the hood. The lower tepals are bent back out of the way. When the right bird probes with its beak into the flower to reach the nectar at the base of the flower tube, its face or the top of its head will touch the anthers and stigma and get pollen dusted on it. The bird then carries its load of pollen to the neighbouring plant and offloads some onto that flower’s stigma, while picking up some more pollen from its anthers, and in this way the flowers are pollinated. Sugarbirds and all the local Sunbirds are seen feeding from the flowers of Watsonia tabularis. The pollinator has not been confirmed, but is likely the larger Sugarbird and/or Malachite Sunbird which probe the flowers from the mouth of the tube and come into contact with the anthers and stigma, whereas the smaller Southern Double-collared Sunbird and Orange-breasted Sunbird are frequently seen robbing the flowers, by making a hole near the base of the flower tube to steal the nectar and bypass the anthers and stigma.
Honeybees are also seen visiting the flowers and taking pollen and trying to reach the nectar, although they play no part in pollination.
Watsonia tabularis seeds are light and have a single wing that is about twice as long as the seed. They are dispersed by wind.
Watsonia tabularis rootstock is a corm. It functions similarly to a bulb in that it is a foodstore for the plant, and it allows the plants to survive fires and droughts.
Uses
Use
Watsonia corms are said to be edible but sour tasting, tough and fibrous and are not recorded as being eaten by people. Chacma Baboon and Cape Porcupine dig up and eat watsonia corms on the Cape Peninsula.
Growing Watsonia tabularis
Grow
Watsonia tabularis needs a sunny position in a well-drained, sandy soil, with a pH that is acidic to neutral. It prefers granitic or sandstone soils and is not happy growing in the wind-blown ‘oily’ sands of the Cape Flats, or in alkaline soils. This watsonia is evergreen. Its main growing season is in autumn-winter-spring-early summer, during the winter-rainfall period. It does not die back at the end of the growing season or during the summer. As the outer leaves die off, they can be cut off to keep the plant looking attractive.
Plant the corms in autumn at a depth where the top of the corm is 30–50 mm below soil level. Replant the corms after lifting and do not store them dry. Water well in autumn, winter, spring and early summer, but do not overwater and make sure that the excess water drains away, as the corms will rot in waterlogged soil. It will tolerate summer irrigation provided it is planted in well-drained soil. Feed generously with well-decomposed compost. Watsonia tabularis is tender to half-hardy and can tolerate short periods of freezing temperatures (0 to -1oC).
Watsonia tabularis is well suited to sunny rockeries, terraced gardens, retaining walls, fynbos gardens and water-wise gardens, in the winter-rainfall zone. It makes an eye-catching display when mass planted in the garden, in large groups or clumps in a mixed bed or rockery, and can also be grown in large containers.
Propagate Watsonia tabularis by seed or lift and divide the corms.
Sow seeds in autumn in deep seed trays or seed beds, using a sandy mixture e.g. 50:50 washed sand and fine compost or loam. Fresh seed will germinate in three to four weeks. Allow seedlings to remain in their trays for two growing seasons before lifting and transplanting them. Transplant them in autumn. Flowering can be expected from their fourth year.
Allow the corms to be left undisturbed for at least five years between lifting and dividing. Lift the corms in late summer when they have finished flowering and seeding. Remove any offsets and replant in the autumn. Remove the old corms that stack up underneath the current corm and replant the current one (uppermost one). Do not store the corms dry.
References
- Duncan, G. 2010. Grow bulbs. Kirstenbosch Gardening Series. South African National Biodiversity Institute, Cape Town.
- Du Plessis, N. & Duncan, G. 1989. Bulbous plants of southern Africa, a guide to their cultivation and propagation. Tafelberg, Cape Town.
- Goldblatt, P. 1989. The genus Watsonia. Annals of Kirstenbosch Botanic Gardens Vol. 19. National Botanic Gardens, Kirstenbosch.
- Goldblatt, P. & Manning, J. 2000. Cape Plants. A conspectus of the Cape flora of South Africa. Strelitzia 9. National Botanical Institute, Pretoria & Missouri Botanical Garden, Missouri.
- Jackson, W.P.U. 1990. Origins and meanings of names of South African plant genera. University of Cape Town.
- Smith, C.A. 1966. Common names of South African plants. Memoirs of the Botanical Survey of South Africa No. 35. Government Printer, Pretoria.
- Trinder-Smith, T. 2006. Wild flowers of Table Mountain. Botanical Society of South Africa, Cape Town
Credits
Alice Notten
Kirstenbosch National Botanical Garden
December 2015
Plant Attributes:
Plant Type: Bulb
SA Distribution: Western Cape
Soil type: Sandy
Flowering season: Early Summer
PH: Acid, Neutral
Flower colour: Pink, Orange
Aspect: Full Sun
Gardening skill: Average
Special Features:
Attracts birds
Drought resistant
Good potplant
Edible plant
Feeds honeybees
Horticultural zones
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