CONSERVATION

Blooming Beautiful: An introduction to South Africa’s winter rainfall bulbs

APR 5, 2020

Unparalleled Diversity

Above: Autumn flowering of Brunsvigia bosmaniae flowering en masse just outside Nieuwoudtville.

South Africa’s winter rainfall zone is home to one of the richest assemblages of bulbous plants on Earth, comprising more than 2 100 species. From the succulent Karoo of the Richtersveld to the fynbos of the Cape Peninsula, this area encompasses a diverse range of ecosystems unparalleled in few other parts of the world.

Waterwise Beauties

Above: Moraea gigandra blooming in cultivation at Kirstenbosch National Botanical Gardens.

Many of these stunning bulbs are very easy to grow, bringing spectacular blooms to the indigenous garden. They are highly waterwise as a result of their summer dormancy, requiring no water when this precious resource is most in demand. Here on the BotSoc Blog we take a look at a few of the more easy to grow genera suitable for the novice bulb grower.

The Genus Freesia

Known the world over for their elegant blooms and exquisite fragrance, Freesia need little introduction. They are a member of the Iridaceae family with 16 species in the genus from the southwestern Cape to tropical Africa. Freesias like to be grown in a sunny or lightly shaded position in a light, slightly acidic growing mix of potting soil and coarse river sand.

Plant the corms during autumn at 2-3cm in depth. Water heavily once and then around twice weekly once the shoots appear. Freesia alba is one of the easiest species to grow. Freesia caryophyllacea is known for its heavy scent and yellow and white blooms.

The Genus Lachenalia

Above: Lachenalia quadricolor flowering at one of its last remaining habitats on the Cape Flats.

Coming in a stunning range of colours from yellow to turquoise, Lachenalia are some of the most no nonsense bulbs one can grow. The genus is endemic to Namibia and South Africa with a total of around 120 species, most of which are winter growing. They grow best in pots in a sharply draining growing medium of coarse river sand with a 5cm layer of compost in the bottom of the pot.

Bulbs should be planted in the autumn 1-2cm below the surface and after an initial drenching, should not be watered again until the new shoots appear. Try growing Lachenalia quadricolor, easily recognised by its traffic light coloured blooms. Lachenalia flava with its deep yellow blooms is just as easy and rewarding. Hailing from the West Coast, the turquoise blooms Lachenalia viridiflora are hard to miss.

The Genus Moraea

Above: Critically Endangered Moraea aristata in bloom.

Members of the genus Moraea are also known for their spectacular blooms that come in a myriad of different colours. Quite a number of species originate from lowland renosterveld and have become highly threatened in the wild due to habitat loss from transformation for agriculture. The majority are relatively easy to cultivate however. All the winter growing Moraea enjoy a sharply drained growing medium and to be drenched two to three times per week during the growing season.

The most prized in cultivation are the Peacock Moraeas. One of the easiest species to cultivate is Moraea aristata, which is Critically Endangered in the wild having lost most of its original habitat underneath Cape Town’s Southern Suburbs. Coming from renosterveld vegetation in the Overberg, Moraea elegans also has very striking blooms.

The Genus Nerine

Left: Nerine sarniensis in bloom at Harold Porter National Botanical Gardens, Bettys Bay, Overberg.

Coming into bloom during autumn when little else is in flower in the Cape, Nerines are another highly rewarding bulb genus to grow. They grow well both in containers as well as in rock gardens and herbaceous borders.

In autumn they should be given an initial drenching of water to stimulate flowering, but then should not be watered again until the leaves emerge later in the season. Thereafter they should be watered weekly.

Nerine humilis produces attractive pink blooms. Nerine sarniensis has perhaps some of the most spectacular flowers of the genus, producing large glistening red or pink flowers.

The Genus Watsonia

Above: The dwarf Watsonia coccinea comes in a variety of different flower colours.

Members of the genus Watsonia are ideal for planting en masse in the garden for spring and early summer displays. There are also some smaller members of the genus that are better suited to container growing. They should be planted in full sun in autumn at 2-5cm in depth depending on the species and size of the corms. Watsonia borbonica is one of the larger species and does well planted en masse. The diminutive Watsonia coccinea has a variety of different colour forms, growing well in deep pots.

Further Reading

Duncan, G. (2010) Grow Bulbs, Kirstenbosch Gardening Series, South African National Biodiversity Institute, Cape Town, South Africa.

Manning, J. Goldblatt, P. Snijman, D. (2002) The Colour Encyclopaedia of Cape Bulbs, Timber Press, Cambridge, United Kingdom. ISBN 0-88192-547-0.