Table of Contents
Under construction! Suggestions for additions will be most welcome.
How to grow South African bulbs
and those from similar “Mediterranean” climates
Basic cultivation instructions for winter-growing bulbs
- Potting mix: Equal parts of John Innes No.2 and coarse grit.
- Water: From early September until they start to go dormant in late spring. Keep dry during summer dormancy.
- Light: Maximum possible winter light
- Feeding: South African bulbs need much less fertiliser than other bulbs and do not like much phosphate (that is the “P” in NPK fertiliser figures). Use either a phosphate-free or a low phosphate fertiliser at half strength two or three times a season while in growth.
- Temperature: Safest is to keep them just frost-free in winter, though many would be OK in an unheated glasshouse
There are some very low P fertilisers out there, but when I am short of time, I tend to use half strength tomato food. Paul Cumbleton
Some articles in our newsletter might help:
- Newsletter 6 (https://sabg.tk/_media/newsletter:sabgnews6.pdf) included Terry Smale on cultural requirements of plants from Mediterranean climates
- Newsletter 37 (https://sabg.tk/_media/newsletter:sabgnews37.pdf) reported on a talk by George Elder on “Winter-growing bulbs in cultivation and in the wild
- Paul Cumbleton provided information in Newsletter 15 (https://sabg.tk/_media/newsletter:sabgnews15.pdf) on “A Growing Addiction Bulbs from the Winter Rainfall Areas” and in Newsletter 40 (https://sabg.tk/_media/newsletter:sabgnews40.pdf) on “Growing and propagating South African winter-growing bulbs”
Growing from seed
Terry Smale in Newsletter 6:
Most seeds need a rest period before germination, although a few will germinate straight away. Sow in early September in a cool place such as a shaded cold frame. Just cover the seeds with grit. A fall in temperature at this time of year encourages germination (as well as initiating bulb growth). Germination should occur in four to six weeks. Bring them into frost free conditions with more light when they germinate. Bring the growth on later (presumably in spring?) with a low nitrogen fertiliser.
Paul Cumbleton in Newsletter 15:
Paul grows almost all his plants from seed. Seed is a good way to increase a collection, and some species will flower in two to three years from seed. He suggested sowing in early September in the same compost that he recommended for potting, with grit covering the seeds. They can be placed outside in a cool shady position and should germinate in about six weeks. Then bring them inside and give them more light. When pricking out small plants to give them more room, it can be a challenge to plant several tiny bulbs with long roots into one pot for growing on. Paul found that they can simply be laid on their sides with their roots splayed out, and they will grow on perfectly well.
Paul Cumbleton in Newsletter 40:
To ensure good germination, keep seeds in a warm place such as a living room until you sow them in September, not in the fridge. Or hedge your bets by splitting seed batches into two and keeping half in the fridge to sow the following year. Terry Smale reported that even 25-year-old Gladiolus seeds showed some germination. Sow in 50:50 John Innes and grit, without any fertiliser. Seeds may take about six weeks to germinate, placed outside in a cool spot, but bring into the greenhouse once germinated and before the first frosts. Newly germinated bulb seedlings can look like grass, so be careful when weeding! Prick out after one to two years, depending on whether they are crowded: Paul puts several in each pot for growing on, then larger species into individual pots later. Many South African bulbs can flower quite early, in their third or even second year.
How hardy are they?
- Newsletter 39 (https://sabg.tk/_media/newsletter:sabgnews39.pdf) carries an article on the hardiness of South African bulbs by our chairman, Paul Cumbleton, who used to run the Alpine section at Wisley.
- Newsletter 40 (https://sabg.tk/_media/newsletter:sabgnews40.pdf) includes notes on cultivation and propagation from a talk by Paul at our October 2018 meeting.
- Newsletters 33 (https://sabg.tk/_media/newsletter:sabgnews33.pdf), 38 (https://sabg.tk/_media/newsletter:sabgnews38.pdf) and 42 (https://sabg.tk/_media/newsletter:sabgnews42.pdf) have notes on the South African meadow at Wisley, and no. 42 mentions an article on it in the July 2020 edition of the RHS magazine The Garden, with some species listed in the newsletter. Newsletter 33 also recounts one member’s experiences with S.A. bulbs in his lawn.