Gladioli come in an amazing range of sizes, forms and colours, even lilacs and blues. Here we share a few basic tips for planting and growing these stunning plants
1. Most gladioli thrive in well-composted, well-drained loose, sandy to light loamy soils; they dislike heavy clay soils, although some of the ‘species’ gladioli have specific preferences. A sunny position is best.
2. Plant gladioli from the winter-rainfall areas in autumn; plant others in winter through to spring.
3. Plant corms 10–15cm deep; the deeper they are, especially in sandy soils, the less likely they are to topple over. For an informal look, toss your corms on the ground and plant them where they fall; the larger corms need to be about 12–15cm apart. The stub of last year’s flower stalk must be uppermost when planting.
4. Most indigenous ‘species’ from the winter-rainfall areas need water in the colder months especially if planted in the summer-rainfall areas; they prefer to be kept fairly dry in summer to prevent the corms from rotting in waterlogged soil and to ensure a rest period. Conversely those from the summer-rainfall areas need to be kept dry in winter.
5. A few weeks before flowering, give your gladioli a fortnightly feed of a high-potash food like slow-release 3:1:5 or 2:3:4 fertiliser. Repeat this if you intend keeping the corms after flowering.
CUTTING FOR THE VASE
Pick gladioli for the vase when the lowest bud on the flower stalk is open and the next one is showing a little colour; the blooms will open from the bottom up. Nipping out the tip can hasten the opening of buds. If cut when the buds are too tightly closed, the flowers might not open.
When cutting for the vase or removing faded flower stalks, leave sufficient leaves on the plant to produce food for the development of following year’s corm.
Hybrid bulbs will be available from your local nursery in spring. Indigenous bulbs can be obtained by mail order; these plants can also be grown from seed. To find the lesser known species try:
- Grow Bulbs (Kirstenbosch Gardening Series) by Graham Duncan, R230.
- Visit sanbi.org