African violet
Also called Saintpaulia ionantha, Usambara violet, Cape primrose relative.
| Light | bright indirect light |
|---|---|
| Water | Every 5 days in the growing season, every 8 in winter |
| Pets | Cats safe, dogs safe |
Source: ASPCA Animal Poison Control, toxic and non-toxic plants list.
The African violet comes from a small area of cloud forest in the Usambara and Uluguru mountains of Tanzania, where it grows in shade on rocky slopes in permanently mild, humid air. It is one of the most bred houseplants in the world, with thousands of named cultivars, and it is also one of the very few that will flower more or less continuously on a windowsill. Botanists moved it out of Saintpaulia and into Streptocarpus in 2012, which is why the old name is still on every label and every society badge.
Light
Ten to twelve hours a day of bright indirect light is what keeps it in flower. An east facing window is close to perfect, and a north window in the northern hemisphere or a south one in the southern works with the plant close to the glass. Direct sun is too much and scorches the soft hairy leaves in an afternoon.
In a dim room it makes leaves and no flowers, and the stalks lengthen as the plant reaches. Growers who want flowers all winter use a simple lamp on a timer, which is where the ten to twelve hour figure comes from.
Water
Water from below. Stand the pot in a saucer of tepid water for about twenty minutes, let the compost draw up what it needs, and tip the rest away. That is roughly every five days in summer and every eight in winter.
The reason is the leaves. They are covered in fine hairs that hold droplets against the surface, and cold water plus light damages the cells underneath, leaving the pale rings and blotches that are the most recognisable complaint about this plant. The marks are permanent, so the leaves have to grow out. Water sitting in the crown causes worse than marks; it rots the growing point.
Feeding and repotting
Feed at half strength every second watering while the plant is flowering, which for a happy one is most of the year, using a feed made for African violets. General feeds are higher in nitrogen and give leaves at the expense of flowers.
Repot annually, in spring, into fresh compost. Unusually, this does not mean a bigger pot. Use a shallow pot about a third the diameter of the leaf rosette, because the plant flowers best crowded, and simply refresh the compost each year. If the plant has lifted itself on a bare neck, set it deeper as you repot so the lowest leaves sit just above the surface.
Grooming
Take off spent flowers and their stalks at the base, and remove any leaf that is damaged or lying on the compost. Suckers, which are extra crowns that appear beside the main one, should be pinched out on a single crowned variety; they divide the plant’s energy and stop it flowering well. They can be potted up as new plants.
Propagation
Leaf cuttings are the classic method and they work reliably. Choose a healthy middle aged leaf, not the youngest and not the oldest, cut it with about three centimetres of stalk, and push the stalk into damp compost at a shallow angle so the leaf blade sits just above the surface. Cover it loosely to hold humidity and keep it warm and bright. Small plantlets appear at the base of the stalk in six to ten weeks, and once they have a few leaves of their own they can be separated and potted individually.
Ailments
Pale rings are water on the leaves. No flowers is light, pot size or feed. A stretched bare neck is too little light and is fixed by cutting the top off and re-rooting it. A soft crown is rot from water in the middle. Powdery mildew follows still damp air. The ledger below has the rest.
Ailments observed
| It will not flower | Not enough light, a pot that is too big, or too much nitrogen. Give it ten to twelve hours of bright indirect light, keep it in a small shallow pot, and use a feed made for African violets. |
|---|---|
| Spots on the leaves | Cold water or droplets left on the hairy leaves in sunlight. Water from below with tepid water and keep the leaves dry. The pale rings are permanent and the leaves have to grow out. |
| Long bare stems and pale new leaves | Too little light, which stretches the stalks and lifts the rosette off the compost. Move it brighter. An old plant with a bare neck can be cut off below the leaves and re-rooted as a cutting. |
| A soft or mushy base to the stem | Crown rot from water sitting in the middle of the rosette or compost kept too wet. Remove affected leaves, let the compost dry more between waterings, and always water from below. |
| White powder on the leaves | Powdery mildew, which follows still damp air. Improve the air movement around the plant, remove the worst leaves, and avoid wetting the foliage. |
Questions from the margin
Why does my African violet have pale rings on its leaves?
Water sat on the leaf. The leaves are covered in fine hairs that hold droplets, and cold water plus light damages the cells underneath, leaving a permanent pale ring. Water from below with tepid water and keep the foliage dry.
Why won't my African violet flower?
Light first, pot size second, feed third. It wants ten to twelve hours of bright indirect light a day, a small shallow pot that keeps it crowded, and a feed made for African violets rather than a general one high in nitrogen.
How do I water an African violet properly?
Stand the pot in a saucer of tepid water for about twenty minutes, let the compost draw up what it needs, then tip the rest away. Never leave it standing in water and never pour over the crown.
How do I grow a new plant from a leaf?
Cut a healthy middle aged leaf with about 3 cm of stalk, push the stalk into damp compost at a shallow angle, and cover it loosely. Small plantlets appear at the base of the stalk in six to ten weeks and can be separated once they have a few leaves.
Filed underPlants that will not poison the cat, Plants for a bedroom
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