Rex begonia
Also called Painted-leaf begonia, King begonia, Fancy-leaf begonia.
| Light | medium light |
|---|---|
| Water | Every 5 days in the growing season, every 10 in winter |
| Pets | Cats toxic, dogs toxic |
Source: ASPCA Animal Poison Control, toxic and non-toxic plants list, Rex Begonia entry.
Toxic to cats and dogs if chewed. Listed as toxic to cats, dogs and horses. The soluble calcium oxalates cause mouth irritation, drooling and vomiting, and the tubers are the most toxic part. Keep it where an animal that eats houseplants cannot reach it, and speak to a vet if one does. In South Africa telephone the Poison Information Helpline on 0861 555 777; in the US, the ASPCA Animal Poison Control Center on (888) 426-4435.
The rex begonia is a garden hybrid built from a wild species found in Assam in the 1850s, and nobody grows it for the flowers, which are small and rather dull. The leaves carry silver, burgundy, pink and near black in spirals and bands that no other houseplant matches. It is also the plant in this journal with the most contradictory needs: it wants high humidity but hates water on its leaves, it wants moist compost but rots if the rhizome is buried or the pot stays wet, and it wants light but burns in sun. The way through is a wide shallow pot of open mix with the rhizome sitting on the surface, watering from below, and a humid spot with air moving through it. Get that right and it is a spectacular plant; get it wrong and it collects powdery mildew.
Ailments observed
| White powder on the leaves | Powdery mildew, which follows still humid air around a crowded plant. Improve the air movement, remove affected leaves, and keep water off the foliage. |
|---|---|
| Brown crisp edges on the leaves | Dry air, or a pot that dried out. Raise the humidity with a pebble tray and water more evenly. |
| A soft or mushy base to the stem | Rot from a buried rhizome or wet compost. Repot with the rhizome sitting on the surface and water from below. |
Questions from the margin
Why do my rex begonia leaves go crisp at the edges?
Dry air, nearly always. It comes from humid forest floor and a heated room is a desert to it. A pebble tray, a group of plants or a bathroom all help, and misting the leaves does not, because wet leaves invite mildew.
Filed underPlants for a bathroom, Plants for humid air
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