Hydrangea
Also called Mophead hydrangea, Lacecap hydrangea.
| Light | part shade |
|---|---|
| Water | Every 3 days in the growing season, every 14 in winter |
| Pets | Cats toxic, dogs toxic |
Source: ASPCA Animal Poison Control, toxic and non-toxic plants, Hydrangea entry.
Toxic to cats and dogs if chewed. The ASPCA entry is for Hydrangea arborescens, a close relative, listed as toxic to cats, dogs and horses through cyanogenic glycoside, with vomiting and diarrhoea the usual result. Treat this species the same way. 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.
Hydrangeas came out of Japanese woodland, and the woodland floor explains them: dappled light, deep leaf mould, and soil that stays damp all summer. Plant in spring or autumn in the north, and in the dormant winter months in South Africa when deciduous shrubs are moved. The famous colour change is a soil chemistry trick rather than a variety difference. Aluminium is available to the roots in acid ground, and available aluminium turns a pink flowered mophead blue. On chalk it will stay pink whatever you do, and white cultivars stay white in either. The other thing worth knowing is where the flowers come from. Mopheads and lacecaps set their buds in late summer for the following year, so an autumn haircut removes the whole display.
Ailments observed
| Limp, drooping leaves | Simple thirst, which this shrub shows earlier than almost anything else. Soak the root area slowly and it will stand up within hours. Repeated wilting in the same spot means the soil is too free draining for it. |
|---|---|
| It will not flower | Last year's buds cut off in an autumn tidy up, or killed by a late frost. Prune only in spring, taking the old flower heads back to the first fat pair of buds. On mophead types the flowers come from wood made the previous summer. |
Filed underPlants that forgive a beginner
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