Plant Doctor Archive

Spots on hippeastrum

CAN you please tell me what is wrong with my hippeastrum 'Razzmatazz'? It's been growing in the garden in a sheltered sunny position, but the leaves all end up with ugly brown spots on them. Would it be better for me to grow it in a pot?

I CHECKED with Paul Hoek of Aorangi Bulb Nurseries and he suggests the most likely culprit is the fungal disease Stagonospora, commonly known as leaf scorch. The form of this disease that affects hippeastrum can also cause leaf spots on daffodils and other related bulbs. Apart from the obvious damage to the foliage, it can also affect the bulb causing weak growth and poor flowering.

If your 'Razzmatazz' flowers reliably each year and the only problem is leaf scorch then I wouldn't transfer it to a pot as it sounds as if you already have it in quite a good spot. None of the fungicides commonly available in garden centres claim to control leaf scorch, but I'd try using one of the broad spectrum types such as Bravo, Greenguard or Fungus & Mildew Spray which should give some protection. Apply a spray soon after the foliage comes through and before any leaf scorch symptoms appear, then again at intervals of 2-3 weeks for a while. The protectant properties of the spray may be enough to prevent damage, and keeping the plant clean for a season may help break the disease cycle.

Reproduced with permission from the former Weekend Gardener magazine. The views expressed here are not necessarily those of the RNZIH.