Plant Doctor Archive

Unsightly irises

Please could you help me. Three years ago I was given some iris tubers. They have grown very tall and produce beautiful white flowers for quite a short time, then I am left with a mass of rather unsightly tall leaves. They get blown around in the wind and also take up too much room. I do like the flowers in their season, though. Can they be cut down to say 20 cm until next year or should I lift them out altogether? If I lift them, when should I plant them again?

Unfortunately, irises are only short-lived flowers, but worth the effort. When bulbs have finished flowering, food is taken from the leaves and stored in the bulb for the next season's flowering. If you reduce the foliage, you reduce the size of the bulb, which affects next season's flowering. The foliage can be cut back a little, by say a third, although I would avoid doing this if possible.

Are these bearded irises or Dutch/Spanish irises? If they are Dutch/Spanish irises, just bend the foliage over and tie with a rubber band until the foliage has browned off and can be removed. This should hide unsightly foliage.

If they are bearded irises, I wouldn't cut the foliage. Divide bearded irises every 3-4 years, which may help. Foliage can be cut back when dividing bearded irises. Replant straight away.

A clever way to hide foliage is to plant around bulbs so that annuals or perennials are coming up to hide the foliage as it dies down.

Yes, Dutch/Spanish irises can be lifted and stored in a cool, dry place with the foliage intact until it browns and dries off. Remove the dead foliage and store the bulbs in a net bag or stocking in a cool, dry place. Replant in autumn.

Advice by Dr Dan Blanchon from Unitec's Diploma in Sustainable Horticulture and Bachelor of Resource Management.

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