Sunday 14 August 2011

The end of busy Lizzies as we know them?

Is it the end of fabulous displays of busy Lizzies like these?
I've been doing a lot of question time roadshows across the country recently, and one question that regularly comes up is: "What's wrong with my busy Lizzies - they're all dying?"

The answer, sadly, is a disfiguring disease that is killing busy Lizzies (impatiens) all over the UK. Impatiens downy mildew is a relatively new disease. It was first discovered in the UK in 2003, but there was never a real problem with it until a couple of years ago. But this year it has run riot in gardens - probably encouraged by the cool, damp summer weather - killing off plants wherever it appears.

Unfortunately, the disease is proving 'difficult to control' on the nurseries growing and supplying the plants, with even approved professional fungicides proving ineffective. This could indicate either the presence of a new 'aggressive' form of the disease or that the pathogen has developed resistance to the fungicides.

For us gardeners, there are no approved fungicides for its control - so there's nothing we can do once it strikes in our gardens.

All this means that it could be the end of the busy Lizzie as we know it - the end of all those massed bedding displays and 'ball baskets'. If the plant nurseries can't control it on their plants - then they won't be growing them, as they don't want to dispatch diseased plants - and if we have no approved fungicides to use at home, once it appears on our plants that's it.

There is one possible ray of hope. The Sunpatiens varieties seem to be resistant to the disease. These plants are bigger and more robust than your common or garden busy Lizzie and it may be this that provides the resistance. They are a hybrid of Impatiens walleriana (regular busy Lizzies) and Impatiens hawkeri (New Guinea impatiens). If you look at the plants, you can see some of each of their parents in them. The flower size is somewhere between both and the leaves are slightly thicker than normal impatiens. So, let's hope these offer some