I have 2 wysteria that I grow over garden arches. They have been in for years and this year, one of them had 4 buds on. However, the buds didn't develop and all of them just fell off. I asked the gardener at the local garden centre what causes it and was told I must not water the plants. I had the same problem last year with a lupin. Does anyone know if this is correct, could stop watering the wysteria but lupin needs water.