Daz

However, many gardeners swear by Epsom Salts. There is some research being done on its regular use in the garden (in America, where the soils are obviously different) but the jury is still out. What is known is that (a) Epsom salts is more effective as a foliar spray (dissolve in water), (b) while initial applications make leaf growth lusher, continued use seems to have less impact and leaf growth reverts to pre use condition, (c) it does seem to improve the size of fruits such as tomatoes and capsicums. It is also recommended that a nitrogen fertiliser is applied at the same time.

I have a huge daphne (which started life as a $2 half-dead from K-Mart) planted in a raised garden bed facing east and backed by an enormous myrtus communis. I can't remember when I last fertilised it and, because of drought and water restrictions over the last couple of years, it hasn't been getting much water either. But it generously covers itself with flowers and perfumes the front garden.

My daphne gets yellow leaves every year (but, dammit, can't remember when) which fall off - no apparent ill effects to the plant. I assume it's just shedding it's older leaves. A couple of my camellias do this as well - at the same time as they are putting out new growth.

I would suggest that if only some of the leaves are turning yellow, don't worry - it's probably just the plant's life cycle. If all the leaves are turning yellow, then there is a problem.

I'd suggest Camellia/Azalea food, a good deep watering, and top off with a thick layer of mulch.