By Martinm
France 
We have a rose bed which is subject to black spot. We have just covered the whole area with horticultural plastic in an attempt to inhibit reinfection, but it looks unpleasant, so we'd like to cover the plastic in some way. Would using a vegetable matter such as wood bark or coconut fibre be subject to fungal infection. If not, would some kind of gravel be better?
Martin Milnes
27 Mar, 2010
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Bark or any other mulch will do. You must clear away all fallen leaves next autumn and top up the mulch to prevent re-infection. Smothering any leftover leaves with new mulch is a good way to deter blackspot. You could also plant some hardy Geraniums around the roses to brighten up the bed.
30 Mar, 2010