MILDEW is something many of us gardeners could happily live without but there are always plants and periods of weather that seem determined to give the fungus a run for its money. Some plants are more susceptible than others. It’s less challenging with plants that are grown in the ground compared to those permanently placed in pots. Although we have a rather immense clump of bears britches (acanthus spinosus) growing in the nursery garden that is a remnant of the earlier plantings made years ago. Without fail it turns completely white (with the powdery coating of mildew) over the course of a few days every June and July. Some friends who visited the nursery recently commented on what the funky new variety of silver leaved acanthus was...

I’ve always found phlox a tricky customer in August when after several days or even weeks of wet weather combined with mild conditions it can spread like wild fire. The older varieties of phlox seem more susceptible to getting mildew compared to the more modern varieties but often it comes down to the local conditions and how they manifest themselves in your garden. Roses and clematis can also be badly affected, much like the phlox there are certain varieties best avoided. In all scenarios the best remedy is to tackle the conditions as best you can which includes planting in an area that receives at least six hours of full sunlight a day to help keep mildew from developing. Clear the planting area of old mulch or plant debris. For roses space plants 120cm apart and prune older centre canes to allow more air circulation.

Water plants in the morning, and water the soil around the base of the plant rather than watering from the top so the leaves and stems stay dry and less humidity develops around the plant. Do not over feed with liquid or granular fertiliser. Lush ‘forced growth’ is far more likely to be affected.

Remove any foliage that is contaminated and place it in a plastic bag for disposal. Check surrounding plants to make sure the mildew doesn't spread.

Next week: taking cuttings of tender plants to overwinter