Posted: 07/10/2013 at 14:58
As all your plants are in pots they are entirely dependent on your for food and water. In summer, most pots need watering every day to keep the compost from drying out and stressing the plants.
Stressed plants succumb to disease and pests. Happy, well fed and watered plants fight them off. Water them well now, soaking them in a bucket if you can until no more bubbles appear, and then keep them watered till they go dormant. Stand them on pot feet or bricks for the winter so they don't sit in a puddle.
The white stuff is mildew and, as stated above happens to stressed plants. Mint likes moisture and shade form midday sun. Dicentra does tend to die back earlier than many plants. Honeysuckle and buddleia can be cut back next spring as new growth starts and then will need a good feed of slow release food to last them for a few months plus regular weekly liquid feeds of rose or tomato feed to keep them growing and flowering well.
Bin or burn any affected foliage you remove. Do not compost it.