Answer: In general, wait until the cold weather has browned the tops, then trim them off short. Some, such as dianthus, will have some evergreen foliage. Do not disturb it. Apply several inches of organic mulch around but not over top of the crowns of the plants. In spring, apply a complete fertilizer such as 10-10-10 according to the label instructions. You might also apply compost then if you have some available. Maintain a layer of just a few inches of mulch aroudn the plants to help conserve moisture and keep down weeds.
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