Fertilize roses with a liquid 20-20-20 solution when flower buds are set.
Monitor roses for insects and diseases. Check daily for black spot, especially in wet weather. Do not handle rosebushes if foliage is wet and infected. Wait until leaves have dried before removing them and spraying.
Monitor roses for rose slugs (small white caterpillars with black heads) and their damage (tissuelike patches on the leaves).
Succulent new green growth is particularly susceptible to aphid attack. Monitor newly planted shrubs, small flowering trees, and juicy perennials for signs of aphids — curled, distorted tip growth. Spray a strong stream of water on damaged foliage to remove pests.