Garden Tips for May
- Plant warm-season vegetables in prepared outdoor garden beds. Sow seeds successively, every two weeks, to prolong harvest for leafy greens.
- Herbs, annuals, and perennials can be planted now.
- Dahlias and begonias can be planted now.
- Frost-tender plants can be brought outside.
- Mulch around plants to control weeds and conserve moisture. Leave space around the base of perennial plants and trees to prevent crown rot.
- Fertilize summer-blooming flowers.
- Stake perennials.
- For continued bloom, cut off spent flowers.
- Trim hedges; lightly trim azaleas and marguerites for bushier plants.
- As spring-flowering shrubs finish blooming, prune to shape, removing old and dead wood.
- Prune lilacs when flowers have faded.
- Cut back wisteria after blooming.
- Fertilize vegetables. Keep moisture level consistent.
- Apply the last fertilizer for the season to citrus in late May after bloom and fruit set.
- Thin fruit on peaches, plums, and nectarines to help prevent branch breakage and get larger fruit. Thin apples and Asian pears to one fruit per cluster.
- “Summer” prune excessively vigorous sprouts on deciduous fruit trees to slow down their growth; let light into the lower canopy to help keep lower wood alive and fruit within reach.
- Feed lawn with nitrogen.
- Deep-water trees and shrubs. Build donut-shaped water basins to keep water away from trunks.
Pest and disease control
- Continue snail, slug, earwig, and aphid control.
- For codling moth control on apples and pears, attach 4-inch high corrugated cardboard bands around tree trunks in early May. In late May or June remove and destroy bands to kill any larvae and pupae found inside.
- Watch for fire blight blossom and shoot strikes on apples, pears, and Asian pears. Remove new blight strikes weekly on shoots and spurs throughout May. Clean tools with a 10% bleach solution between cuts.
- Check for powdery mildew on grapes; if needed, apply sulfur or potassium bicarbonate when temperature is below 90°.