UC Master Gardeners of Butte County
University of California
UC Master Gardeners of Butte County

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°.


Webmaster Email: support@chicodesigns.com