May Gardening Tips

Garden Maintenance

Set out traps for earwigs, slugs, and whitefly.
Thin pit fruits at or before pit hardening.
Thin apples when ½” diameter.
Mow grass or cultivate soil around orchard to discourage thrips and plant bugs.
Mulch around plants to control weeds and conserve moisture. Be sure to leave a small circle of bare soil around the base of each plant.
Deep water trees and shrubs. Build water basins, but do not allow water to stand against the trunks.
Prepare dahlia bed with rich soil.
For continued bloom, cut off spent flowers.
Hang strips of foil or OLD CDs in fruit trees to help deter birds.
As spring comes to an end, and flowering shrubs finish blooming, prune to shape, removing old and dead wood.
Trim hedges; lightly trim azaleas, fuchsias, bushier plants.
Thoroughly clean debris from ponds, fountains and bird baths.
Check the your Master Gardener Class Schedule.

Fertilize

Strawberries (end of May).
Kiwi - top dress with compost.
Young fruit trees, if missed in April.
Cane berries after harvest.
Rhododendron after bloom.
Cool season turf grass.
Roses at bloom start.
Citrus
Corn – N when knee high.
If you did not use slow release fertilizer for summer bloomers. Give then a feeding now.
Fertilize vegetables monthly.
Feed indoor plants with slow release fertilizer.

Spray: Check the California Backyard Orchard website for current information.

Apples and pears for codling moth: first treatment when pears are ½” in diameter and apples are ?”. For timing use codling moth traps or call Master Gardeners at (530) 621-5512.
For codling moth control, attach 4” corrugated cardboard bands around tree trunks in early May; in late May or early June remove and destroy bands to kill the larvae and pupae found in the cardboard.
Check for citrus scale and control with horticultural oil. Encourage natural enemies and protect trees from ants.
Continue application of sulfur or other fungicide to grapes if damp weather persists.
If needed, apply Tanglefoot around tree trunks to deter ants and other crawling insects.
Pears, except Comice – weak copper spray when in bloom, one to three applications for fire blight.
Check roses for black spot, mildew and rust and spray if needed
Check roses for aphids; control with a strong spray of water or insecticidal soap.

Note: all the effective insecticidal sprays kill bees and other beneficial. Do not spray while trees are in bloom.

Plant Seed

Beans, beets, carrots, corn, cucumber, melons, okra, parsley, parsnip, peppers, pumpkins, radish, all squash, tomatoes.
Annuals
Cannas, lilies, tuberous begonias.

Plant Seed - Greenhouse or Cold Frame

Set out Plants

Flowers

Marigolds, zinnias, snapdragons, sunflowers, hollyhock, dahlias, lobelia, salvia, cosmos.

Vegetables