Converting a vegetable garden to drip irrigation conserves water. (Photo: Jeannette Warnert)

Tasks

• Use a 3-inch layer of mulch around trees and shrubs to retain moisture, suppress weeds and cool soil temperature. Keep mulch several inches back from the base of trees or shrubs to prevent damage to the trunk.
• If oakworms, redhumped caterpillars, or cabbage loopers are present, spray with Bacillus thuringiensis kurstaki (Btk). Repeat every 7 to 10 days for several weeks as a preventative measure.
• Spray aphids with insecticidal soap or blast with a strong spray of water.

Pruning

• Remove suckers on roses and fruit trees.
• Prune and shape camellias, azaleas and hydrangeas after bloom.

Fertilizing

• A little used more often is better than a lot at one time. Follow package directions for specific plants.
• Do not fertilize plants during hot spells.

Planting

• Spring planting season is over. Anything planted this month will need careful watering.
• If you missed planting eggplants, melons or peppers, plant now and keep them moist.
• Propagate geraniums and other soft wood perennials from cuttings.

Enjoy now

• Annuals and perennials: alyssum (Lobularia), maiden grass (Miscanthus), cup flower (Nierembergia), beard tongue (Penstemon), rose, pansy (Viola).
• Bulbs, corms, tubers: tulip, Watsonia.
• Trees, shrubs, vines: snowberry (Symphoricarpos), star jasmine (Trachelospermum).
• Fruits and vegetables: snow peas, squash, strawberries, Valencia orange.

Things to ponder

• Control scale with insecticides or summer horticultural oil. Repeat in June if necessary.
• This season, consider installing drip irrigation to provide for plants without using more water than necessary.

Propogate geraniums and other soft wood perennials this month. For instructions, see the link at the end of this post. (Photo: Pixabay)

Tasks

• Check drip and sprinkler systems – clean filters, check emitters, fix leaks and re?set timers.
• Watch for Western grapeleaf skeletonizer. Use Bacillus thuringiensis (Bt) to control.
• Control gophers and moles with traps, baits, or fumigation.
• Clean up drying vegetation within 30 feet of structures for fire prevention.

Pruning

• Remove spent lilac flower clusters just above points where leaf buds are forming.
• Hedges grow vigorously this month. Trim lightly every 2 or 3 weeks to maintain size and shape. Heavy pruning exposes the interior to sunburn.
• Thin apples to one fruit per cluster.

Fertilizing

• A little used more often is better than a lot at one time.
• Fertilize almond, apple, cherry and plum.
• Fertilize citrus.

Planting

• Spring planting season is over. Anything planted now will need careful watering.
• Fruits and vegetables: cucumber, eggplant, okra, parsley.

Enjoy now

• Annuals and perennials: California poppy (Eschscholzia), blue marguerite, coral bells (Heuchera), iris, sweet pea (Lathyrus), Texas ranger (Leucophyllum).
• Bulbs, corms, tubers: harlequin flower (Sparaxis tricolor).
• Trees, shrubs, vines: cistus (rock rose), rose.
• Fruits and vegetables: butter lettuce, peas, spinach.

Things to ponder

• This is the month to propagate geraniums and other soft wood perennials from cuttings.

Cell packs of peppers, squash, tomatoes and eggplant can still be planted. Make sure they get enough water and do not dry out. (Photo: Flickr, CC BY-NC 2.0 DEED214)

Tasks

• When using herbicides for weed control, spray on a calm day and protect plants by shielding them with a large piece of cardboard.
• Learn to use the ‘Season Adjust' feature on your controller to make irrigation adjustments easier.
• Apply mulch to plantings for water retention. Mulch should be 3 to 4 inches thick. Don't allow mulch to accumulate against stems or trunks of plants.

Pruning

• Shape spring-flowering shrubs after bloom.
• Take 4-inch soft wood cuttings to propagate perennials, such as chrysanthemum, azalea, marguerite, lavender, aster and geranium.

Fertilizing

• Feed vegetables and lawns, but use care with lawns, as nitrogen encourages lush growth that requires more water.
• Fertilize deciduous fruit and nut trees with one third of the annual amount of fertilizer needed.

Planting

• This is the end of the spring planting season. Many annuals and vegetables can be planted from seed or transplanted. As temperatures rise, water new plantings.
• Perennials: coneflower (Echinacea), beard tongue (Penstemon), gloriosa daisy (Rudbeckia), plant from seed.
• Bulbs, corms, tubers:  fairy lily (Zephyranthes).
• Fruits and vegetables: corn, pumpkin, squash, watermelon, plant from seed.
• Trees, shrubs, vines: bottlebrush (Callistemon), cotoneaster, solanum (potato vine).
• Annuals: globe amaranth (Gomphrena).

Enjoy now

• Annuals and perennials: dianthus, twinspur (Diascia), wallflower (Erysimum), California poppy (Eschscholzia).
• Bulbs, corms, tubers: squill (Scilla).
• Trees, shrubs, vines:  Photinia, Spirea.
• Fruits and vegetables: snap peas, turnips, onions.

Things to ponder

• To cover 100 square feet of space with mulch 3 inches deep, you will need one cubic yard of trunk space.
• Use the least toxic chemical – water, insecticidal soap, Bacillus thuringiensis (Bt) or horticultural oils – for pest control.

California poppies growing in sunny areas on the valley floor are now in full bloom. (Photo: Jeannette Warnert)

Tasks

• Pull weeds and hoe often to minimize reseeding.
• After mulching, check to make sure your irrigation runs are watering through the mulch to the correct rooting depth. If not, increase run times.
• Use a strong stream of water to rinse aphids from rose bushes.

Pruning

• Remove dead branches from shrubs.
• Deadhead roses to encourage more blooms.
• Thin the fruit of apricot, peach, nectarine and plum trees to about 6 to 8 inches apart.
• Use trimmings in compost pile or chip and use as mulch.

Fertilizing

• Feed bedding plants with all-purpose fertilizer high in phosphorus.
• Fertilize citrus. Follow directions on the container.

Planting

• Plant summer vegetables at two-week intervals to prolong harvest.
• Perennials: Million bells (Calibrachoa), Lily-of- the-Nile (Agapanthus), alstroemeria.
• Bulbs, corms, tubers: fortnight lily (Dietes).
• Fruits and vegetables: cantaloupe, chard, chayote.
• Trees, shrubs, vines: bougainvillea, violet trumpet vine (Clytostoma).
• Annuals: verbena, lisianthus (Eustoma).

Enjoy now

• Annuals and perennials: bachelor's button (Centaurea), California Poppy (Eschscholzia), godetia (Clarkia), coreopsis.
• Bulbs, corms, tubers: iris.
• Trees, shrubs, vines: oleander (Nerium), Indian hawthorn (Rhaphiolepis indica).
• Fruits and vegetables: cherries, cucumber, grapefruit, green onions.

Things to ponder

• To water hillsides, set emitters on upper side of slope.
• Continue to monitor and destroy slugs and snails.