UC Master Gardeners of Riverside County

Desert Events & Updates

MAY 2023

 Helianthus niveus is a species of sunflower known by the common names showy sunflower and snowy sunflower. Learn More

What to Plant in May

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

• Time for house cleaning.

Set out Plants

• Eggplant, herbs, parsley, peppers, tomatoes, all vine crops.

Flowers

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

Vegetables

• Transplant tomatoes, eggplant and peppers as temperatures warm.
• At cooler elevations, transplant lettuce cabbage family, collards and kale.
• Plant cilantro and two week intervals for a steady supply.

Maintenance

• Set out traps for earwigs, slugs, and whiteflies.
• 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 CD’s in fruit trees to help deter birds.
• As spring 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.

Fertilize

• Strawberries (end of May).
• Young fruit trees, if missed in April.
• Cane berries after harvest.
• Rhododendron after bloom.
• Cool season turf grass.
• Roses at bloom start.
• Citrus
• If you did not use slow release fertilizer for summer bloomers. Give them a feeding now.
• Fertilize vegetables monthly.
• Feed indoor plants with slow release fertilizer.

Spray

• 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.
• 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

Common white grubs. The species L to R are: Japanese beetle, European chafer, and June beetle.

• You may be noticing white grubs in your compost piles, lawns, or garden beds. These white, c-shaped critters can be 1/4 inch long or 2 inches long, depending on the species. White grubs are the larvae of some scarab beetles, and though many of them can cause damage to our landscapes, not all of them do. Learn More

UC Master Gardeners are available and hope to see you at these Certified Farmers Markets:

PALM SPRINGS 

Saturday, May 6 & 20 - 8am - 1:00 pm

2300 E. Baristo Rd, Palm Springs, CA, 92264

Corona - Saturday, May 2, from 8:30 am to 12:30 pm, at 480 Corona Mall

Temecula Promenade Mall - Wednesdays, May 10 & 24, from 9:00 am to 1:00 pm, at 40820 Winchester Road (J.C. Penney parking lot)

Vail Ranch HQ - Tuesdays, May 5 & 24, from 9:00 am to 1:00 pm, at 32115 Temecula Parkway (Between Ross and Kohl's)

Riverside Downtown- Saturday, May 13, from 8:00 am to 1:30 pm, Main Street between 5th & 6th

Murrieta - Sundays, May 14 & 28, from 8:30 am-1:30 pm, 2422 Village Walk Plaza (Village Walk Place Shopping Center)

Advice to Grow by…Ask Us!

Have a Gardening Question...Ask our UC Master Gardener of Riverside County Helpline!

Please include as much detail as possible along with any relevant photos that illustrate your problem/question.

This service is free of charge and is provided year-round by UC Master Gardener of Riverside County Volunteers.

Email your question(s) to:

Desert Area: anrmgindio@ucanr.edu

West County: anrmgriverside@ucanr.edu 

Drip Irrigation Workshop - Saturday May 20, from 9am-12pm at 32141 Whispering Palms Trail, Cathedral City, CA 92234. Contact UC Master Gardener, Smoky Zeidel at smokyzeidel@gmail.com for registration information.

Greenbelt Monarch Habitat Volunteer Event Friday, May 19 9am Register

Native Landscapes of Color, Safety, & Water Efficiency

Come explore the wonders of our exclusive California native plants that have evolved with our local climate, soil types, and animals over thousands of years. May 13, 2023 | 10 a.m. Register

Lavender Festival - NEW HOURS IN 2023!

Escape the heat and enjoy the lavender fields at sunset! Over 100,000 lights illuminate the farm at night. Open select days.10600 Highland Springs Ave, Cherry Valley, 92223 CA May 5 - July 23, 2023 5pm - 10pm Lavender Festival

In-Person Information Sessions listed below are Tuesdays from 6pm-8pm:

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May 16 - 2980 Washington St, Riverside, CA 92504

May 30 - Via Zoom

Info Session Link: Information Session Registration

Application Link : UC Master Gardener Application

Interested in becoming a UC Master Gardener of Riverside County? Becoming a UC Master Gardener begins with a personal commitment to education and service to the community. In order to be accepted into the UC Master Gardener Program and earn the title of UC Master Gardener, you must attend an Information Session to learn about our program, submit a written application, and complete an interview with experienced UC Master Gardeners. Feel free to contact Rosa Olaiz at rmolaiz@ucanr.edu for any questions you may have. Visit Website

UC ANR Giving Day will run from noon to noon on May 18-19, 2023.

Your gift helps ensure UC ANR continues to provide essential resources and trusted information to the people of California. Some of the projects funded by recent giving day donations include demonstration gardens and outreach teaching supplies. Gifts of any size will have an immediate impact.. Donate