Colusa County
University of California
Colusa County

Master Gardeners


 Science based solutions for Colusa County's gardening communities.

The UCCE Master Gardeners of Colusa County volunteer's donated 705 hours and made 736 face to face contacts in 2018/19.

Since 2009, we have volunteered 6,475 hours and made 12,154 face to face contacts in Colusa County.


This is what we do!




Need help identifying insects and how to get rid of them? The UC IPM (Integrated Pest Management) has answers!

UC IPM website


July in the Garden

  • You can still plant seeds of annuals: zinnias, marigolds, sunflowers and alyssum will grow and bloom this year.
  • Be sure everything is well mulched for the heat of summer. Water before 10 am to avoid fungal infections and to minimize water loss to evaporation.
  • If you have blackberries in your garden, cut the canes that bore fruit to the ground. Tie up 3-5 of the new canes and fertilize to promote new growth.
  • Cut canna stems to the ground as they finish flowering to encourage new stems to grow.
  • Dig and divide bearded iris that have not been divided for 3 yrs. Cut the foliage on the divisions to 6-8 inches, replanting only new rhizomes and discarding the old rhizomes.
  • You can dig and divide other bulbs after the foliage has died off.
  • Deadhead blooming plants as they finish flowering to promote continuing bloom. Fertilize roses after each burst of blooms.
  • Cut back lavender after flowering to promote a second bloom. You can prune by half to keep the plant in bounds.
  • If you have fruit trees, be sure to pick up dropped fruit to prevent brown rot from developing and leaving spores for future infection.

Asian Citrus Psyllid

Asian Citrus Psyllid is an insect that carries a devastating disease in Citrus trees and there is no cure. The insect and disease is usually detected in home citrus first. Click here to read more about the Asian Citrus Psyllid and the Huanglongbing disease.

The Asian Citrus Psyllid has been found in San Joaquin County.

Click here to read about the Asian Citrus Psyllid from the UCCE Master Gardeners of San Joaquin County.

Click here for Spanish


UC Master Gardeners of Colusa County

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The University of California Master Gardener Program provides the public with UC research-based information about home horticulture, sustainable landscape and pest management practices. The program is administered by local University of California Cooperative Extension (UCCE) county offices that are the principal outreach and public service arms of the University’s division of Agriculture and Natural Resources.

The UC Master Gardener program supports sustainable gardening practices that protect the environment, conserve natural resources, and take into consideration each gardener's lifestyle and goals.


What do UC Master Gardeners do?

UC Master Gardeners are trained to help residents of California become better gardeners. Using a variety of activities such as workshops, lectures, and garden hotlines these volunteers answer questions about home horticulture, sustainable landscaping, and integrated pest management using University of California research-based information.

After their training UC Master Gardeners are qualified to help the public with problems in areas such as:

  • Weed Control
  • Plant Problem Diagnosis
  • Integrated Pest Management (insect and pest control)
  • Soils, fertilizers and irrigation
  • Selecting and caring for fruit and landscape trees
  • Growing annuals, perennials and food crops
  • Lawn care
  • Vegetable Gardening
  • Plant Pathology
  • Composting


Each county develops programs to address local needs. Some typical activities are:

  • Using mass media to disseminate gardening information
  • Teaching workshops, or lecturing on gardening practices
  • Participating in research activities with academics within UC
  • Answering gardeners’ questions via email or helplines
  • Speaking to the public on horticultural and gardening topics
  • Manning county fair information booths
  • Consulting with gardeners to improve their landscape practices


Make an Online Gift to UC Master Gardeners

Find us on Facebook



Garden Advice and Workshops

Second Saturday at the Library

10 to noon

Colusa Library

Garden Chat with the Master Gardeners

Last Tuesday of the month

1-2 pm

Arbuckle Library

Arbuckle Farmers Market

Every Wednesday through summer

3:30 to 7pm

Downtown Arbuckle

Master Gardener Blog

Golden Orbweavers Ignore Biological Rules

A female Trichonephila clavipes (formerly Nephila clavipes) is a giant compared to her small male (below). The research covers a complex pattern of sexual size dimorphism in this group of spiders, family Nephilidae. (Image copyright by Chris Hamilton, University of Idaho)

Size does matter. Have you ever wondered about sexual size dimorphism in the tropical spiders, the golden orbweavers? The females are sometimes 10 times larger and 100 times heavier than their male counterparts. And the webs that the females ...

Posted on Thursday, June 20, 2019 at 4:36 PM
Focus Area Tags: Environment,Innovation,Natural Resources

Do You Know Where Your Pollinators Are?

European paper wasps protecting the nest they're building on the lip of a recycling bin near the Mann lab, UC Davis campus. (Photo by Kathy Keatley Garvey)

It's National Pollinator Week. Do you know where your pollinators are? If you're thinking bees, butterflies, beetles, birds (hummingbirds) and bats, you're correct. But what about European paper wasps (Polistes dominula)? They're pollinators, too, says...

Posted on Wednesday, June 19, 2019 at 4:20 PM
Focus Area Tags: Environment,Yard & Garden

A Case of Survival of the Flittest

Western tiger swallowtail, Papilio rutulus, nectaring on verbena in the Kate Frey Pollinator Garden, Sonoma Cornerstone. (Photo by Kathy Keatley Garvey)

If you visit the Kate Frey Pollinator Garden at Sonoma Cornerstone--and you should, especially during National Pollinator Week--you'll see honey bees, bumble bees, butterflies and hummingbirds, among other pollinators.  Today we spotted a male...

Posted on Tuesday, June 18, 2019 at 5:15 PM
Focus Area Tags: Agriculture,Environment,Innovation,Natural Resources,Yard & Garden
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