June Tips & Events for Santa Clara County

“Gardening imparts an organic perspective on the passage of time.”

~ William Cowper

Monthly Tips

Quiz: Insect Imposter

This common garden insect may be mistaken for a bee as it zips around the garden visiting flowers, but it doesn’t sting. Any idea what it is?

Photo credit: Ying Chen

An insect that looks similar to a bee on a white and yellow daisy

Photo: Adult black vine weevil on a grape vine, Jack Kelly Clark, UC

Insect ID Help

Figuring Out “What’s That Bug?”

When tackling garden bug “problems,” start by identifying insects—not spraying! A proper ID reveals if it’s beneficial or harmful, and knowing what it is leads to better control strategies if needed. While insect ID apps help (mentioned last month), and sending photos to our Help Desk might work, sometimes an ID requires an expert. Santa Clara County Agriculture biologists offer in-person identification for challenging cases—just bring your specimen to their office (call ahead). Remember: identify first, then decide on appropriate action!

Mosaic Viruses

If you see mottled or puckered leaves or strangely-colored, lumpy, or deformed fruit, your squash plant may be infected with a mosaic virus. Several mosaic viruses affect squash and related plants such as cucumbers and melons. Insects such as aphids and cucumber beetles can spread the viruses from plant to plant. Once a plant is infected, there is no cure. Pull the plant and put it in green waste to prevent spreading the virus to nearby plants.

Cucurbit Viruses

Two summer squash - one mottled yellow and green - the other smoothly yellow with a green end

Photo: Summer squash Zephyr: Infected (top) and uninfected (bottom), Sacramento Master Gardeners

Pests without Pesticides

Using pesticides to control garden pests should be your last resort due to the potential harm chemicals can cause to beneficial insects and the environment. An alternative is using physical methods to remove, block, or kill pests with tools or manual techniques. Examples include handpicking insects off plants and erecting barriers like row covers. Copper tape deters slugs and snails, while beer traps attract and drown them. Strong sprays of water can dislodge aphids. Learn more at this UC webinar on June 18: Cover, Smash, Trap: Non-Chemical Methods for Pest Management.

Photo: Forceful water spray to remove aphids, Texas A&M

Non-Chemical Pest Control

Time to Harvest Garlic!

Round purple garlic bulbs and their curly gray roots are attached to their dry - white - stick-like stems

If you planted garlic last fall, you’re getting near harvest time. Stop watering, and after the bottom leaves turn brown, leave the garlic in the ground for a few more weeks. Dig it up in mid-June, being careful not to nick the bulbs. Prep the bulbs for curing by spreading them on newspaper or braiding the tops for hanging. Then, place them in a warm place out of direct sunlight with good air circulation for about 2 weeks. And remember this for next year: plant by Thanksgiving (November), fertilize around St. Patrick’s Day (March), stop watering by Mother’s Day (May), and harvest around Father’s Day (June).

Photo credit: Pixabay

Store, Preserve & Enjoy Garlic

Left: Fire blight

Right: Bacterial blast

Photo credit: Ying Chen

Fire Blight

Bacterial Blast vs. Fire Blight

Oh no, you see blackened blossoms or shoots on your apple or pear tree! But is it fire blight or bacterial blast? Fire blight thrives in warm, moist conditions. It rapidly kills a branch, resulting in a “Shepherd’s crook” shape bend. A light tan bacterial ooze can be seen. Bacterial blast, instead, occurs in cold, moist conditions. Infected blossoms can appear throughout the tree, with unaffected green wood in-between. There is no ooze. Cankers caused by this bacterium are often covered with a papery, flaky bark. Use the UC Integrated Pest Management website to help you manage these diseases.

Bacterial Blast

Quiz Answer: Hover Fly, Look-alike Beneficial

This is a syrphid fly, also known as a hover fly or flower fly. As the name suggests, these flies are often seen hovering in the garden. You can tell them apart from bees as they only have one pair of wings instead of two. Their heads are as wide as or wider than the abdomen, and they have large eyes with very short antennae. Hover flies are one of many beneficial insects you may find in your garden. As larvae, they feast on soft-bodied insects such as aphids, thrips, and mealybugs. As adults, they pollinate various flowers as they feed on nectar and pollen. Look for these insect impostors next time you are in a garden!

A yellow and black hoverfly that looks similar to a bee on a spent daisy flower

Photo: Narrow-headed marsh hover fly, Ying Chen

Hover Flies: Beneficial Insects

More June Tips and To-Dos

For more gardening tips and to-dos, visit the monthly tips archive on our website. It is perfect for browsing, and while you may recognize some of the content, you’re sure to find something new. It starts with to-dos for the month, just the thing to review before heading out to your garden.

More Tips and To-Dos

Upcoming Events

Our monthly Plant Clinic Online is an opportunity to chat with a Master Gardener via Zoom to diagnose a plant problem. You can also listen and learn while other people ask questions. It takes place on the second Tuesday of the month (June 10) from 7 to 8:30 pm. Priority will be given to questions that are emailed in advance; instructions are in the Zoom registration confirmation. Registration required .

PADG Grow Your Best Summer Vegetables, Saturday, June 7, 10 am–noon, Palo Alto Demonstration Garden (PADG), 851 Center Drive, Palo Alto

PADG Open Garden Saturdays, June 7, 10:00 am–noon, Palo Alto Demonstration Garden, 851 Center Drive, Palo Alto

STDG Plan Now for Growing Your Asian Vegetable Garden, Saturday, June 7, 1–2:30 pm, Sunnyvale Teaching and Demonstration Garden, Charles Street Gardens, 433 Charles Street, Sunnyvale

The Monarch Butterfly Crisis: What’s Happening and How You Can Help, Tuesday, June 10, 6:30–7:30 pm, Mountain View Public Library, 585 Franklin Street, Mountain View

Companion Planting: The Three Sisters Method, Tuesday, June 10, 7–8:30 pm, Saratoga Library Community Room, 13650 Saratoga Avenue, Saratoga

Plant Clinic Online, Tuesday, June 10, 7–8:30 pm, Online

Healthy Soil, Saturday, June 14, 10 am–noon, McClellan Ranch Preserve, Community Garden, 22221 McClellan Road, Cupertino

MCP Growing Your Own Cut Flower Garden, Saturday, June 14, 10–11:30 am, Martial Cottle Park, 5283 Snell Avenue, San Jose

PADG Open Garden Saturdays, June 14, 10:00 am–noon, Palo Alto Demonstration Garden, 851 Center Drive, Palo Alto

Introduction to Growing CA Native Plants, Saturday, June 14, 10:30–11:45 am, Willow Glen Branch Library, 1157 Minnesota Avenue, San Jose

Cover, Smash, Trap: Non-Chemical Methods for Pest Management, Wednesday, June 18, 12–1 pm, Online

PADG Open Garden Saturdays, June 21, 10:00 am–noon, Palo Alto Demonstration Garden, 851 Center Drive, Palo Alto

Growing Your Own Cut Flower Garden, Saturday, June 21, 11 am–12:30 pm, Milpitas Library, 160 North Main Street, Milpitas

PADG Open Garden Saturdays, June 28, 10:00 am–noon, Palo Alto Demonstration Garden, 851 Center Drive, Palo Alto

Vegetables You Can Start from Seed Now, Saturday, June 28, 11 am–12:30 pm, Tully Community Branch Library, 880 Tully Road, San Jose

PADG Open Garden Saturdays, July 5, 10:00 am–noon, Palo Alto Demonstration Garden, 851 Center Drive, Palo Alto

Plant Clinic Online, Tuesday, July 8, 7–8:30 pm, Online

Check our calendar for the latest schedule of events. Videos of many past presentations are also available.

About Us

University of California Master Gardener volunteers promote sustainable gardening practices and provide research-based horticultural information to home gardeners. Visit our website for more information including:

More Monthly Tips
A complete list of Upcoming Events and Classes
Extensive Garden Help
Videos of garden tips and past online presentations

Have a gardening question? Ask us. We’re here to help!

Connect With Us