May Tips & Events for Santa Clara County
"Be like a flower and turn your face to the sun. Kahlil Gibran
Martial Cottle Park Spring Celebration
Martial Cottle Park Spring Celebration
Join us at the Martial Cottle Park Spring Celebration this Saturday, May 6. Come see our demonstration gardens, get your gardening questions answered, learn new tips from our garden talks, and shop for tomato, herb, flower, and succulent seedlings. There will be children’s activities, farm tours, and much more. (View details)

Hours: 10 a.m.–3 p.m.
FREE Admission, $6 Parking
Peach leaf curl symptoms
Peach Leaf Curl
If you have peach or nectarine trees, you most likely are seeing some curled leaves with red puckering on them. This is a fungal disease called peach leaf curl. Many of the affected leaves will fall on their own and be replaced with healthy leaves. A severe case interferes with photosynthesis and weakens the tree. About all you can do at this point is thin the fruit to reduce energy demands on the tree, and make a note to spray with a copper spray next winter. Note that copper can build up in the soil so it is best to only spray occasionally for severe cases.

Photo: UC IPM photo shows peach leaf curl symptoms
Other types of fruit trees do not get peach leaf curl, so if they have curling leaves it is probably due to aphids. You can see the aphids on the undersides of the leaves, sucking the juices from the plants. There are many varieties of aphids that are attracted to certain plants—for example Rosy apple aphids affect apple trees—and while they all have the same general shape, there are many different colors. Horticultural oils and soapy sprays smother the aphids which breathe through their skin. A strong jet of water can also knock the aphids off and provide good control. 

More info: UC Aphids Pest Note
Photos: UC IPM photos: 1. leaf curl caused by rosy apple aphid, 2. potato aphids
Leaf curling caused by rosy apple aphid
Potato aphids
Romaine lettuce bolting
Some cool season vegetables go to seed when temperatures get warm. They are getting ready to reproduce and they put their energy into seed development, at the expense of the parts we like to eat. For example, lettuce becomes bitter and beets become woody. Pinching off the flower heads as soon as they start to appear can buy some time for harvesting the edible parts. A future fix is to look for varieties that are not susceptible to early bolting—look for varieties that are labeled as slow bolting.

More info: Growing Lettuce Year Round
Photo: Romaine lettuce bolting (from UC Davis Good Life Garden blog)
Root bound plant ball on container grown plant
Plant roots need growing space in order to absorb water and nutrients for a plant. If plants are in small pots, they may need to be transplanted to larger containers or raised beds or into the ground. When transferring them, check the roots to make sure they are not circling or root-bound. You can use your fingers to spread soft herbaceous roots when moving the plant into new soil; woody roots may need to be cut along the edges of the root ball.

More info: Repotting Houseplants (University of Alabama Cooperative Extension)
Photo: Root bound plant ball (Virginia Cooperative Extension)

Mowing Height
When the weather gets hot, it is recommended to raise the blades of your lawnmower. If the grass stays slightly longer in the summer, it helps shade the ground and keeps the sun from heating up and drying out the soil too quickly. This reduces stress on the roots and helps conserve water. Different species of grass have different recommended heights to have the healthiest possible lawn.

Photo: scalping a lawn provides opportunities for weeds ( Michigan State University Extension
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Upcoming Events
Mon, May 01, 7:00 p.m.–8:30 p.m., Planting a Native American Three Sisters Garden, Morgan Hill Library, 60 W. Main Ave., Morgan Hill

Sat, May 06, 10:00 a.m.–3:00 p.m., Martial Cottle Park Spring Celebration! A Taste of the Valley of Heart's Delight, Martial Cottle Park, 5283 Snell Ave., San Jose

Sat, May 06, 10:00 a.m.–11:00 a.m., Low-Water Lawn Alternatives, Palo Alto Demonstration Garden, 851 Center Dr., Palo Alto

Sat, May 06, 10:30 a.m.–11:30 a.m., Growing Terrific Tomatoes, Martial Cottle Park, Master Gardener Parcel, 5283 Snell Ave., San Jose

Sat, May 06, 12:00 p.m.–1:00 p.m., Don't Squash That Bug, Martial Cottle Park, Master Gardener Parcel, 5283 Snell Ave., San Jose

Sat, May 06, 1:00 p.m.–2:00 p.m., Gardening with California Native Plants, Martial Cottle Park, Master Gardener Parcel, 5283 Snell Ave., San Jose

Sat, May 13, 10:00 a.m.–12:00 p.m., Your Bee-Friendly Garden, Guadalupe River Park Gardens, 438 Coleman Ave., San Jose

Wed, May 17, 6:30 a.m.–8:00 p.m., How to Fertilize Plants, Calabazas Library, 1230 S. Blaney Ave., San Jose

Wed, May 17, 7:00 p.m.–8:30 p.m., Gardening in Containers, Milpitas Public Library, 160 N. Main st., Milpitas

Sat, May 20, 10:00 a.m.–12:00 p.m., Gardening in a Small Space, St. Louise Hospital Teaching and Demonstration Garden, 9400 Uno No Name Way, Gilroy

Sat, May 20, 1:00 p.m.–2:30 p.m., Blueberries in Abundance, Santa Clara Central Park Library, 2635 Homestead Rd., Santa Clara

Wed, May 24, 7:00 p.m.–8:30 p.m., Attracting More Pollinators to your Garden Year Round, Cupertino Community Hall, 10350 Torre Ave., Cupertino

Wed, May 31, 7:00 p.m.–8:30 p.m., Culinary Herbs, Los Altos Public Library, 13 S. San Antonio Rd., Los Altos
Visit the UC Master Gardener Program website  for additional information including an up-to-date list of events and classes .

Have a gardening question? Contact our Hotline (for Santa Clara County residents).Start by reviewing our plant problem diagnosis tips.

  • Mon-Fri 9:30 a.m.–12:30 p.m., 408-282-3105
  • Fri ONLY 1:00 p.m.–4:00 p.m., 650-329-1356 (Closed Dec. & Jan.)
  • Or send us your question online

The University of California Cooperative Extension (UCCE) Santa Clara County Master Gardener Program volunteers are trained under the auspices of the UCCE. Our mission is to promote sustainable gardening practices by providing up-to-date, research-based horticultural information to home gardeners.

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