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| Do you have a gardening question? The UC Master Gardeners of Santa Clara County can help. Our volunteers are part of the University of California’s Cooperative Extension program and we are trained to use research-based information to educate our fellow residents on sustainable gardening and landscaping practices specific to our area. Our monthly “Ask a Master Gardener” column will answer your questions and offer tips. Have a question? Email lifestyle@embarcaderopublishing.com. |
Beautiful white Easter lilies are normally everywhere this time of year – in nurseries, on Easter dinner tables and in churches. How do they all come into bloom every year just in time for the moveable Easter holiday? The blooms are forced in commercial growing operations with greenhouses carefully controlled for temperature, light and moisture. Ninety-five percent of the bulbs are started in 10 farms along the California-Oregon border. After Easter, you can plant them outdoors in moist, well-drained soil with partial sun. Their natural cycle will lead to blooms closer to June in subsequent years.
But be careful if you have cats – all parts of lilies are highly toxic to cats.
April gardening tips
Refresh and reuse soil from last year’s containers
If you’re getting out the containers you used to grow last year’s vegetables and ornamentals, you may wonder if you can reuse the soil in them. The answer is yes, you can reuse the soil, with some refreshing. Start by loosening the soil and removing old plant parts. Then, add additional potting mix and some compost. The fresh material will add nutrients and organic matter for the next round of planting. Do not reuse the container soil if there have been problems with disease, insects or weeds. Pathogens, insect eggsmand weed seeds can remain in the soil even after a plant is removed. Here’s more information on how gardeners can reuse or recycle last year’s potting soil.
Cut back your citrus
Once the threat of frost is past (typically March 15), it’s a good time to cut back citrus branches that touch the ground, fences, or other structures. Thin the tree to let more air into the middle. Trim out crossing branches and anything that looks dead.
Mark your calendar for annual Spring Garden Fair on April 26
The UC Master Gardeners annual Spring Garden Fair is coming up on Saturday, April 26 from 9 a.m. – 2 p.m. at Martial Cottle Park in San Jose. We’re busy planting and potting up seedlings, developing talks, readying booths and organizing all aspects of this popular event. We’ll showcase summer gardening with engaging talks and demonstrations. Enjoy our seed swap, repairs at the Repair Café and botanical drinks at the garden-to-glass booth. Shop unique finds at the Green Elephant and explore the One World Kitchen Garden. And don’t miss our big plant sale, featuring tomatoes, peppers, herbs, ornamentals, succulents, and native plants.
Pruning is not needed for fruit productivity, yet it may be desired for size management. Pruning also will help control scale and aphid infestations. If you see ants in the tree, use a sticky goo (such as Tanglefoot) on the trunk to keep them out of the tree. Be sure to apply the goo on top of the tape rather than directly on the trunk. The ants ‘protect’ the scale and aphids. If you see scale (bumps on bark), thoroughly spray with horticultural oil to suffocate them.
Yellowing of leaves is normal this time of year as the iron that keeps the leaves green is chemically unavailable because the soil is too cold. When the soil warms up (over 60° F), check for yellowing. You may not need to apply a nitrogen fertilizer if the new leaves are green.
Refer to the UC Integrated Pest Management website for more citrus care information.
Try your soil’s temperature
The days are getting longer, so it must be time to plant summer vegetables, right? Well, maybe not yet. Even a warm April day doesn’t mean your soil has given up its winter chill. Planting in cold soil results in slow germination, increased risk for rot from damping off, and even stressing plants for the rest of the season.
You can use a soil thermometer to check soil temperature directly. Or use our vegetable planting chart to look up the months best suited for planting. Here’s more information on the right time to plant vegetables.
Check your plants for fire blight
Fire blight is a plant disease named because brown or black leaves, fruit and branches look like they have been burned. It is most common on apple and pear trees. It shows itself in late spring and early summer.
Upcoming gardening events
UC Master Gardener gardening events are happening all over the county this month. Here are some of them, with more are listed on our events page.
Gardening in Our Changing Climate: An Overview of Ways to Respond Tuesday, April 8, online
Building Structures in the Garden: Beds, Boxes, Cages, Trellises Tuesday, April 8, Saratoga Library, Saratoga
Plant Clinic Online Tuesday, April 8, 7–8:30 pm, online
Citrus Planting and Care Saturday, April 12, 10–11:30 am, Guadalupe River Park Historic Orchard, 425 Seymour Street, San Jose
MCP Guided Tours of the Master Gardeners Native Entrance Gardens Saturday, April 12, Martial Cottle Park, San Jose
Growing Natives Garden Tour Saturday, April 12, Santa Clara County
Learn to Successfully Grow Tomatoes Saturday, April 12, McClellan Ranch Preserve, Cupertino
Growing Natives Garden Tour Sunday, April 13, San Mateo County
Low Water Lawn Alternatives Wednesday, April 16, Cupertino Library, Cupertino
Myth or Fact? Debunking Pest Myths Thursday, April 17, noon–1 pm, online
Planning and Planting a Summer Vegetable Garden Saturday, April 19, Willow Glen Public Library, San Jose
Container Gardening Tuesday, April 22, Fremont Unified High School District Adult Education, Sunnyvale, ($60)
Spring Garden Fair – Martial Cottle Park Saturday, April 26, Martial Cottle Park, San Jose
It is spread by insects, rain or pruning. The bacteria enter through the blossoms and travel down the tree. If left unchecked, fire blight can reach the trunk and kill the entire tree. Prune infected branches back to healthy wood, at least 8 inches below visible damage. If the inside of the branch is discolored, you need to cut back even further. Clean pruning tools between cuts to avoid spreading the infection. A less effective method for controlling fire blight is to spray the open blossoms with a copper spray. Planting varieties that are less susceptible to fire blight is beneficial. Always promptly clean up fallen fruit and leaves.
For more information, see the UC Pest Note on Fire Blight.
Would you like to ask a UC Master Gardener about a plant problem? Submit questions to our Help Desk online. You can also attend our Zoom Plant Clinic Online on April 8 at 7:00 pm.
You can also subscribe to our monthly Tips and Events newsletter. San Mateo residents can also find gardening advice on the UC Master Gardeners of San Mateo and San Francisco website.
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