Master Gardener News Blog
By Polly Nelson UCCE Master Gardener
What are parasitic wasps? Sally S. San Luis Obispo
If parasitic wasps seem creepy, their beneficial contributions will convince you to welcome them to your garden. Parasitic wasps (PW) are tiny, non-stinging insects that parasitize their host, mostly other insects that feed on plants. PWs span over three dozen families within the order Hymenoptera. They are much smaller than the large stinging paper wasps, yellow jackets, and hornets commonly found around the yard.
Parasitic wasps are effective managers of aphids and other pests such as mealybugs, whiteflies, scale, and tobacco hornworms. One type of PW specializes in parasitizing only aphids. Tender new plant growth attracts aphids which then attract PWs. Females PWs lay one egg inside the aphid. After egg hatch, the larva feeds on internal tissues and secretes chemicals to transform the soft-bodied aphid into an aphid mummy – a bloated tan to dark brown colored shell. The larva completes its development safely inside the hardened aphid mummy and chews through the shell to create an exit hole. The PW emerges as an adult, mates, and looks for new hosts, all within its 2 to 3-week lifespan. Aphid mummies are easily spotted on plant foliage and are a tell-tale sign that PWs are present and at work in your garden.
Invite PWs to your garden by providing alternate food sources. Plants and shrubs with dense clusters of small flowers, such as Ceanothus and buckwheat, are among those recommended. Other choices include members of the carrot (Apiaceae) family, such as Queen Anne's Lace, dill, cilantro and fennel. Select a variety of plants with different boom periods to maintain a PW population throughout the year. Ant control around plants is imperative to allow PWs to do their jobs. Ants protect and defend honeydew producing pests and interrupt the activities of predators and parasitic wasps. If insecticides are necessary, look for those that pose the least risk to beneficial insects and always follow label instructions.
Welcome parasitic wasps to work with you and for you to improve the diversity and balance of your garden habitat.
For photos and more information on parasitic wasps and biological control, visit www.biologicalcontrol.info
Watershed Garden Workshop
By Leonard Cicerello UCCE Master Gardener
What are the benefits of watershed landscaping? Robert, San Luis Obispo
The premise of watershed landscaping focuses on capturing rainwater and putting it to good use. The financial and environmental benefits are numerous and the satisfaction is great. Rain water that flows across rooftops, sidewalks and driveways, picks up pollutants common to everyday activities. Capturing rainwater reduces the amount of polluted runoff that flows into storm drains and ultimately into streams and other waterways.
To begin, formulate a well thought out plan to capture rainfall and how to use what you capture. Determine the most suitable location in your yard to house rain barrels. Many retailers are equipped to help you get started. Determine the container size you'll need and the quantity. You will need fittings to plumb downspouts into the containers. Consider placing a barrel under the downspout or plumb the downspout into a flat tank under a deck. Utilize gravity flow or install a small pump to send the water out to your landscape.
Evaluate your landscaping to reduce the current water requirement. This may call for swapping out water-thirsty varieties for more drought tolerant choices or even removing that high maintenance lawn. For interest and function, consider hardscape options such as boulders, rock, pavers, or decomposed granite. If you prefer a sparse landscape as opposed to a dense planting, drip irrigation is a wise choice. You can bury half inch drip tubing and connect quarter inch laterals with drip emitters to each plant or tree. Drip emitters range from a half gallon per minute to several gallons per minute which allows you to individualize the water delivered to each plant, further reducing waste.
The UC Master Gardeners are ready to show the public their own watershed garden. What was once a flat unused strip of the parking lot, is now a densely planted example how to slow and redirect the flow of rainwater. Join the conversation on Saturday, May 20, from 10:00 a.m. to 12:00 noon at the Garden of Seven Sisters at 2156 Sierra Way in San Luis Obispo. Please visit our website to register - http://ucanr.edu/sites/mgslo/
By Leslie E. Stevens UCCE Master Gardener
What types of trees would be suitable for my small yard? Karen SLO
Choosing the perfect tree can be intimidating even for experienced gardeners. It's a long-term commitment that has a big impact on your home's appearance, as well as your outdoor enjoyment.
Small-lot owners face the added challenge of finding trees that fit limited spaces. The last thing they need is a huge, overgrown tree littering their yard, while its roots invade planting beds, walls and foundations.
Turns out, they're in luck. As smaller lots have become the norm, nurseries now stock a variety of small trees, as well as large shrubs that can be shaped into tree form. Several varieties of semi-dwarf fruit trees also fit nicely into tight spaces, providing the added bonus of tasty, home-grown fruit.
When selecting any plant, first determine your local growing conditions, including climate, soil type, sun and wind exposure, frost or heat extremes and the tree's water requirements. If planting near a patio or paving, be aware if the tree drops messy fruit, leaves or flowers. And lastly, make sure you are willing to take on regular pruning chores if you choose a shrub and plan to train into a tree.
With this information in hand, visit local botanical gardens or nurseries and investigate books and Internet sources for specific trees that match your needs. Following are examples of small-scale landscape trees grown locally.
Deciduous: Japanese Maple (Acer palmatum) varieties 5-20 ft. - not for hot or windy spots; Smoke Tree (coggygria) 12-20 ft. - takes poor soil; Crape Myrtle (Lagerstroemia) 8-ft. shrubs to 25-ft. tall trees - single & multi-trunked; Flowering Cherry (Prunus) numerous deciduous & evergreen varieties 10-40 ft. high.
Evergreen: Strawberry Tree (Arbutus Marina or unedo); Citrus – most varieties cold sensitive and prefer mild winters and warm-to-hot summers; Pineapple Guava (Feijoa) fruiting tree 15-20 ft.; Strawberry Guava (Psidiumcattleyanum) fruiting shrub or small tree to 6 ft.;Australian Tea Tree (Leptospermum) large shrubs/small trees 10-30 ft.; Melaleuca (ericifolia or linearfoilia) 15-20 ft.; Rhaphiolepis Majestic Beauty – larger variety can be trained as single- or multi-trunked tree 20-25 ft.
Cal Poly Select A Tree: http://selectree.calpoly.edu/search-trees-by-characteristics
City of San Luis Obispo, Street Trees: http://www.slocity.org/home/showdocument?id=3606/h3>/h2>
Gophers And Pets
By Jutta Thoerner UCCE Master Gardener
I have gophers, but don't want to use bait because of my dogs. What else works? Paul D. Atascadero.
If you have identified the rodents in your yard as gophers, two options for control include exclusion and trapping. Exclusion for a raised garden bed requires lining the bottom of the box with hardware cloth or gopher wire before adding soil to the bed. Exclusion is also effective for individual shrubs and trees. Use wire baskets at the time of planting and be sure to allow room for root growth.
Trapping includes live traps and kill traps. Live trapping is not a good option if pets have access to the area. Kill traps for gophers come in several shapes and sizes, and every style has its diehard fans! You can go to your local farm store and spend time doing hands on research until you find a trap you can set yourself.
Here are some tips for trapping success:
Only set traps in fresh mounds. The evening before the first trapping, take a shovel and flatten every mound. The next day, set traps in fresh mounds only.
Use rebar to poke around the mounds. A sudden drop indicates a tunnel passage. Use a small shovel to open the tunnel. Setting two traps facing opposite directions is best. If setting two traps is not feasible, one will do.
Only set traps in an open tunnel. Gophers are clever and will wall off tunnels or create a new branch off the existing tunnel. If you encounter a cleaver gopher, switch to a different type of trap.
Move the traps daily. Any trap that doesn't catch a gopher within 24 hours is a lawn ornament. In which case, remove the trap, flatten mound, find a fresh mound, and reset the traps.
Gophers are busy travelers. You may see 10 new mounds (up to 300 feet of tunnel work) created by a single animal in one night.
To protect yourself and your pets, dispose of dead gopher by wearing gloves, double bag it, and dispose of it in the garbage. Good luck trapping!
By Jackie Woods UCCE Master Gardener
Which Vegetables Are Easiest To Grow? Karen M. Nipomo
Springtime tends to bring out the gardener in all of us. The longer days and warmer weather make us gravitate to garden centers and nurseries in search of inspiration - and something to plant! Vegetable gardens are high on the list of garden projects this time of year so why not plant something that you can eat? More importantly, why not plant something that's super easy to grow?
Thankfully, there are plenty of options. Tomatoes top the list of easy to grow vegetables, especially the small-fruited varieties such as “Yellow Pear” or other cherry tomato varieties. What if space is limited? Consider using hanging pots or size-appropriate pots. Starter plants provide instant gratification because there's no need to fuss with starting seeds. With a little support for their stalks and lots of sun, tomatoes will reward you with a bountiful harvest all summer long.
Loose leaf lettuce is another simple vegetable to grow, even from seed. Whether in a small plot of ground or in a container, lettuce grows quickly, takes up little space and is very easy to harvest: just cut the tops off when you're ready for a salad. Reseed every few weeks and you'll have a steady supply at your fingertips.
One of the most prolific vegetables to grow is squash; specifically, zucchini. Who hasn't been on the receiving end of a few – or dozens – of home grown zucchini? Zucchini tends to do best in warmer soil and they like adequate moisture, too. Another bonus is that you can eat the blossoms.
Other easy to grow options include bush-type green beans, root vegetables such as radishes, beets, carrots and bushy cucumbers which do well in containers. One interesting, though less talked about option for planting vegetables is the ‘regrow' method. Basil, romaine lettuce, green onions, leeks, potatoes, garlic and celery can all be regrown using rooted cuttings (basil) or the root stump. Celery is easy and fun to regrow. After harvesting the leaves and stalks, either root the stump or simply plant it in the soil and watch it grow!
Exciting, isn't it? Let's plant some vegetables!
Looking for more inspiration? Visit http://cagardenweb.ucanr.edu/Vegetables