Managing Animal Pests in Your Garden

By Steve McDermott   Master Gardener

In San Luis Obispo County, our suburban homes rub up against the wilder, normal habitats of our native animal neighbors.  Sometimes we interrupt their natural patterns of survival, and often times add attractive alternatives to their food choices.  Colorful flowers, nubile sprouts, and fresh fruit often become more attractive to native creatures than their normal faire of wild grasses and scarce foliage.  But for the home gardener, the animals may be considered wildlife “pests” that damage pretty plants, edible fruits and tasty vegetables. 

How to manage this inherent conflict is challenging, but not impossible.  Here are a few tips for the backyard gardener. 

Most wild animals feed at night or in the early morning and late evening, so they are not easily seen.  This is especially true of large animals such as deer, raccoons, opossums, and rabbits. The most general advice that can be given about controlling these prowlers is to provide barriers. The largest and most pastoral looking animal, a deer, requires the most effort to block from your garden.  Physical barriers, such as 8-foot fences are required to keep them out of large gardens. Tall, wire-mesh fencing may be used around smaller areas and trees.  Besides physical barriers, there are odor repellants available on the market, although some have limited effects.  Check with your local nursery about deer resistant plants such as Digitalis, Euphoria, Narcissus, Tulipa, Nepeta, and ornamental grasses.  Roses and other thorny plants are not resistant to deer.

Rabbits, skunks, opossums and raccoons are also pests in local gardens.  They, too, need barriers.  Those that climb need tall fences with 11/2 foot unsupported wire above fencepost tops so the animals fall off.  A large dog will generally be a helpful deterrent, as will odor repellents. Random lighting and sprinkler systems will confuse them and cause them to look for easier places to forage.  In all cases, garbage should be carefully stowed away in a container with a tight fitting lid so as to not provide an attractive dining area.  Overgrown vines and ground covers should be trimmed since they are favorite habitats.

The San Luis Obispo County Master Gardeners are having their first Spring Plant Sale. So come and join us in the Garden Of The Seven Sisters for the afternoon on Saturday June 22 from 12:00 pm to 2:00 pm. See you there!

Click link below for flyer!

First steps in setting up an irrigation system

By Christina Muller  UC Master Gardener

What should I know before setting up an irrigation system for my garden?  Katie in SLO

Living as we do in a Mediterranean climate, water is a valuable resource and for some people it may be the largest annual expenditure in the garden.  It makes sense to conserve and apply water as judiciously as possible.  A well-planned irrigation system can accomplish this.

It is important to first study the site.  Consider your soil type since water will infiltrate at varying rates.  For instance, sandy soils hold less water than clay and need more frequent irrigation.  Know which plants are drought tolerant as they may be able to survive on seasonal rains, thus requiring no additional irrigation.  Take into account the root depth of plants; annuals may not need to be watered as deeply as those with longer roots.  Steep sites may benefit from terracing to slow water enough that it soaks into the soil instead of running downhill.  Finally, know that sun, shade, temperature, humidity, and wind impact the amount of water that plants require.

A common concern for gardeners is how to effectively irrigate their lawns.  A well-designed sprinkler system will water evenly without overspray onto sidewalks or driveways.  The “Lawn Watering Guide for California” is a free UC publication athttp://anrcatalog.ucdavis.edu/pdf/8044.pdf .  Gardeners can use this to determine the output of their sprinklers and learn the suggested frequency and duration to water each month of the year.

Another helpful resource is the San Luis Obispo County Water-Wise Landscaping site athttp://www.slowaterwiselandscaping.com/Garden-Resources/ .   In addition to information on irrigation systems, gardeners can learn more about water conservation by mulching and grouping plants with similar needs.

To learn more about setting up a system and to see a demonstration with various irrigation components, attend the Advice to Grow By seminar at the Garden of the Seven Sisters, 2156 Sierra Way, San Luis Obispo, on Saturday, May 18 from 10 am to noon.

I notice moths flying around my oak tree, should I be concerned?  Ann M.  Atascadero

By Andrea  Peck  Master Gardener

The small grey or tan moths that you see flitting about your oak tree are likely the oak moth.  About ½ inch in length with pronounced wing veins, the moths are commonly seen during the fall and summer months. Two to three dozen tiny white eggs are laid on the underside of the leaves; eggs turn pink to brown before hatching. The larva that emerges is known as the California oakworm.

The oakworm, unlike its name, is actually a caterpillar. This small, yellow-green caterpillar has a notably large brown head and dark stripes that run along its sides.  Caterpillars extend to about 1 inch when fully grown. As the oakworm grows, it feeds on the oak tree, silently munching through the leaves. When populations are high, defoliation may occur and can be visually alarming. During warm, dry winters, caterpillars thrive.  Drought conditions may precipitate a third  generation of breeding, feeding and metamorphosis. Mass “balding” throughout neighborhoods and groves may lead to the generally erroneous thinking that “something must be done to save the trees!”

The good news is that action is generally not required. The healthy oak can withstand quite a bit of feeding from these tiny gnawers. On occasion, the oakworm will abandon a defoliated tree in search of other food sources. These tiny herds have been known to scale walls, cross lawns and even sneak inside homes to be found hanging from draperies. Not to worry, these hapless creatures do no harm. When food is scarce, the oakworm may rampage nearby plants.  Despite heavy feasting and the subsequent wear and tear on the plant, the oakworm cannot mature on non-oak species and therefore, seldom poses a permanent threat.

Management of the oak moth begins with proper care of the tree. Pesticide use is generally discouraged even when masses of oak moths appear overwhelming. A healthy tree will naturally attract animal and insect hunters. Birds, spiders and predatory insects all love the sight of your tree brimming with their next meal. Your best bet is to pull up a seat and enjoy the show.