Marin Master Gardeners
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Marin Master Gardeners

Marin IJ Articles

The Power of Beneficial Insects and Native Plants

October 16, 2015
Karen Gideon

Every garden, no matter how small, is a habitat for plants and animals and an important part of the greater ecosystem. As you plant and care for your garden, you have a direct impact on the health of the food chain — today and for future generations. It’s widely understood that pesticides are a death knell to a sustainable, healthy garden. Yet drought-stressed plants are often the targets of pests as their resiliency weakens from lack of water. What can gardeners do?

The sustainable approach to pest protection is attracting beneficial insects to our gardens to ward off infestations. These bugs are nature’s pollinators and providers of pest control.

The most publicized beneficial is the bee, which is under duress because of habitat destruction, mites and diseases. But there are many overlooked bugs that work for you in the garden. These include parasitoid wasps so small that you can’t see them with a naked eye. There are native bees that look like flies and syrphid flies that look like bees. Lacewings and beetles literally suck the life out of pests. Spiders are always on the lookout for insects to attack.

They may be hard to see and identify, but in order for you to attract these hard workers to your garden, you need to provide a habitat that is attractive and sustaining.

The key elements of a beneficial habitat are a diversity of flowering and native plants, nesting sites, shelter, moisture and protection from pesticides. If they have these elements, they can continue to do their vital work. For the Marin gardener, this makes plant choice an important piece of the habitat puzzle.

Some gardeners may prefer Mediterranean plants that do so well in our climate. But with drought conditions and limited water, the animals that depend on native plants suffer as well. Planting local endemic species can help insure that native predators and pollinators have the food resources they need in these lean times. Natives are low maintenance and beneficial insects are attracted to native plants; some insects require specific native plants for food and nesting.

When selecting native plants for your landscape, consider clusters of flowers with different sizes, shapes and colors. Some of the tiniest beneficial insects can drown in the nectar of a big flower. Look for native plants like ceanothus, yarrow, California honeysuckle, and asters.

When adding diverse native plants to your existing garden, make a calendar of bloom time so you can have flowers and sustenance for your insects year round. Your habitat should include some water and some moist spots for the bugs. And a few rocks placed here and there offering them a resting place.

You want your beneficial insects to over-winter and nest in your habitat. So don’t be too persnickety about keeping things neat and tidy. Native bees are ground nesters so keep a little patch of bare earth with no mulch. A rotting log can serve as a nesting spot and a pile of leaf litter is home to many.

The home gardener is a powerful part of the ecosystem. This can have a negative impact if someone uses pesticides when they see pests in their garden. It will have a positive impact when you add natives to your garden and provide the basic elements of a beneficial habitat to your garden.

For information on native plants, go to our website at www.marinmg.org. Click on the link called “Plant Showcase” and then on the link called “Native Plants,” or click on the “Gardening Tips” link and further click on “Birds, Bees, Butterflies and other Beneficials”.

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