Creating a Beneficial Insectary Landscape
By Tulare-Kings Counties Master Gardeners
6:47 am,
November 6, 2024

Would you like to cure your dependence on insecticides for pest control forever? There are pest control methods that do not involve killing the “good guys.” Why not create a “beneficial insectary” in your landscape? A landscape insectary incorporates flowers, herbs, and native plants that provide food such as the pollen from poppies and nectar from many Salvias for beneficial insects.

The “good guys” or beneficial insects include damselflies, dragonflies, praying mantis, assassin bugs, minute pirate bugs, spined soldier bugs, lacewings, ground beetles, ladybugs and many more. Look closely at the aphids on your roses and you will most likely see one or more beneficial insects trying to eradicate them. Don’t run for the bug spray! Give the good guys a chance to perform their service.

It may seem a little scary to purposely grow plants for the bugs, but these critters will not be very noticeable as you go about your business in the garden. The good or beneficial insects, spiders, lizards, frogs, and hummingbirds you attract will help win your war against the bad bugs that suck the life out of your flowers, fruits and vegetables. They will also assist with pollination in your garden.

An insectary can be created on small or large lots in the city, or a three acre garden in the country. It is important to cut back or eliminate the use of most harsh broad spectrum insecticides and allow the beneficials to multiply. It won’t happen instantly, but keeping the right flowers and plants blooming in your gardens will attract and provide habitat for a variety of “bad bug” predators and parasites.

Here is a partial list of Insectary plants recommended by the magazine “Organic Gardening.”

Bachelor’s buttons or cornflower (Centaurea cyanus): This plant’s leaves release nectar even when the flowers are not blooming. This nectar is highly attractive to flower flies, ladybugs, lacewings, and beneficial wasps. Sow easy-to-grow bachelor’s buttons seeds directly in the garden in fall or early spring; plants usually reseed energetically and volunteers come back every spring, so you need to have room or else cultivate them out. They do grow tall and tend to fall over, so they also benefit from staking.

Sweet alyssum (Lobularia maritima): This low-growing annual freely reseeds and spreads within a garden. It is available in seeds or bedding plants in white, purple and a white/purple combination. It is very fragrant and is great for edging pathways or companion planting with roses or vegetable beds.

Fennel (Foeniculum vulgare): Long-lasting fennel flowers are extremely attractive to all nectar-feeding beneficial insects, and the feathery green or purple foliage looks wonderful in spring and early summer. Fennel is a host plant for the caterpillars of the Anise Swallowtail Butterfly. The seeds and leaves are also eaten by humans, and are excellent in salads (leaves) or spaghetti sauce (seeds). The plants grow about 5 feet high and are perennial in zones 6-9.

Pussy willows (Salix species): Willows are especially valuable because they produce pollen very early in the spring, when many beneficials are just emerging. Pussy willows are super-easy to grow and fun to cut for flower arrangements. Most garden centers carry pussy willows in spring.

Ornamental grasses: All clump-forming grasses provide excellent summer shelter and overwintering sites for ground beetles, ladybugs and other beneficials. Studies in England found more than 1,500 predators per square yard in grass-covered “beetle banks” planted in arable fields.

Corn tassels: Corn tassels are the male flowers on a corn plant and they produce large amounts of pollen that is a nutritious protein source for many beneficials. Think of corn as a very fast- growing, tall ornamental grass. The ‘Japonica’ variety has green, white and pink variegated leaves. You will want to put this tall plant at the back of your garden. Seeds are available at various online sources.

Flowering plants: Other pollen and nectar producers that are recommended and do well here are: Asters, angelicas, blanketflowers (Gaillardia), California poppy, candytuft, catmints (Nepeta), carpet bugleweeds (Ajuga), coneflowers (Echinacea), coreopsis, cosmos, crocus, dill, feverfew (Chrysanthemum parthenium), garlic chives, lavenders, lobelia, Mexican sunflower (Tithonia rotundifolia), milkweeds (Asclepias), peonies, pincushion flower aka sweet scabiosa, and sunflowers.

There are many plants to do the job, so pick six or seven (or more!), incorporate them into your flower beds and vegetable gardens, and then take note of the variety of predators you attract. Not only do a variety of diverse planting help improve soil health, but pests and disease is less likely to spread rapidly compared to a garden with only one or two varieties of plants. Variety is the spice of life in the garden—the more plant species you have, the more diverse insects will be attracted.

This column is not a news article but the advice of the writer and does not reflect the views of Mid Valley Times newspaper.

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Tulare-Kings Counties Master Gardeners