Attract beneficial creatures

Credit: Carolyn Herriot

In summer my garden buzzes with the sound and activity of bees, parasitic wasps and a myriad other beneficials. They play a crucial role in controlling pest populations in the garden and increasing my harvest of fruits, vegetables and flowers through pollination. Of thousands of wildlife species, most are allies, very few foes. Over time I have become familiar with the allies in all stages of their life cycles, as I don’t want to inadvertently destroy them or the delicate balance of insect populations in my garden. Keeping a good identification book handy really helps! (See reference below.)

The key to attracting and keeping beneficials around is to grow a diversity of plants, with a focus on scent, and to provide the essentials of water, habitat and food. TIP: Butterflies and bees prefer the simple blooms of old-fashioned flowers, especially if they are strongly perfumed. Wildlflower meadows fit this bill perfectly.

Ponds or birdbaths can provide water; you can also place shallow dishes around the garden, which will fill up when it rains or when the garden is watered. Water attracts frogs, salamanders and dragonflies and provides an oasis for thirsty insects and birds in hot summers. TIP: Place a large rock or ornamental feature in the pond or birdbath to give winged visitors a place to perch.

Pacific tree frogs thrive in our surrounding Douglas fir ecosystem and are adorable peeping out from decorative dahlias or hanging out on gaillardia blooms. We look forward to the noisy springtime chorus from the marshlands below, which heralds the approach of warmer days (and more frogs). These cute little critters need a source of clean, cool water for tadpoles to develop. They spend the rest of the season in the garden gorging on insects before returning to water to lay their eggs, a new cycle of life.

At the height of the butterfly season in summer, my garden is awash with the beauty of fluttering butterfly wings. Lorquin’s admirals and anise swallowtails are the most prevalent species. The swallowtails lay their eggs on fennel and dill, host plants for larval food. The Lorquin’s admiral needs species of Salix (willow), Populus (cottonwood, poplars), Prunus (cherries), Spiraea (spirea) or Malus (apple) to complete its life cycle.

Dry-laid stone walls or log piles with turf incorporated can attract a wide range of fungi and insects as they biodegrade. These will provide habitat for a range of creatures from snakes to mason bees and bumblebees, all of which like to nest in cavities. By piling up rocks I have created a den for garter snakes, which I always appreciate for being efficient slug predators.

One of the best natural predators for aphids is our native ladybug (Hippodamia convergens). Ladybugs eat aphids in both their adult and larval stage; adults consume up to 5,000 aphids during their lifetime. It’s important to recognize the larval stage of the ladybug, so it is not mistaken for a pest. Larvae look like six-legged crocodiles, dark brown in colour with bright-orange spots on the back of their lumpy bodies. A mature larva can eat as many as 50 aphids a day, and between 200 to 500 aphids in its three-week lifespan. Ladybugs produce up to six generations a year, which accounts for a lot of aphids!

Ornamental grasses provide excellent summer shelter and overwintering sites for ground beetles (which eat slugs), ladybugs and other beneficials. Seedheads of grasses provide useful winter insect habitat.

Gardening with wildlife has opened my eyes to new ways of enhancing the health of my garden. Broad-spectrum insecticides can be fatal to wildlife, but encouraging healthy populations of beneficials in the garden makes it unnecessary to use such products. It’s sad to think how often gardeners overlook the crucial role of wildlife in their gardens, when by simply cooperating with nature, countless hours of toil and worry could be saved.

Plants to Lure Good Guys into Your Garden
(Plants are hardy to the zone number indicated.)

– Achillea filipendulina (fern-leaf yarrow, zone 3) attracts lacewings and ladybugs.

– Agastache foeniculum (anise hyssop, zone 4) has nectar-rich flowers that are very attractive to both butterflies and pest-eating beneficial insects.

– Anthemis tinctoria (golden marguerite, zone 3) attracts ladybugs, lacewings, flower flies, tachinid flies and mini-wasps.

– Borago officinalis (borage) common green lacewings have a strong preference for laying their eggs on borage.

– Centaurea cyanus (cornflower or bachelor button) has extrafloral nectaries, glands that release nectar even when the flowers are not blooming. Highly attractive to ladybugs, lacewings and beneficial wasps.

– Foeniculum vulgare (fennel, zone 5) has flowers that are attractive to nectar-feeding beneficial insects such as parasitic wasps, lacewings and hoverflies. It is also a host plant for the caterpillar stage of the anise swallowtail butterfly.

– Lobularia maritima (sweet alyssum) low-growing annual highly attractive to syrphid flies, the larva of which eat dozens of aphids daily.

– Phacelia tanacetifolia (bee friend) lovely purple-blue flowers irresistible to hoverflies and bees.

– Salix spp. (pussy willow) are especially valuable because they produce pollen early in spring, when many beneficials are just emerging.

PLUS: Iberis (candytuft) is a food source for hoverflies; Nemophila is a food source for syrphid flies. Oenothera (evening primrose) attracts ground beetles; Solidago (goldenrod) attracts parasitic wasps and predaceous beetles. Members of the Umbelliferae family, such as dill, anise, coriander and parsley, have flower clusters easy for beneficial insects to feed from. Angelica attracts lacewings.

Carolyn Herriot owns The Garden Path Centre for Organic Gardening in Victoria (www.earthfuture.com/gardenpath) and Seeds of Victoria. She is author of A Year On The Garden Path: A 52-Week Organic Gardening Guide (ISBN 0-9738058-0-3)