Though we appreciate native plants every day, Washington State designates April as Native Plant Appreciation Month. This year’s theme, “Native Pollinators Need Native Plants,” is a mantra to live and garden by. Pollination is just one of many ecosystem services provided by native insects, and while there are many resources published about gardening for pollinators and building pollinator pathways, we should also take a moment to look holistically at supporting all beneficial insects in our garden, for pollination and beyond.
The student-run SER-UW Native Plant Nursery has three beneficial insectaries: raised beds that are home to native plants that provide habitat and food sources to predatory insects. Each plant species present in the bed attracts wonderful pollinators to our beds and to the larger area at the Center for Urban Horticulture to pollinate the surrounding native vegetation. However, the primary purpose of these beds is to practice the biological method of integrated pest management (IPM), which is defined as long-term prevention of pests using ecosystem management.
Anybody who works with plants, in any capacity, probably has had their share of battles with pests. Gardeners often see aphids in their crops, houseplant enthusiasts can complain of fungus gnats, and at the SER-UW Nursery, we see all of the above, and then some! Aphids, white flites, thrips, and rose slugs, to name a few, have all taken residency in the nursery at some point and continue to cause damage to plant foliage and subsequently plant health. Minimizing pest presence in the nursery using cultural practices, such as spacing out plants or water-jetting pests off plants, is only so efficient. The beneficial insectaries attract predatory insects that hunt out these pests, an example of an effective biological IPM method.
These beneficial insectaries create a well-rounded functioning ecosystem in the nursery house. Many predatory insects are pollinators in early life-stages, and use the flowers of native species as a food source; in return, our native species are pollinated and will set seed for greater plant production. Later in life, we find the predatory insects in the hoophouse feeding on pests, decreasing the pest population in the nursery, and therefore decreasing the damage to plant health in the nursery. Here are some examples of predatory insects you may want for your specific pest management needs:
- Hoverfly larvae eat aphids
- Parasitoid wasps may parasitize beetles with wasp larvae
- Ladybugs eat rose slugs and aphids
- Lacewings eat caterpillars.
The plants selected for the beds all have specific purposes, from attracting, feeding, and sheltering insects all year-round. The beds are continuously blooming through summer with a diversity of species of staggered bloom time. Here are some examples of plants native to the Puget Lowland that we keep in our beneficial insectaries and what they provide to insects:
|Kinnikinnick, Arctostaphylos uva-ursi
Provides a woody structure and foliage year-round, as well as late spring flowers and late summer berries, attracting butterflies
|Oregon sunshine, Eriophyllum lanatum
Flowers late spring through late summer, attracts bees and moths
|Yarrow, Achillea millefolium
Provides habitat in bushy foliage, attracts ladybugs, parasitic wasps, and hoverflies
|Nodding onion, Allium cernuum
Attracts bees and butterflies, and sometimes repels bunnies
|Canadian goldenrod, Solidago canadensis
Tall flowers that tower over other ground cover species such as kinnikinnick, attracts parasitic wasps, bees, and hoverflies
|Slender cinquefoil, Potentilla gracilis
Nectar and pollen source, attracts parasitic wasps and hoverflies.
Though some of these insects may seem to be pests themselves, they will prey on our actual garden pests such as aphids, rose slugs, and thrips. And this is all still on top of pollination! Let’s continue to garden for pollinators, now with a complete perspective of what we can provide for pollinators beyond nectar and pollen. We gain only benefits in return, in the measurable outcomes of fewer pests eating our plants. The best way to appreciate native plants is to protect them!