The Role of Native Plants in Your Garden

Pests can be one of the biggest challenges in vegetable gardening. Aphids feed on a plant’s sap, transmitting viruses. Cucumber beetles decimate crops by spreading bacterial wilt while feeding on flowers and fruit. Cutworms chew through plant stems and quickly destroy entire plants.

Signs of pest damage kick off a quest for solutions now and methods for avoiding problems in the future. Best management practices like scouting, exclusion nets, natural remedies, and even removing insects by hand are all techniques that gardeners employ in this struggle, and rightfully so because these methods can be effective! But native plants can work just as well or more so.

As gardeners, we must remember that our gardens are interconnected to the ecological world. Pests have predators, too. Aphid wasps, ladybird beetles, and lacewing larvae eat aphids. Mason wasps attack cutworms. Green lacewings and assassin bugs wreak havoc on cucumber beetles. 

Why and Where Natives Plants Work

Native plants can be beautiful, but their benefits go far beyond aesthetics. They have co-evolved with other plants, animals, fungi, and bacteria and the climate, light, and soil conditions in habitats and regions. They provide food, nectar, and shelter for many important insects. They play meaningful roles in keeping ecosystems stable.

By selecting and planting native flowers and grasses that attract beneficial (aka pest-controlling) insects, you can bring native bees and other pollinating insects to crops like cucumbers, squash, pumpkins, blueberries, and strawberries.

These helpful insects can be even more effective when you bring them into close proximity to your vegetable crops. Drawing these insects into the garden increases the population and diversity of these valuable assistants.

Placing native plants in or very near your garden—for example, in “pockets” on the edges of a bed or in one or two rows as an insectary strip right through the middle of your garden—improves pest control and your crops’ pollination. Choosing diverse plants with different bloom periods will provide continuous flowering throughout the year. For example, mason bees are present in early spring, whereas bumblebees are present throughout the growing season. Providing an uninterrupted supply of food throughout the year will ensure they are all happy, and you will enjoy the aesthetic side benefit of yearlong blooming flowers.

When choosing native plants, you’ll find that there are numerous options. Some lettuce farmers in California use sweet alyssum to increase the biological control of aphids. Nonnative annuals and biennials like cilantro, dill, and alyssum also grow quickly and attract beneficial insects. However, these plants might not last more than a season or two. Perennial native plants provide insect habitat year after year, with no need to till or replant. They are long-term investments for your garden.

Not just any natives will do—there are a few considerations. Plants set close to crops, such as in beds within the growing area (aka “insectary strips”), should be sturdy-stemmed, cast little shade, and tolerate full sun and hot conditions. Choose plant species that ideally stand 1 to 3 feet tall at maturity; taller plants may cast shade or fall over into the vegetable rows. In general, native plants can be spaced apart from each other according to their size at maturity.

Correct spacing allows them to be dense enough to suppress weeds while giving each other room to grow. Use 12-inch spacing for plants less than 24 inches tall, 18 inches between plants 24 and 48 inches tall, and 24-inch spacing for those taller than 4 feet. (The tallest species may be better suited for pocket plantings around the edges of the garden.) Plant guides and tags also often offer great guidance.

Wonderful choices for wildflowers include golden alexanders (Zizia aurea), nodding wild onion (Allium cernuum), prairie sundrops (Oenothera pilosella), and Virginia mountain mint (Pycnanthemum virginianum).

Why to Plant Native Plants

Plant communities have two equally important parts. The aboveground photosynthetic component—the stems, foliage, and flowers—is obvious. However, the belowground system of roots, symbiotic fungi, and microorganisms is equally important to the community. The structure of root systems is essential to how this underground community functions. For example, wildflowers tend to have a prominent taproot with some side branches or a coarsely fibrous root system. In contrast, grasses tend to have densely fibrous, fine-textured, deep roots that occupy more of the root zone, making them resilient, reliable soil stabilizers.

Because of this structural difference in the root systems, grass communities tend to be more stable and resistant to invasion by weedy species than wildflowers-dominated communities. The diversity and biomass of these root systems improve organic matter, water infiltration, and soil health.

Without question, the most stable herbaceous plant communities contain wildflowers growing within a matrix of grasses typically seen in our native prairies. A good target for native plantings is 20 percent to 30 percent native grasses and 70 percent to 80 percent wildflowers.

In a 30-inch-wide bed that runs the length of a garden, there is sufficient space for two rows of native plants. Group plants of the same wildflower species together, followed by grass and then another group of wildflowers.

Good grasses include side-oats grama (Bouteloua curtipendula), little bluestem (Schizachyrium scoparium), and prairie dropseed (Sporobolus heterolepis).

How to Nurture Native Plants

Prepare beds for native plants in spring, after hard frosts, and before the summer heat. Early fall is another golden time to plant native seedlings.

You can prepare native plant beds using the same measures for any other crop. If you are planting native seedlings (not mature plants), sheet mulching techniques will help the soil to retain moisture and prevent weeds. Cover the planting area with a few layers of newspaper. Spread on this a layer of mulch—straw (not hay), composted shredded leaves, or 2 inches of shredded hardwood fines (aka shredded hardwood mulch). Spacing the seedlings as needed, push aside the mulch and cut through the newspaper into the soil to plant. Pat the soil and paper around the seedling and return the mulch near to but not touching the stem (touching could cause crown rot).

Water the plants regularly until they become established, and only in extremely dry periods afterward. Learn more about adequately watering your garden in hot weather. Some plants will flower during the first year, but in the second year, your native plant bed will really start buzzing!

Be Kind to Bees

Many of our native bees travel only short distances to find nectar and forage; this makes protecting their habitat in and around the garden substantial. Approximately 70 percent of native bees nest in the ground, a habitat that can be well protected by undisturbed native plantings. Approximately 30 percent of native bees nest in cavities, such as in wood or plant stems. Leaving native plants’ woody stems erect throughout the winter provides a habitat for these cavity-nesting native bees.

Kevin Allison is the urban soil health specialist for the Marion County, Indiana, Soil and Water Conservation District.

Questions about Native Plants?

For more information on local native plant recommendations, contact your county’s Soil and Water Conservation District, USDA-NRCS District Conservationist, or Cooperative Extension office.