Fruit trees need sunshine, nutrients, and, perhaps surprisingly, a support network. We do not mean fruit tree maintenance services, good friends, or therapy, though the former is certainly helpful to a happy orchard! What we mean instead is companion planting—the act of installing different plant species near each other for mutual benefit. The term is often associated with gardening, but is applicable to Sonoma fruit trees, too. By planting the right species, you can improve soil health, suppress weeds, offer weather protection, and enhance fruit production.
Native Companion Plants for Sonoma Orchards
Native plants are defined as those that have been growing in the North Bay prior to European settlement. Having spent thousands of years adapting to our environment, they’re a natural for our varied soil types and microclimates. Once established, they require less water to prosper—an important consideration in our drought-prone region.
Many of Sonoma’s native plants have deep taproots that break up compacted soil and bring important tree nutrients to the surface. Meanwhile, their dense growth suppresses weeds that compete for your tree’s water and nutrients.
By choosing native plants, you’re creating a holistic ecosystem that supports the health of your trees and our environment.
Native Ground Covers
Ground covers do exactly what their name implies. Low growing, they spread across the ground rather than move upward. In doing so, they protect soil from erosion, retain moisture, moderate soil temperature, and prevent weed establishment. The added benefit is that as these plants shed old leaves, the organic matter decomposes and improves soil structure and fertility over time.
- Yerba Buena: Tolerant to sun and partial shade, Yerba Buena is a champion weed suppressor. It can also handle foot traffic, which is helpful when harvesting fruit trees, as all manner of ladders and feet will be traipsing through. From an aesthetic standpoint, this plant remains green all year and produces a pleasing minty scent.
- California Wild Strawberry: The dappled light beneath orchard canopies is ideal for wild strawberries. In turn, they’ll attract bees, birds, and other pollinators while preventing weeds from taking hold. The bonus with this ground cover is that the small berries are edible!
- Blue-Eyed Grass: Despite its name, this native companion is an iris, not a grass. So, you’ll discover delicate purple-blue flowers in spring. They do well in both full sun and partial shade, and don’t grow taller than 12 inches high. Blue-Eyed Grass is dormant in summer, so it does not compete with your trees for water.
Nitrogen-Fixing Plants
Leaves are green and plants and trees grow because of nitrogen. However, most can’t absorb it from the atmosphere—they must get it from the soil. Nitrogen-fixing plants are the outliers. They’re able to grab atmospheric nitrogen and pull it into the soil. This is because a special bacteria lives in their roots and acts as a kind of filter that draws nitrogen from air pockets for the plant. While living, nitrogen fixers keep most of the nitrogen for themselves. However, as they shed leaves or die back, nitrogen enriches the soil for surrounding fruit trees.
- California Lupine: Sun lovers able to thrive in dry conditions, California Lupines are a great match for our orchards. In the spring, their blooms attract bumble bees, and their fallen flowers make nitrogen available to your fruit trees.
- Native California Clovers: White clover is a European import, and its thick, perennial mat spreads aggressively, choking out other plants. Our native California clovers fix nitrogen just as effectively! Bull clover (Trifolium fucatum) and Pinpoint clover (Trifolium gracilentum) are better neighbors for an orchard floor. Instead of taking over, they grow, fix nitrogen, bloom, and die back. This opens up space (and nitrogen-rich soil) for other native blooms, which, in turn, supports a more diverse range of pollinators. While they aren’t generally found in standard hardware store mixes, seeking them out at native plant nurseries is worth the effort.
Pollinator Magnets
There’s no fruit without pollinators, and bees are not the only creatures that flit from flower to flower. Butterflies, moths, and hummingbirds help, too, and they all need continuous nectar sources throughout the growing season. This means it’s a good idea to integrate plants whose blossoms are present before and after your fruit trees bloom.
- California Poppy: Our state flower reseeds readily, blooms from spring through fall, and attracts a wide range of pollinators. They don’t mind drought or need a lot of nutrients, so they are fairly low maintenance. Just remember that California poppies are assertive self-sowers, so plant them where you don’t mind volunteers.
- Seaside Daisy: This perennial delights in full sun and partial shade. Its cheerful lavender-blue flowers are present nearly the whole year, attracting hoverflies, lacewings, and parasitic wasps that act as a natural pest control.
- Coyote Mint: Drought and full sun tolerant, Coyote Mint blooms in late spring and summer. Its aroma is lovely, and its flowers draw bees, butterflies, and predatory wasps.
Companion Planting Considerations
Adding companion plants to your orchard should be done with intention. Avoid introducing problems by following these guidelines:
- Discourage rodents and prevent moisture buildup: Leave a foot or two of clear space around tree trunks that can lead to plant diseases.
- Plant companions at or beyond the drip line: Position them at or beyond the very edges of your tree’s branches (the drip line). That way, as they establish, they won’t contend with your tree’s feeder roots for resources.
- Provide continuous nectar for pollinators: Stagger bloom periods from early spring through late fall to ensure pollinators have nectar sources throughout the season.
Companion Planting Considerations
A spare orchard floor may look clean, but it’s a bit of a desert. Without birds and insects, mitigating pests and our fluctuating temperatures is all up to you, not to mention you may not be getting the most out of your trees. Companion planting doesn’t just benefit you and your fruit trees—it supports your orchard’s entire web of life. Over time, a companion-planted orchard floor requires less intervention and is more productive, beautiful, and resilient.
If you’d like guidance on the right companion plants for your North Bay fruit trees, contact Sonoma Pruner for a consultation.