Companion Planting Combinations That Actually Work in Kitsap County
If you've ever stood in the seed aisle wondering whether to plant basil next to your tomatoes or dill near your carrots, you've already bumped into the idea of companion planting. The concept is straightforward: some plants help each other grow, while others compete or invite shared pest problems. But finding a garden companion planting chart that actually reflects the conditions, timing, and plant families common to Kitsap County growing is harder than it should be.
This guide is built for Pacific Northwest gardens specifically. Kitsap's cool maritime climate, heavy clay soils, long wet springs, and abbreviated summers change which combinations pay off and which ones don't. At Roots and Wings Gardening, we approach the garden as an ecosystem — not a collection of individual plants — so companion planting isn't a trick we bolt onto a garden plan. It's baked into how we think about spacing, rotation, and plant family relationships from the start.
Below you'll find a working flower companion planting chart, vegetable and herb pairings organized by plant family, and a fruit companion planting chart for the berry crops that do so well across Kitsap, Pierce, and Mason Counties.
Why Companion Planting Works (and When It Doesn't)
Companion planting works through several overlapping mechanisms:
- Pest confusing and masking: Strong-scented plants like alliums and herbs disrupt the chemical signals insects use to find host plants.
- Beneficial insect attraction: Flowers with open, accessible pollen structures bring in predatory and parasitic insects that prey on garden pests.
- Nitrogen fixation: Legumes pull atmospheric nitrogen into root nodules, enriching the soil for neighbors and successors.
- Physical barriers and microclimates: Tall plants can shade and cool soil-sensitive crops. Low groundcovers suppress weeds and retain moisture.
- Root interaction: Some plants exude chemicals through roots that suppress fungal pathogens or nematodes in the surrounding soil.
Companion planting does not replace crop rotation, soil building, or pest management. It supports those practices. If you plant the same plant family in the same bed year after year, no companion plant will save you from the cumulative pest and disease pressure that builds in the soil. Spring soil preparation and thoughtful rotation are the foundation. Companions are one more layer on top.
Companion Planting Organized by Plant Family
At Roots and Wings Gardening, we rotate and manage by botanical family rather than individual plant. That framing matters for companion planting too, because plants in the same family often share the same beneficial companions and the same problematic ones.
Solanaceae — Tomatoes, Peppers, Eggplant, Tomatillos, Potatoes
Solanaceae crops are heavy feeders and among the most pest-prone in any Kitsap garden. They benefit enormously from the right companions.
Best companions:
- Basil: The most well-known tomato companion. Planted at the base of tomato plants, basil is said to improve flavor and repel aphids and thrips. It also attracts pollinators during its flowering stage.
- Borage: Deters tomato hornworm and attracts bumblebees. Borage self-seeds freely — a bonus in Kitsap's long shoulder seasons.
- Marigolds (Tagetes spp.): French marigolds are one of the most researched companion plants in the world. Their root exudates suppress soil nematodes, and their strong scent confuses whiteflies and aphids. Plant them as a border or interplanted densely.
- Carrots: Loosen the soil around tomato roots when interplanted early, though mature carrots may become stunted by tomato root competition. Plant carrots while tomatoes are still small.
- Alliums (garlic, onions, chives): Planted around tomatoes and peppers, alliums deter aphids and spider mites. Chives in flower attract beneficial insects.
Avoid planting Solanaceae near:
- Fennel: Fennel is allelopathic — it produces chemicals that stunt the growth of many garden plants, including tomatoes. Keep fennel in its own isolated bed or container.
- Brassicas: These are heavy feeders competing for the same nutrients without offering anything back. They also share some fungal vulnerabilities under wet Pacific Northwest conditions.
- Other Solanaceae: Never follow potatoes with tomatoes — they share late blight (Phytophthora infestans), which persists in Kitsap's wet soil.
For more on growing Solanaceae crops in Kitsap's challenging short-season climate, see our guides to growing tomatoes, growing peppers, and growing potatoes in the Pacific Northwest.
Brassicaceae — Broccoli, Cabbage, Kale, Cauliflower, Brussels Sprouts, Kohlrabi, Arugula, Radishes, Turnips
Brassicas are arguably the most pest-targeted plant family in any Pacific Northwest food garden. Cabbage moths, cabbage loopers, aphids, flea beetles, and slugs all love them. Companion planting is a real tool here.
Best companions:
- Nasturtiums: Nasturtiums are a classic trap crop for aphids. Aphids are strongly attracted to nasturtiums and will colonize them preferentially, drawing pressure away from your brassicas. Once aphid colonies establish on the nasturtiums, beneficial insects follow and the balance often self-corrects.
- Dill: Flowering dill is one of the best plants in any garden for attracting parasitic wasps that lay eggs in caterpillar pests — including imported cabbageworm. Plant dill around the perimeter of your brassica bed and let it flower.
- Marigolds: As with Solanaceae, marigolds' strong scent helps mask brassicas from egg-laying moths and butterflies.
- Alliums: Onions, garlic, and chives planted around brassicas deter cabbage moths and aphids. Onions are especially useful at bed edges.
- Celery: Interplanted with cabbage, celery is said to repel the white cabbage moth. Celery also benefits from the partial shade larger brassicas provide.
- Chamomile: A gentle neighbor that attracts beneficial insects and is said to improve the vigor of brassicas planted near it in small quantities.
Avoid planting Brassicaceae near:
- Strawberries: Brassicas and strawberries are poor neighbors — they compete aggressively for soil nutrients and can suppress each other.
- Tomatoes and peppers: See Solanaceae section above.
- Fennel: Keep fennel away from all brassicas.
Kitsap gardeners growing brassicas should also read our individual crop guides for broccoli, cabbage, kale, cauliflower, Brussels sprouts, kohlrabi, arugula, and turnips.
Alliaceae — Garlic, Onions, Leeks, Shallots, Chives, Scallions
Alliums are companion plants as much as they are crops. Their sulfur compounds act as broad-spectrum pest deterrents, and their flowers — especially chives — are outstanding for attracting beneficial insects.
Best companions for alliums:
- Carrots: One of the most reliable pairings in any garden companion planting chart. Carrot fly is deterred by onion scent; onion fly is deterred by carrot scent. They mask each other's chemical signature effectively. Alternate rows when space allows.
- Roses and fruit trees: Garlic and chives planted around the base of roses significantly reduce black spot and aphid pressure. The same principle applies to fruit trees — alliums under apple, pear, and plum trees help suppress soil fungal issues.
- Brassicas: As discussed above, alliums are among the best companions for the entire Brassicaceae family.
- Tomatoes and peppers: Alliums deter aphids and spider mites around Solanaceae crops.
Avoid planting alliums near:
- Beans and peas: This is one of the most well-documented incompatibilities in any companion planting chart. Alliums suppress the growth of legumes — possibly by inhibiting the Rhizobium bacteria that legumes depend on for nitrogen fixation. Keep them separated by at least a full bed.
- Other alliums in high density: Planting large allium crops together increases the risk of white rot, a serious soil-borne fungal disease that persists for decades.
For full growing details, see our guides on growing garlic, growing onions, and growing leeks in Kitsap County.
Cucurbitaceae — Cucumbers, Zucchini, Summer and Winter Squash, Melons, Pumpkins
Cucurbits need strong pollinator activity to set fruit — this is the family where a thoughtful flower companion planting chart pays the biggest dividends. Kitsap's wet cool springs often suppress bee activity exactly when cucurbit flowers are opening, making pollinator-attracting companions especially important here.
Best companions:
- Nasturtiums: A top companion for all cucurbits. Nasturtiums attract aphids away from squash and cucumbers (trap crop function), attract pollinators with their bright flowers, and their sprawling habit helps suppress weeds around cucurbit base stems. Both flowers and leaves are edible.
- Marigolds: Deter cucumber beetles and squash bugs. Plant densely around the perimeter of cucurbit beds.
- Borage: Attracts bumblebees aggressively — bumblebees are the most effective pollinators for squash and zucchini flowers. Borage planted at the corners of a squash bed measurably improves fruit set in cool-weather gardens.
- Beans: The Three Sisters planting — corn, beans, and squash — is one of the oldest recorded companion planting systems in the Americas. Beans fix nitrogen that corn and squash consume. Squash leaves shade the soil, retaining moisture and suppressing weeds. In Kitsap, this system works well in warm, sheltered spots with amended soil.
- Dill and parsley: Attract parasitic wasps and predatory beetles that prey on cucumber beetles and aphids.
Avoid planting Cucurbitaceae near:
- Potatoes: Both attract similar soil pests and compete for nutrients without mutual benefit.
- Aromatic herbs in large quantities: Strong-scented herbs planted too densely near cucurbits can repel pollinators as well as pests — balance matters.
For more on growing these crops locally, see our guides to cucumbers, zucchini, and squash varieties worth growing in Kitsap County.
Apiaceae — Carrots, Parsnips, Parsley, Cilantro, Dill, Fennel, Celery, Celeriac
The Apiaceae family produces some of the most powerful beneficial-insect-attracting flowers in the garden — small, flat-topped umbels that are structurally perfect for parasitic wasps, hoverflies, and ground beetles. Letting members of this family flower intentionally is one of the highest-leverage things a Kitsap gardener can do for natural pest control.
Best companions:
- Alliums + carrots: As noted above, this is the gold standard pairing for mutual pest deterrence.
- Roses and fruit trees + Apiaceae flowers: Letting parsley, cilantro, and dill flower near fruiting plants brings in predatory insects that dramatically reduce aphid and caterpillar pressure.
- Brassicas + dill: Dill in flower near brassicas is one of the most effective ways to introduce parasitic wasp populations that target cabbageworm and looper caterpillars.
- Tomatoes + parsley: Parsley interplanted with tomatoes attracts hoverflies, whose larvae are voracious aphid predators.
The fennel exception: Fennel (Foeniculum vulgare) is in the Apiaceae family but behaves as an allelopathic loner. Its root exudates inhibit germination and growth in most neighboring plants, including tomatoes, peppers, beans, and brassicas. Grow fennel in an isolated bed or container. The flowers still attract beneficial insects, so you don't have to sacrifice that benefit — just keep the roots separate.
Avoid planting Apiaceae near:
- Fennel near anything: Already addressed — isolate it.
- Dill near carrots at maturity: Dill and carrots can cross-pollinate if both are allowed to go to seed simultaneously. Fine for annual harvest, but keep in mind if you're saving carrot seed.
See our individual guides for carrots, parsnips, celery, and fennel for crop-specific growing details.
Fabaceae — Beans, Peas, Favas, Lentils, Edamame, Cover Crop Legumes
Legumes are the nitrogen engine of any food garden. Their companion value extends beyond what grows next to them in a single season — they improve soil for whatever follows them in rotation.
Best companions:
- Corn: Classic Three Sisters pairing. Beans climb corn stalks and fix nitrogen that corn demands in enormous quantities. Corn in Kitsap benefits significantly from interplanted beans in warm, sheltered locations.
- Squash: The third sister. Squash shades bean and corn root zones, retaining moisture and suppressing weeds.
- Carrots: Beans and carrots are excellent neighbors. Beans provide light nitrogen enrichment; carrots loosen soil around bean roots without competing aggressively for nutrients.
- Marigolds: Planted around bean beds, marigolds deter Mexican bean beetles and nematodes that can damage Fabaceae root systems.
- Potatoes: Beans and potatoes have a mutually beneficial relationship — beans repel the Colorado potato beetle, and potatoes can slightly shelter young bean seedlings from late spring wind and rain, which is common in Kitsap.
Avoid planting Fabaceae near:
- Alliums: As noted — onions, garlic, leeks, and chives inhibit legume growth. Keep these families separated.
- Fennel: Allelopathic effects inhibit bean germination and early growth.
See our complete growing guides for beans and peas in Kitsap County.
Flower Companion Planting Chart for Kitsap County Gardens
Flowers aren't decorations added to a food garden. In a well-designed garden, they're functional infrastructure — attracting beneficials, deterring pests, supporting pollinators, and improving the soil. Here is a working flower companion planting chart for Pacific Northwest growing conditions:
| Flower | Best Planted Near | Primary Function | Kitsap Notes |
|---|---|---|---|
| French Marigold (Tagetes patula) | Tomatoes, peppers, beans, cucurbits, brassicas | Nematode suppression, whitefly and aphid deterrence, pollinator attraction | Start indoors in March for transplanting after last frost. Performs well through Kitsap's cool summer nights. |
| Nasturtium (Tropaeolum majus) | Cucurbits, brassicas, beans, fruit trees | Aphid trap crop, pollinator attraction, ground cover, edible | Direct sow after last frost. Self-seeds readily in Kitsap. Can become aggressive in rich soil — plant in slightly lean beds. |
| Borage (Borago officinalis) | Tomatoes, squash, strawberries | Bumblebee attraction, hornworm deterrence, calcium accumulation in soil | Thrives in Kitsap's mild, moist climate. Self-seeds aggressively — plan accordingly. Flowers are edible and beautiful. |
| Phacelia (Phacelia tanacetifolia) | Any bed needing beneficial insect support | Outstanding for attracting hoverflies and parasitic wasps; also used as a green manure cover crop | Underused in home gardens. Grows quickly in cool temperatures — ideal for Kitsap. Direct sow in early spring or fall. |
| Calendula (Calendula officinalis) | Tomatoes, brassicas, asparagus | Attracts hoverflies; sticky stems trap aphids and whiteflies; anti-fungal root exudates | Thrives in cool weather — one of the longest-blooming annuals in Kitsap. Direct sow in March or April for early season coverage. |
| Sweet Alyssum (Lobularia maritima) | Brassicas, lettuce, strawberries | Ground-level hoverfly and parasitic wasp habitat; low-growing weed suppression; continuous bloom | Excellent edging plant for Kitsap vegetable beds. Performs well in cool, moist conditions and self-seeds reliably. |
| Chives in flower (Allium schoenoprasum) | Carrots, tomatoes, roses, fruit trees, brassicas | Aphid and spider mite deterrence; pollinator attraction during bloom; fungal suppression near roses | One of the most versatile perennial companions in any Kitsap food garden. Plant once and divide annually. |
| Lavender (Lavandula angustifolia) | Brassicas, fruit trees, berry patches | Strong pollinator magnet; deters moths and flies from laying eggs on neighboring plants | Grows well in Kitsap's well-drained spots. Avoid planting in heavy clay without amendment. Long-lived once established. |
| Sunflowers (Helianthus annuus) | Cucurbits, corn, beans | Aphid habitat (trap crop for aphid colonies that attract lacewings and ladybugs); pollinator beacon; windbreak for sheltered beds | Useful as a north-side windbreak in Kitsap's exposed sites. Allow aphid colonies on sunflowers early in season — beneficials follow. |
Fruit Companion Planting Chart for Kitsap County
Kitsap County is exceptional berry-growing territory. Strawberries, raspberries, and blueberries thrive here, and the right companions amplify their productivity significantly. This fruit companion planting chart focuses on the small fruits most commonly grown in home gardens across the region.
| Fruit Crop | Best Companions | Why It Works | What to Avoid |
|---|---|---|---|
| Strawberries | Borage, thyme, sage, spinach, lettuce, chives, garlic | Borage improves flavor and deters pests. Thyme and sage deter slugs — a major Kitsap pressure. Alliums reduce aphid and grey mold pressure. Low-growing greens fill gaps between runners without competing heavily. | Brassicas (compete aggressively); fennel; any other Solanaceae |
| Raspberries | Chives, garlic, tansy, marigolds, yarrow | Garlic and chives at the base of raspberry canes reduce aphid pressure and suppress soil fungal issues. Yarrow attracts parasitic wasps. Tansy deters raspberry beetles. Marigolds as a border suppress nematodes in the root zone. | Potatoes and tomatoes (share verticillium wilt); blackberries (compete and can introduce disease) |
| Blueberries | Rhododendrons (shared acid soil affinity), thyme, oregano, clover as groundcover, chives | Blueberries need highly acidic soil (pH 4.5–5.5) that limits their companion options — most vegetables won't thrive in these conditions. Thyme and oregano tolerate acid soil and deter pests. Low clover groundcover fixes nitrogen at low levels and keeps weeds down. Chives repel aphids without changing soil pH significantly. | Most vegetables (wrong pH); fennel; shallow-rooted annuals that disturb the blueberry's fibrous root system |
  "Holly completely transformed our estate! From planning raised beds to planting a variety of vegetables, she made everything so simple and approachable. Not only do we have a thriving garden now, but she taught us how to care for it ourselves. Her passion and knowledge are unmatched - I can’t recommend her enough!"Lori H. Private Gardening Client |