Sweet Peas repay a little planning around what grows beside them. Sweet Peas are a scented climbing annual grown up canes and trellises. They need full sun, soil with a pH of 6.0–7.5, 6–8 inches of space and 60–70 days to reach maturity, so their neighbours need to suit the same bed and the same season. This guide lists the companions for sweet peas from our crop data, how each one is thought to help, and which close relatives to keep apart.
There are 4 companions listed for sweet peas here: Lavender, Marigolds, Garlic and Chives. Companion planting is traditional garden practice rather than proven science, so benefits below are described in those terms — what gardeners have long said and done. Sweet Peas are in the Fabaceae family, need moderate water, and are sown direct where they are to grow; they are hardy, so they cope with cold weather and can go out early in the season. Expect germination in 7–14 days when the soil is warm and moist. Check any pairing first with the companion-planting finder.
Best companion plants for sweet peas
| Companion | Why it is grown with sweet peas |
|---|---|
| Lavender | A scented perennial that draws pollinators and is traditionally said to deter some pests. |
| Marigolds | Grown as a border or dotted through the bed; its roots are traditionally said to discourage some soil pests, and its flowers attract beneficial insects. |
| Garlic | Its strong scent is traditionally said to deter pests, and it fits neatly at the bed edge. |
| Chives | A small, clumping herb for the bed edge; its onion scent is traditionally said to confuse pests. |
Lavender is the first companion to reach for with sweet peas. Its scented flowers draw pollinators through the whole season and it is traditionally said to deter some pests, so it earns its place at the bed edge. It likes the same sunny, well-drained spot and needs little feeding once established.
How companion planting works
Companion planting works through four overlapping mechanisms.
Pest confusion. Many pests find their host plant by scent. Strong-smelling companions such as Lavender, Marigolds, Garlic, Chives are traditionally said to mask that scent, so the pest passes by. It is a delaying effect, not a barrier.
Pollinator and beneficial-insect attraction. Several companions here flower — Lavender, Marigolds — drawing pollinators and beneficial insects in. Let a few flower, and leave some blooms standing rather than deadheading everything.
Nitrogen fixing. Nitrogen fixing does not apply here — none of the listed companions is a legume.
Ground cover and root layers. No companion here is a ground-cover plant, so mulch does that job instead. Deep roots beside shallow ones also compete less for water and nutrients.
None of this replaces the basics. Spacing, watering, rotation and weekly inspection matter more than any pairing.
Plants to avoid near sweet peas
The plants to keep away from sweet peas are its own relatives. Sweet Peas belong to the Fabaceae family, and plants in the same family share the same pests and diseases — here, aphids, bean beetles, slugs and cutworms — so problems pass easily between them and build up in the soil.
| Plant to avoid | Why |
|---|---|
| Green Beans | Same Fabaceae family; shares pests such as aphids, bean beetles, slugs and cutworms. |
| Peas | Same Fabaceae family; shares pests such as aphids, bean beetles, slugs and cutworms. |
| Lima Beans | Same Fabaceae family; shares pests such as aphids, bean beetles, slugs and cutworms. |
| Snap Peas | Same Fabaceae family; shares pests such as aphids, bean beetles, slugs and cutworms. |
| Snow Peas | Same Fabaceae family; shares pests such as aphids, bean beetles, slugs and cutworms. |
Keep these relatives in a different bed and rotate the Fabaceae family to fresh ground each year. If you are unsure whether a plant is a relative, check your local extension service before planting it beside sweet peas.
Planting layout and spacing
One plant needs 6–8 inches and a spot that suits its needs; once it is planted, it stays put, so choose the site carefully.
Give sweet peas their full spacing of 6–8 inches between plants. Crowded sweet peas mean poor airflow, more disease and smaller harvests, and no companion plant compensates for it. Work out how many plants fit your bed with the plant-spacing calculator or the square-foot garden planner.
Plant companions in the spaces the spacing leaves, not instead of it. Low companions go at the foot of the canes, where they shade the soil and keep it moist; taller ones go at the north side so they do not shade the climbers; scented herbs go closest to the stems, dotted along the row.
Sweet Peas are sown direct where they are to grow; they are hardy, so they cope with cold weather and can go out early in the season. Expect germination in 7–14 days when the soil is warm and moist. The watering calculator gives a starting point for your bed size. Expect 60–70 days from sowing to maturity. Work backwards from your last frost date with the seed-starting calculator. If growth is poor despite good care, check your local extension service for advice specific to your area and soil.
Common problems and fixes
The pests most often reported on sweet peas are aphids, bean beetles, slugs and cutworms. Companions may reduce pressure, but they do not prevent them — inspect leaf undersides and new growth weekly and act while numbers are low.
| Problem | What you see | First fix |
|---|---|---|
| Aphids | Sap-sucking insects on new growth; leaves curl. | Wash off with water; encourage ladybirds. |
| Bean beetles | Beetles that chew leaves and pods. | Hand-pick; cover young plants with row cover. |
| Slugs | Chewed leaves and silvery trails, worst in damp weather. | Beer traps or copper tape; clear debris. |
| Cutworms | Caterpillars that fell seedlings by chewing stems at soil level. | Cardboard collar around each young stem. |
Aphids
Wash them off with a strong jet of water and leave ladybirds and lacewings alone to eat them. Check the undersides of young leaves, where colonies start.
Bean beetles
Bean beetles chew holes in leaves and pods. Hand-pick them off young plants and cover new growth with row cover until plants are big enough to cope.
Slugs
Slugs feed at night in damp weather. Clear boards, pots and debris where they hide by day, and set beer traps at soil level near the worst-hit plants.
Cutworms
Push a cardboard collar an inch into the soil around each young stem. Check beds at night with a torch when seedlings start falling.
Unsure what you are seeing? Try the pest-identifier helper or the plant-disease checker. Remove badly affected leaves and rotate the Fabaceae family next year.
Frequently asked questions
What is the best companion plant for sweet peas?
The most widely recommended companions are lavender. A scented perennial that draws pollinators and is traditionally said to deter some pests.
What should not be planted near sweet peas?
Avoid other members of the Fabaceae family, including Green Beans, Peas, Lima Beans, Snap Peas, Snow Peas. They share the same pests and diseases as sweet peas, so problems move easily between them. Rotate the family to a fresh bed each season.
Can I plant sweet peas with marigolds?
Yes. Marigolds is on the companion list for sweet peas. Grown as a border or dotted through the bed; its roots are traditionally said to discourage some soil pests, and its flowers attract beneficial insects.
How far apart should sweet peas and their companions be planted?
Space sweet peas plants 6–8 inches apart, and put companions in the gaps, along the edges and at the ends of rows. The seed-spacing calculator and the plant-spacing calculator work out how many plants fit your bed.
Does companion planting replace pest control?
No. It may reduce pest pressure, but it does not replace inspection, spacing, watering, rotation and good airflow. Check plants weekly and act early, and check your local extension service for advice on pest problems that keep coming back in your area.