Catnip repay a little planning around what grows beside them. Catnip are a mint relative with grey-green leaves that cats find irresistible, grown for cat toys and teas, and a tough, drought-tolerant plant for a sunny corner. They need full sun, soil with a pH of 6.0–7.0, 12–18 inches of space and 70–90 days to reach maturity, so their neighbours need to suit the same bed and the same season. This guide lists the companions for catnip from our crop data, how each one is thought to help, and which close relatives to keep apart.
There are 4 companions listed for catnip here: Tomatoes, Peppers, Marigolds and Cabbage. 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. Catnip are in the Lamiaceae family, need low water, and are started indoors or sown direct; they are hardy and tolerate cold, so they can go out early in the season. Check any pairing first with the companion-planting finder.
Best companion plants for catnip
| Companion | Why it is grown with catnip |
|---|---|
| Tomatoes | A tall, sun-loving neighbour for the same warm bed; plant the herb at the sunny edge so it is not shaded out, and keep spacing generous for airflow. |
| Peppers | Another heat-lover for the same sunny bed; its upright habit leaves room at its feet for low herbs. |
| 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. |
| Cabbage | Catnip's strong scent is traditionally said to help mask cabbage from pests; grow it in a pot, as it spreads. |
Tomatoes are the first companion to reach for with catnip, and it is vigorous and can spread, so it is best given its own patch at the edge of a bed rather than the middle of it. It is the tall neighbour that sets the shape of the bed: stake it well, keep the lower leaves clear, and plant the herb at its sunny base where it gets light without being shaded out.
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 aromatic herbs 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 — Marigolds — drawing pollinators and beneficial insects in. Let a few flower.
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 catnip
The plants to keep away from catnip are its own relatives. Catnip belong to the Lamiaceae family, and plants in the same family share the same pests and diseases — here, aphids, spider mites, whiteflies — so problems pass easily between them and build up in the soil.
| Plant to avoid | Why |
|---|---|
| Basil | Same Lamiaceae family; shares pests such as aphids, spider mites, whiteflies. |
| Mint | Same Lamiaceae family; shares pests such as aphids, spider mites, whiteflies. |
| Rosemary | Same Lamiaceae family; shares pests such as aphids, spider mites, whiteflies. |
| Thyme | Same Lamiaceae family; shares pests such as aphids, spider mites, whiteflies. |
| Oregano | Same Lamiaceae family; shares pests such as aphids, spider mites, whiteflies. |
Keep these relatives in a different bed and rotate the Lamiaceae family to fresh ground each year. Others in the same family in our crop data include Sage, Lavender, Marjoram.
Planting layout and spacing
Space 12–18 inches apart and consider a pot or a contained spot — catnip spreads like its mint cousins.
Give catnip their full spacing of 12–18 inches between plants. Crowded catnip 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 in the gaps and along the bed edges; taller ones go at the north side so they do not shade the catnip; scented herbs go closest to the crop, dotted through the row.
Catnip are started indoors or sown direct: sow under cover where needed, expect germination in 7–14 days, and set plants out once the weather is right. Work backwards from your last frost date with the seed-starting calculator. Catnip need full sun and soil with a pH of 6.0–7.0. Water needs are low, so water sparingly once established and never let the soil stay wet — most failures come from too much water, not too little. The watering calculator gives a starting point for your bed size. Expect 70–90 days from sowing to maturity.
Common problems and fixes
The pests most often reported on catnip are aphids, spider mites, whiteflies. 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. |
| Spider Mites | Fine webbing and speckled, bronzed leaves in hot, dry weather. | Spray leaf undersides with water; raise humidity. |
| Whiteflies | Tiny white insects that rise in a cloud when disturbed. | Yellow sticky traps; wash leaf undersides. |
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.
Spider Mites
Spider mites thrive in hot, dry conditions. Spray leaf undersides with water regularly and avoid dusty, drought-stressed plants, which are hit hardest.
Whiteflies
Put out yellow sticky traps to monitor numbers and wash leaf undersides with water. They breed fastest in warm, still air, so keep airflow good.
Unsure what you are seeing? Try the pest-identifier helper or the plant-disease checker. Remove badly affected leaves and rotate the Lamiaceae family next year.
Frequently asked questions
What is the best companion plant for catnip?
The most widely recommended companions are tomatoes. A tall, sun-loving neighbour for the same warm bed; plant the herb at the sunny edge so it is not shaded out, and keep spacing generous for airflow.
What should not be planted near catnip?
Avoid other members of the Lamiaceae family, including Basil, Mint, Rosemary, Thyme. They share the same pests and diseases as catnip, so problems move easily between them. Rotate the family to a fresh bed each season.
Can I plant catnip with peppers?
Yes. Peppers are on the companion list for catnip. Another heat-lover for the same sunny bed; its upright habit leaves room at its feet for low herbs.
How far apart should catnip and their companions be planted?
Space catnip plants 12–18 inches apart, and put companions in the gaps, along the edges and at the ends of rows. The plant-spacing calculator works 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.