Geraniums repay a little planning around what grows beside them. Geraniums are a tender perennial flower grown in beds and pots. 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 geraniums from our crop data, how each one is thought to help, and which close relatives to keep apart.
There are 4 companions listed for geraniums 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. Geraniums are in the Geraniaceae family, need moderate water, and are started indoors and transplanted out once the weather warms; they are tender, so frost will kill them and they should only go outside once all danger of frost has passed. 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 geraniums
| Companion | Why it is grown with geraniums |
|---|---|
| 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 geraniums. 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 geraniums
No other crop in our data belongs to the Geraniaceae family, so there is no same-family crop in our data to list as a plant to avoid near geraniums. That does not mean anything goes: the rule still applies. Do not plant geraniums where another Geraniaceae family member grew last year, and rotate the Geraniaceae family to fresh ground each year so pests and diseases do not build up in the soil.
| Plant to avoid | Why |
|---|---|
| Any other Geraniaceae family member | Same family; shares pests such as aphids, slugs and cutworms. |
If you are unsure whether a plant belongs to the Geraniaceae family, check your local extension service before planting it beside geraniums.
Planting layout and spacing
One plant needs 12–18 inches and a spot that suits its needs; in cold zones it is grown as an annual and lifted or replaced each year.
Give geraniums their full spacing of 12–18 inches between plants. Crowded geraniums 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 geraniums; scented herbs go closest to the crop, dotted through the row.
Geraniums are started indoors and transplanted out once the weather warms; they are tender, so frost will kill them and they should only go outside once all danger of frost has passed. 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 70–90 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 geraniums are aphids, 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. |
| 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.
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 Geraniaceae family next year.
Frequently asked questions
What is the best companion plant for geraniums?
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 geraniums?
There is no same-family crop in our data to name for geraniums — no other crop in our data belongs to the Geraniaceae family. The general rule still stands: do not plant geraniums where another Geraniaceae family member grew last year, and rotate the family to fresh ground each season.
Can I plant geraniums with marigolds?
Yes. Marigolds is on the companion list for geraniums. 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 geraniums and their companions be planted?
Space geraniums plants 12–18 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.