Companion Flowers to Grow Among Your Vegetables

A few flowers dotted among the veg do real work, and it costs you next to nothing. The right blooms pull in bees and hoverflies to set your fruit and veg, draw in the predators that eat your pests, and in a couple of cases lure the pests away from your crops entirely. The result is a busier, better-balanced plot — and usually a better harvest.

This is the heart of a wildlife-friendly garden: you are building a food web that works for you, not just a pretty border. But it pays to be honest. Some companion-planting effects are well supported; others are traditional folklore that may or may not help. Below, I have flagged which is which so you know what you are actually buying when you scatter a packet of seed among your beans.

French and African marigolds (Tagetes)

These are the classic veg-plot flower, and for once the reputation is largely earned. French marigolds (Tagetes patula) and the taller African marigolds (Tagetes erecta) are cheerful, long-flowering and brilliant for pollinators through summer.

Their best-evidenced trick is under glass. In a greenhouse or polytunnel, French marigolds grown alongside tomatoes appear to deter whitefly — the scent seems to confuse and repel them. If you grow tomatoes in a greenhouse and battle whitefly every year, a few pots of Tagetes tucked among the plants is a cheap, pleasant thing to try.

Outdoors, marigolds earn their place differently: their open flowers feed hoverflies, whose larvae are voracious aphid-eaters. There is also long-standing interest in Tagetes roots suppressing certain soil nematodes (microscopic root pests), though this is more relevant to commercial growers and specific pest species than to a typical UK veg bed. Treat the nematode angle as a nice-to-have, not the reason you plant them.

Nasturtiums — the blackfly trap crop

Nasturtiums are the workhorse of veg-plot companion planting, and their main job is to be sacrificed. Blackfly (the black bean aphid) often gather thickly on nasturtiums in preference to your crops — so a row of nasturtiums near your beans acts as a trap crop or decoy. The aphids cluster on the flowers, where you can squash them, blast them off with water, or simply remove the worst-affected stems.

This matters most for runner and broad beans, which are a magnet for blackfly in early summer. Pairing nasturtiums with your beans gives the pests somewhere else to go, and concentrates them where they are easy to deal with. For the full picture on tackling the problem, see blackfly on beans.

Nasturtiums do more than martyr themselves, though. Their bright, open flowers are excellent for bees and other pollinators, and the whole plant — leaves, flowers and the peppery seed pods — is edible, so they earn a place in the kitchen too. They will scramble happily along the ground between rows or trail out of a container.

One word of restraint: nasturtiums are vigorous and will smother smaller plants if you let them. Give them room at the edge of a bed rather than in the middle of your salad.

Calendula (pot marigold)

Don't confuse calendula (Calendula officinalis, the pot marigold) with the Tagetes marigolds above — they are different plants. Calendula is one of the best all-round flowers you can grow for beneficial insects, and it is about as easy as gardening gets.

Its flat, open, daisy-like flowers are perfectly shaped for hoverflies, which can reach the nectar with their short mouthparts. That is the payoff: adult hoverflies feed on the flowers, lay their eggs nearby, and their larvae then work through your aphid colonies. A single hoverfly larva can eat hundreds of aphids before it pupates. If you want to understand how this fits the bigger picture, see attracting beneficial insects.

Calendula self-seeds readily, so one packet sown this year often gives you free plants for seasons to come. It flowers for months, the petals are edible, and it slots happily among lettuce and other salads where a bit of aphid control is always welcome.

Borage — bees and a strawberry classic

Borage (Borago officinalis) is a magnet for bees. Its nodding, star-shaped blue flowers produce nectar generously and refill it quickly, so bumblebees and honeybees work it constantly through summer. More bees on your plot means better pollination, and better pollination means more fruit set on your crops.

Borage is the traditional companion for strawberries, and the logic holds up: strawberries need good insect visits to set well-shaped, fully formed fruit, and a few borage plants nearby keep the pollinators coming. It is equally at home near courgettes and squash, which depend heavily on bees to move pollen between their male and female flowers.

It is a big, bristly plant that self-seeds enthusiastically — give it a corner where it can do its thing, and pull up any seedlings that stray where you don't want them. The young leaves and the flowers are edible too, with a mild cucumber flavour.

Poached egg plant and sweet alyssum

If you want to roll out the welcome mat for hoverflies specifically, these two are the specialists.

Poached egg plant (Limnanthes douglasii) is a low, spreading hardy annual with cheerful yellow-and-white flowers that look exactly like a fried egg — hence the name. Hoverflies and bees adore it. Sown along the front of a bed or as edging, it forms a carpet of nectar right where you want the aphid-eaters working. It self-seeds freely and is genuinely one of the best-value plants for a productive plot.

Sweet alyssum (Lobularia maritima) is the other hoverfly magnet — a low, frothy cushion of tiny white or purple flowers with a honey scent. It is brilliant for edging beds and softening the rim of containers, and it flowers for a very long season. Like poached egg plant, its real job is to keep a steady supply of nectar near your crops so that hoverflies stick around and lay eggs in your aphid colonies.

Both are happy in containers, so even a balcony grower can run a hoverfly station alongside their pots of salad and tomatoes.

Phacelia — bees and a green manure in one

Phacelia (Phacelia tanacetifolia) is a bit of an overachiever. Its lavender-blue, slightly ferny flower spikes are among the best bee plants you can sow — covered in bumblebees and honeybees whenever it is in bloom.

Its second job is as a green manure. Sown on a bare patch of ground, it grows fast, covers the soil, smothers weeds and can be dug in or cut down and left as a mulch to feed the soil. So you can use a gap between crops to do two useful things at once: feed the bees now, and feed the soil later. If you garden no-dig, simply cut it down and leave the residue on the surface rather than digging it in.

A practical tip: if you are using phacelia mainly as a green manure, cut it down before it sets seed, or you will find it popping up all over the plot next year. If you are growing it for the bees, let a patch flower fully first.

Weaving flowers into beds and pots without crowding crops

The aim is to thread flowers through your growing space, not let them take it over. A few simple habits keep things productive:

• Use the edges. Front edges of beds, the ends of rows and the corners are perfect for low growers like calendula, poached egg plant and sweet alyssum. They pull in the insects without shading your crops.
• Plant in small clusters, not singles. A clump of three or four flowers is far more visible to a passing bee than one lone bloom. Repeat clumps along a bed rather than dotting flowers randomly.
• Match height to position. Keep tall plants like borage and African marigolds to the back or north side so they don't cast shade over sun-loving crops such as tomatoes and beans.
• Slot flowers into containers. A trailing nasturtium or a cushion of alyssum around the rim of a pot works just as hard as it would in the ground — useful if you are growing food in containers on a patio or balcony.
• Aim for a long season of bloom. Choose a mix that flowers from late spring to autumn so there is always something for the pollinators and predators. A continuous supply is what keeps them living on your plot rather than just passing through.
• Stagger your sowing. Sowing a few flowers every few weeks, like you would successionally sow salad, spreads the flowering and avoids one big flush followed by nothing.

The goal is a plot that is mostly food with flowers woven through it — enough to keep the insects busy, not so much that your veg is fighting for light and root room.

An honest note on the evidence

Companion planting sits on a spectrum from well-supported to pure tradition, and it is worth being clear-eyed about it.

What is genuinely solid: flowers attract pollinators and predatory insects. Open, nectar-rich blooms near your crops will bring in more bees, hoverflies and other beneficials, and that does measurably help fruit set and aphid control. This part is not in doubt, and it is reason enough to grow these flowers.

Reasonably well-supported: the whitefly-deterrent effect of French marigolds under glass, and nasturtiums working as a trap crop for blackfly. These have decent backing and are low-risk to try.

More traditional, and less proven: many of the specific "plant X next to Y to repel pest Z" pairings you will read about. Some may have a small effect; some are folklore that has been repeated so often it sounds like fact. The marigold-nematode story, for instance, is real in certain commercial situations but easily overstated for a home veg bed.

So plant companion flowers with confidence — but plant them mainly for the proven wins (pollinators and predators), and treat the more magical-sounding claims as a bonus rather than a guarantee. None of these flowers will do any harm, all of them feed wildlife, and most are pretty and edible into the bargain. That is a good deal even before you count the pest control.

When you are ready to extend the idea beyond annual companions, build a backbone of longer-lived nectar plants too — the pollinator plants guide covers the perennials and shrubs that keep your plot buzzing year after year, and the wildlife garden hub ties the whole approach together.