I’ve always designed and grown gardens with the aim of creating balanced ecosystems, and using companion plants is a big part of it. Companion plants are plants that are grown because they increase your yields: they benefit your crops in different ways, which I have separated in four categories:
Attracts pollinators
Sacrificial plants
Attracts pests’ predators
Deters pests
I’ve listed my 10 go to companion flowers below. Of course, there are many more, this is the easiest to grow and the ones that are specifically known for being great companion plants. When looking for the plants listed below, use the botanical name to ensure you get the right variety.
1. Tagetes patula - French Marigold
Deters pests and attract pests predators
What: Annual flower originating from Mexico, flowering from June to October
Why: French Marigold roots exude a component that kills root feeding nematodes.They also attract hoverflies whose eggs hatch in larvae that feed on aphids (black and green flies)
Where: Excellent companion plant to tomatoes, can also be planted next to all beans as it attracts aphid predators.
2. Tropaeolum - Nasturtium
Sacrificial plant (and delicious to eat too!)
What: Annual in the UK, these species come from central and South America.
Why: Nasturtium are grown as a sacrifice plant to attract blackfly (aphids) away from crops.
They are meant to improve tomato taste, but I haven’t noticed anything myself. Do try and tell me what you think! They are TASTY: all parts of the plant (except the root) are edible: flowers are great on toast or in salads, leaves make a tasty and spicy pesto, and picked buds are like capers, but spicier. They also come in a variety of colours and types (smaller more compact ones work well in pots, rambling ones are great under trees in orchard etc.). They are a real favourite of mine.
Where: Excellent anywhere aphid tends to develop (under fruit trees, near beans, etc.)
Try eating a nasturtium flower differently: eat the pointy back of the flower first (it’s where the nectar is and it is sweet and flowery), then eat the rest of the flower (quite peppery).
3. Origanum majorana- Marjoram
Attracts pollinators, delicious on pizzas
What: Marjoram is a perennial herb originating from the Mediterranean with sweet pine and citrus flavors.
Why: Marjoram will flower freely the whole summer and its flowers are very attractive to pollinators. You will find an array of honey bees, bumble bees, hoverflies and solitary bees on marjoram flowers between spring and autumn.
Where: anywhere in your garden! propagation by either seeds or semi-hardwood cuttings. You can find marjoram plants with flowers in an array of colour: from white to dark pink. Once the flowers are passed their best you can cut the stem back quite low, which will promote more growth and more flowers.
4. Calendula officinalis - Pot Marigold
Attract pests predators
What: An annual flower with richly coloured daisy like flowers in a variety of orange tones. Well, I say annual but often in warmer parts of the UK calendula will survive mild winter and flower most of the year. You really can’t go wrong with tem!
Why: The strong colour of calendulas attracts hoverflies, lacewings and ladybirds. The insect females feed on the calendulas’ protein-rich pollen before laying eggs on colonies of aphids, which provide a ready food source when the larvae hatch.
Where: Plant anywhere in your garden, and you can save the seeds easily. Once the flower heads are dry, gently pull them out and sow liberally wherever you want more flowers, or keep in a jar or paper bag to share with neighbours or for next year.
5. Allium Tuberosum - Garlic Chives
Deters pests and lovely to eat.
What: Garlic chives is a plant from the onion family with edible leaves and umbels of small, fragrant, star-shaped white flowers. It originates from china, and grows very well in the UK.
Why: Garlic chives strong scent confuses and deters the carrot root fly, which can normally smell carrots from up to a mile away.
Where: plant alongside carrots (it’s a hardy perennial plant). Garlic chives are also great in any herb garden as they make a tasty addition to salads and other dishes.
6. Mentha spicata- spearmint
Deters pest and attract pests predators
What: spearmint is a non evergreen perennial plant. It will survive for years, and the leaves die off in winter before growing back in the spring.
Why: pulgone is found in mint oil and can be effective at confusing pests of carrots, tomatoes, alliums and brassicas. It can also deter flea beetles. Spearmint lovely purple flower will also attract pollinators and pests predators like hoverflies, predatory wasps and ladybirds.
Where: DO NOT PLANT MINT STRAIGHT IN THE GROUND as it will take over and will be very difficult to manage once it has spread. Instead, use pots and move them around your garden.
7. Erysimum - Bowles’s Mauve wallflower
Attracts pollinator and sacrificial plant
What: A purple wallflower from the Brassicaceae family, can be annual biennial or perennial.
Why: It has a very long flowering season and encourages beneficial insects, such as ladybirds, lacewings and hoverflies into the garden. Aphids and cabbage whiteflies tend to prefer it to other cabbages.
Where: as a companion to all cabbages as common cabbage pests tend to go to wallflowers first. Don’t forget to take the plant out and put it in the bin once it is infested.
8. Agastache foeniculum - Anise Hyssop
Attracts pollinators and is very tasty!
What: Anise Hyssop is a species of perennial plant in the mint family. It is semi native (it originates from the northern hemisphere, but a different continent - North America). It has gorgeous spikes of purple flowers that will fit right in a traditional cottage herbaceous border.
Why: Its purple flowers attract a range of butterflies, bumblebees, honey bees, carpenter bees, and night flying moths. Most pollinators see colours differently top us, and anise hyssop is really visible in pollinators radar.
Where: anywhere in your garden where you have space and don’t intend to plant something else in the future. It can get quite big, and has really stunning flowers. Also, its leaves are edible and deliciously anise- like. Great to make syrup, teas or to infuse water.
9. Lavandula angustifolia - English lavender
Attracts pollinators
What: English lavender is a hardy evergreen medium size shrub that thrives in full sun. It has narrow leaves and spikes of flowers that came in different tones of purple and pink. It is beautifully scented and the dried flowers are used in a variety of ways from cooking to medicine.
Why: Lavender’s purple flowers are very attractive to bees and all pollinators alike. Lavender bushes have a lot of flowers at once, which is very useful to pollinators as they don’t have to travel far to get a lot of pollen and nectar in one go.
Where: lavender are sun loving hardy perennial, so plant them in the sunniest and driest part of your garden, using poor soil. They don’t like rich soil, so don’t waste good compost on your lavender plants. Give them a good pri=unte in the autumn to keep them going, and if you prune the flower spikes down after the first flowering, you can get a second flush of flowers. For maximum effect, plant lavender bushes in clumps, or along a garden path.
10. Nepeta mussini - Catmint (not catnip)
Attracts pollinators and cats (hear me out!)
What: Catmint is a perennial bush from the nepeta family and has spear shaped leaves with flushes of purple, lilac or white flowers from spring to autumn. They like the sun and tolerate dry conditions once established. Deer and rabbits will leave Catmint alone.
Why: The purple flowers coupled with the long flowering season makes catmint really attractive to pollinators. Catmint contains nepetalactone which binds to the olfactory receptors of cats, typically resulting in temporary euphoria (not dangerous to cat, and really funny to watch for humans).
Where: If you have issues with cats in your garden, plant Catmint away from where you DON’T want cats to lure them in another spot.
Remember that a healthy garden is a garden with a variety of plants and habitats. Happy growing!