Good companions love to be together. In the plant world a good companion can be worth it’s weight in gold. Companion plants usually provide some kind of service to another plant. The good companion will play one or more roles – attractors, deterrents, repellants, sun shades, supports, space sharers and weed suppressors. Pop your tomatoes in pots near your asparagus bed to help the roots of the tomatoes stay uninfected from nematodes.
An armoury of looks, smells and tastes to keep the undesirable away or attract the right types. The companion’s shape or size may be helpful to others. Different root systems will also create a much better soil structure over time. Some roots grow deep and other spread widely so putting them together brings a harmony.
Many vegetables love a good companion to stop them being infested by pests. This could be other vegetables, herbs or flowering plants. This is a time for seed planting in the greenhouse or direct, so it is worth grabbing a few of the companions from your favourite seed provider to put in at the same time.
Some good companions can have dual use. Borage’s blue flowers attract bees, butterflies and hoverflies. Amazingly they refill with nectar within two minutes of being visited by a bee! Planted around the plot they’ll encourage these pollinators in. It may improve the taste of strawberries if planted nearby. They’ll look pretty floating on a drink later in the year too. However they are not good companions for cats, dogs and horses.
Social Climbers
Sweetcorn can provide shade for other crops below it. Planting sweet corn in a grid makes a shady space to grow crops that don’t want to be scorched. Lettuce will enjoy being underneath and can cope with the sweet corns tendril like root structure. Sweetcorn will also provide support to crops that may need a trellis or other support.
Beans, peas, cucumbers and squashes grown near the corn will gradually creep up them. Beans will also pull nitrogen from the air to benefit the sweetcorn’s roots. Squashes like the dappled shade provided by the corn and will suppress weeds as they spread. Their leaves will keep the ground cooler and conserve water too.
A couple of you scratch my back I’ll scratch yours pairing! If you prefer you good companion to be a bit more flamboyant choose a flower that likes to grow upwards like a sweet pea. Easy to walk among the rows to pick them.
Fragrant and Flowery Friends
Strongly scented plants make good companions as they confuse pests. A number of herbs can also be used for their scent to ward off insects. Rosemary, sage, dill and mint work well around the cabbage family. Mint needs to be contained though otherwise it will smother. Herbs are great insect repellants for plants and humans. A bunch of basil in a glass jar on a table outside in summer will keep the mozzies at bay.
French marigolds look lovely and have a strong slightly acrid smell. This odour is not liked by greenfly or blackfly so will keep them clear of anywhere you plant them. If you prefer something to eat yourself then chives can do the same job alongside carrots. Nip off the flower heads as they die as they will self-seed all easily if left to blow in the wind.
Nasturtiums are a glorious blaze of colour in any garden or plot. They will creep and climb or trail. Best of all they will attract cabbage white butterflies away from the summer brassicas where they like to lay their eggs. They will also keep squash vine borers at bay. The bright yellow of calendulas attract helpful insects. Ladybirds adore them as do lace wings. The larvae of those insects get rid of aphids. Another dynamic duo is putting carrots with leeks. The leek repels carrot fly. It’s sweet orange friend repels only fly and leek moth. They need to be planted at the same time though.
Fatal Attraction
So when do plants not make good companions? Well when they need similar nutrients, water and space either above the ground or below. Sunlight lovers should be given space. Tomatoes and potatoes can both suffer from blight which is not good to share. Keep them all separated from other crops. Fennel is another plant that benefits from a bit of solitude. Carrots and parsnip can both be attacked by carrot fly and share the same soil-borne diseases, so putting them together increases risk of losing not one but two crops. Cucumbers suffer if planted next to strong herbs such as sage. The water content in the cucumber sucks in the flavour and can get bitter. So it is worth getting to know who is who and what is what with the plants to ensure good neighbours.