Five annuals to bring beneficial bugs to your garden
The term “annuals” refers to plants that complete their life cycle in one growing season and do not re-emerge from their root the following year. Sometimes annuals are tropical perennial plants (or native to a hardiness zone far above Lethbridge’s 4b) but many of the best annuals to have as companion plants in your vegetable garden, perennial gardens, or grown in pots on your deck are true annuals and spread by seed. Because of this, it behooves the gardener to be proactive in annual management and either actively remove spent blooms or seed heads or get to know the plant so it can be controlled by aggressive spring weeding. This article will cover five of my favourite, easy-to-grow, non-native annuals for their ability to support biodiversity and beneficial predatory insects: sweet alyssum, bachelors buttons (cornflower), cosmos, borage, and crimson clover.
Sweet Alyssum
A border-sized “insectary” plant, sweet alyssum is a perennial in zones 5-9 and is considered an invasive in warmer climates where it will bloom through the winter. It won’t survive the winter in Lethbridge but it can easily be introduced to your garden by starting it from seed in a sunny window (it has amazingly fast germination) or picked up as an inexpensive four-pack at your local garden centre. Planting alyssum in the borders of your garden will lead to a wide spread of tiny blooms that attracts hoverflies, ladybugs, lacewings, and tiny, parasitic wasps, all of which feed on aphids and other soft-bodied garden pests. Alyssum is also a great annual to add to a new rock garden that hasn’t filled in, as they spread rapidly. Alyssum may self-sow in protected gardens and can be found in white, pink, and pale purple (white is most common).
Bachelors Buttons/Cornflower
One of the most prolific annuals known to the western world, bachelors buttons are invasive weeds in many warm climates. In Lethbridge, they are a consistent, self-sowing annual that can easily take over an area of disturbed soil (like a new perennial installation or a vegetable garden) if left unchecked. They may be quickly recognized from a seedling after a season of growing them, however, and are very easy to pull and chop up for your compost bin before they start blooming. Furthermore, bachelors buttons are an extraordinary pollinator-attractant and you will be awash in bees when you add it to your garden. No need to purchase plants; simply throw seed in the fall or the spring. The plants grow 30-80cm (12-30 inches) tall and will branch to 30cm/12 inch wide in full sun. They also grow in dry shade, but there they will have a slender, delicate growth habit. Flowers in blue, pink, wine, and almost white attract all manner of bees and are very drought-tolerant. Deadheading can be a challenge as the buds are prolific!
Cosmos
Another plant that is easily grown from seed without the need to start indoors and will self-sow until the end of time in a garden space. Cosmos are daisy-like and produce nectar to attract bees, butterflies, and hummingbirds. There are many varieties that grow from 60cm-180cm (2-6 feet!) and come in an array of colours. I love to grow them at the back of my garden as they are tall and graceful in the wind, with long, spreading branches or as a central tall feature in a container. They really start blooming in mid-summer and will carry on through to November if we have a mild fall, giving lots of winter food to local bee populations. These flowers are drought-tolerant and require almost no maintenance beyond deadheading. Easy to pull.
Borage
This plant is one of my very favourites in the garden and an absolute first-choice for many bee species as it is rich in nectar. It is not for the part-time gardener, though, as it is extremely seedy (with convenient pointed-directly-at-the-soil blooms which protects its nectar from getting diluted) and will take over a vegetable garden in one season. If you’re fine with the extra weeding, know that the plant is fully edible (although a little scratchy), the blooms have been used on cakes and frozen in ice cubes for a little bit of farm-to-fork fancy, and it tastes like cucumber-lettuce. Borage will grow to enormous size if single or be a nifty little border plant if crowded. It’s also a great green-mulch/green manure plant before it seeds, so you can leave the weeded plant right there on the soil or add it to your composter to feed your other plants. Again, no need to purchase plants – this one can be direct sown at any time. Borage is a food source for honeybees, bumble bees, native leaf-cutter bees, and a host plant for the migratory Painted Lady Butterfly. It’s also a good deterrent for cabbage moths and a great companion plant for strawberries and tomatoes!
Crimson Clover
My introduction to this little annual clover was as a cover crop plant for my edible garden spaces and I fell in love with its unique, true red flower (in fact, the specific epithet of crimson clover’s botanical name, incarnatum, means “blood red”). The best thing about this clover is that it has the typical, dense root system and nitrogen fixation of other perennial clovers but it is an annual so the root will add nutrients to your soil when it breaks down through the winter. I don’t find it to be particularly seedy and it hasn’t produced a great amount of self-sown plants in my garden. Crimson clover (unlike red clover, which is actually pink) produces nectar and attracts all types of bees into your garden as well as predatory insects like ladybugs. Its best quality, in my opinion, is how unique, delicate, and boldly coloured it is, for a widely-used, agricultural cover crop plant.
