Susie’s Garden
Not just a pretty face – our expert looks at marigolds and other companion plants that can drive away insect pests
Each year Fleuroselect, an international organisation for ornamental plants, chooses a flower to represent that year. We are currently in the Year of the Marigold so I thought that this week I would celebrate these useful and colourful plants.
There are two types: African marigolds, the kind often used as edging in front gardens, and Pot marigolds, the cottage garden favourites. Both come in shades of brilliant orange and vivid yellow.
Easy to grow annuals that relish sunshine, they are also helpful in preventing pests and benefiting neighbouring plants. It’s called companion planting, combining plants so that they help each other. Pot marigolds, or calendulas, can be grown among tomatoes to repel whitefly or, as we do here, around the veg garden to attract beneficial insects such as ladybirds, lacewings and hoverflies which will then eat your aphids.
French marigolds, or tagetes, can also be grown among tomatoes. They have a strong smell that repels greenfly and blackfly.
Then there are nasturtiums which you can grow among French and runner beans to lure aphids away, fennel allowed to grow tall and flower to attract hoverflies, and thyme to grow beneath roses.
A lot of the success of companion plants is down to scent driving away pests, so sage can be paired up with carrots or cabbages, garlic planted among roses (garlic
flowers are pretty!) or leeks and carrots grown together.
Some plants affect others in more subtle ways. Yarrow increases vigour in its neighbours and accumulates minerals such as phosphorous, calcium and silica. It’s a useful plant to add to the compost heap.
Plants in the pea family such as lupins and sweet peas draw nitrogen out of the air to store in their roots, which benefits the soil. And in case you think it’s all good, another reason to get rid of invasive couch grass is that it sends out a chemical that slows down growth of other plants.
So, consider how you put plants together, not just for their aesthetic value but for helping you to grow without any need for chemicals.