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Bee-friendly plants put to the test



Are our favourite garden flowers attractive to hungry visitors such as bees and butterflies?

Gardeners and land managers are increasingly looking for ways to help bees and other pollinators by providing attractive flowers for them to feed on. To do this, they often rely on “pollinator-friendly” plant lists. But these lists are generally based on opinion and experience rather than scientific research.

Now researchers at the University’s Laboratory of Apiculture and Social Insects (LASI) have completed one of the first scientific studies to put the business of recommending pollinator-friendly garden flowers on a firmer scientific footing.

close up of two bees feeding

The study’s findings were recently published in the journal Functional Ecology.

The study, led by PhD student Mihail Garbuzov and Prof. Francis Ratnieks and funded by the Body Shop Foundation, involved repeatedly counting flower-visiting insects over two summers as they foraged on 32 popular summer-flowering garden plant varieties in a specially planted experimental garden on campus, with two smaller additional gardens set up in year two to check the generality of the results.

All the plants studied were popular garden plants, widely and easily available for purchase in nuseries and garden centres, and had to flower mainly or exclusively in July/August.

Bees (87 per cent) and hoverflies (nine per cent) were the most frequent visitors, with butterflies and moths just two per cent and all other insects also two per cent. The researchers observed clear differences in the mix of bee and insect types attracted by different varieties.

Honey bee on borage

Some cultivated varieties and non-native flowers – usually seen as ornamental only – can be helpful to wildlife. For example, open dahlias attracted many bees, especially bumblebees, but pom-pom or cactus dahlias attracted few insects, because their highly bred flowers make it difficult for insects to reach the flowers’ pollen and nectar.

Highly bred varieties of lavender, including those of novel colours, such as white or pink, or hybrid lavenders, proved highly attractive to insects. Plants that the researchers can recommend to gardeners include lavender, marjoram, open-flowered dahlias, borage, and Bowles Mauve Everlasting Wallflower.

Marjoram was probably the best all-rounder, attracting honey bees, bumble bees, other bees, hover flies, and butterflies. Borage was the best for honey bees. Lavender and open-flowered dahlias were very attractive to bumblebees. Bowles mauve was the best for butterflies. But all attracted a range of insects. The least attractive flowering plant to insects was the pelargonium – a popular garden plant.

mason bee covered in pollen

But the study clearly showed that planting pollinator-friendly flowers is a no-cost, win-win solution to help the bees. The plants attractive to bees are just as cheap, easy to grow, and as pretty as those that are less attractive to insects. Garden plants do not have to be native to help most pollinating insects. Nectar, for example, is basically sugar and water, and so it is of value to British insects whether it is from a native garden plant or one from another part of the world. Lavender is from the Mediterranean and dahlias are from Mexico.

So helping bees in your garden is a no-brainer. Plant the right flowers and the bees will come!

Visit the Laboratory of Apiculture and Social Insects (LASI) website.


Photo credit: John Kimbler