British gardeners are being encouraged by scientists to embrace weeds this summer as a means to support struggling honeybee populations. Research from the University of Sussex suggests that letting plants such as thistles, ragwort, and knapweed grow can provide essential food sources during the late summer months, a period identified as particularly challenging for bees.
According to the study, published in the journal Functional Ecology, honeybees experience their least productive foraging periods in July and August. During this time, fewer flowers are in bloom, and increased competition for nectar arises among various insect species. This scarcity can be exacerbated by heatwaves, which may reduce nectar production and disrupt plant flowering schedules.
"Our findings add to a growing body of literature indicating that late–summer is a particularly challenging season for pollinators," said Dr. Nicholas Balfour, a co-author of the study. "This is incredibly important, as this period of the year is when the vast majority of pollinator species are active and require forage to provision for their offspring."
The research, which gathered foraging data from over 1,200 honeybees and nectar data from more than 1,400 flowers in Brighton and Edinburgh, found that bee foraging is most efficient in spring. This is when insect-pollinated trees like horse chestnut, willow, and cherry typically bloom. However, the insects struggled to gather sufficient nectar and pollen in late summer.
Dr. Ciaran Harris, another co-author, explained that encouraging plants that bloom in late summer would be more beneficial for bees. "This could be achieved by planting late–summer blooming flowers, adjusting when lawns are mown, or being more tolerant of summer–blooming 'weeds' like thistle, ragwort, and knapweed," he stated.
The scientists noted that the findings likely apply to other pollinator species as well, as honeybees' varied floral choices serve as an indicator of overall nectar availability.
Professor Francis Ratnieks, also a co-author, commented that the results align with previous indirect studies. "These studies all point to late summer being the most challenging season for gathering nectar, and in doing so simplify the task of 'helping the bees'," he said.
Previous recommendations from experts have also urged gardeners to reconsider their approach to garden inhabitants, with some suggesting tolerance for slugs and snails to help restore ecosystems. This latest research highlights a similar shift in perspective, advocating for the ecological value of plants often considered weeds.