Eight months after we planted lots of new flowers (in response to the drought in 2022) on the roof 8 storeys up on Bread Street in the City, many are thriving, and have been joined by some blow ins – flowers that have arrived another way. Birds have deposited the seeds, or they’ve been blown in -like the yellow, dandelion-like flower above and the patch of Red dead-nettle below (middle), which is important food for long-tongued bees in spring, like Hairy-footed flower bees and Common carder bees. The red campion is back, despite removing most of it as it was taking over, and I want to have a diversity of flowering plants throughout the year to feed bees, not a dominant few.

I realise that I can’t just let the roof do it’s own thing, or else the sunnier planter would have been covered with nothing but Red hot poker (kniphofia). It absolutely loves it up there – in the heat, the wind, the cold, the rain. It is the hardiest plant I’ve ever come across.

It will be interesting to see if we see more bees visiting this summer than last year when there was much less diversity of flowering plants. In summer 2023, the survey of pollinators on the roof by Pollinating London Together found a furrow bee on Willowherb (Epilobium) – another blow in – as well as less interesting honeybees and Buff-tailed bumblebees.

PL’s  Greenspace Habitat Survey 2023 scored the roof 14/20. It scored 80% on diversity of flowers for pollinators. I’m hoping for 100% this year. But only scored 3/8 for number of pollinator species found on the days of the survey. I would argue that one day was too hot for most pollinators, and another was too windy. But they are the extremes that pollinators face on a rooftop in the City of London during the summer.

The first 2024 PLT survey is scheduled for 23 May, so let’s see how the roof fares compares to last year. I think it will be much more attractive to bees if the conditions are good.