It’s been a summer of two halves on the eight floor of Bow Bells House. And one that I want t share some lessons from, as to how to manage a rooftop ‘wild’ garden for bees and other pollinators. It went from looking the best it’s ever looked in June and July, to one of the worst in August when ‘weeds’ took over and water-deprived plants set seed early leaving no flowers in bloom to feed bees. Here I take you through each month:

April

Rosemary and Halimium ‘April Sun’, an RHS awarding winning rock rose, were doing well and attracting Hairy-footed flower bees, and Scabious was feeding Red mason bees. But the sprinkler watering system wasn’t working so well as it only reaches some of the planter, plus it’s too visible.

May

Erigeron Glaucus ‘See Breeze’ was out and mobbed by honeybees, along with Red hot pokers and early salvias. We saw Early bumblebees (Bombus pratorum), Red mason bees (Osmia bicornis), Green furrow bees (Lasioglossum morio) and we created a sand mound for ground-nesting mining bees with the help of ecologist Dr Konstantinos Tsiolis of Pollinating London Together, who conducts the spring/summer pollinator surveys. We put in a new soaker hose system and because it was a dry, warm spring, we had 90 minutes of water every night. Was that too much? It only dribbles out water, and again didn’t quite reach all the plants.

June

We paid a visit on June 20 to check the irrigation, as a heatwave was forecast. The combination of good weather and irrigation had led to an explosion of colour on both roofs. Comfrey, Veronica, Lamb’s ear on the east planter and Verbascum. Rose campion, Salvia and Erigeron on the west – all blooming early. The only downside was that the sand mound was now overshadowed by plants (not good for mining bees).

Went back on June 27 for 3rd pollinator survey and both planters look the best they have ever looked. Variety of plants and colours. Furrow bees on yellow dandelion-like flowers, and Wool carder bees on Lamb’s ear, among others.

July

I was contacted by a film production company who want to film on a bee-friendly rooftop in London for a major two-part series on bees being broadcast in 2026. Because Bow Bells House was looking so spectacular and has the view of St Paul’s, I suggested they film it. After a recce on 1 July, they loved it. They came back and filmed a segment in early July, hopefully with Wool carder bees etc (I couldn’t be there the day they filmed as I was running a workshop in Manchester).

On July 25, I went back with film maker, Jonathan Goldberg, to make a short film about Urban Bees work – that will appear on our new website. The rooftop was still looking great, especially the east side with Calamint, Willowherb, Eupatorium, Rudbeckia all looking fantastic. BUT it was clear it could have done with some maintenance. Overwhelmed by the task and the heat, I decided to put that off. The only maintenance myself and Brian had done, starting, back in May was to pull up any Fleabane we saw (there was lots and lots) before it flowered and set seed, and to chop off the Red hot poker seed heads. As it turned out that was far from enough!!!!

On that day we had to wear PPE (Hard hats, hi-vis vests and boots) as everything on the roof (except the planters) is now being ripped out as part of Bow Bells House extensive refurb – and no one had told the guys not to rip out our excellent watering system just as another heatwave was forecast. Contractors, Ikon, were very apologetic, especially when I said I’d be contacting the boss, Debbie at Fabrix. She responded to my distressed immediately (on a Friday night) and said it would be sorted out. It was…

August

6 August – they reinstalled the water, taps and a timed irrigation system and attached it to our soaker hose. It didn’t appear to be on, but that was why we were visiting, to make sure it was attached Ok and to put the water back on. However, even though the roof was still looking amazing, especially the agapanthus, salvia, perovskia on the west side, there was evidence that ‘weeds’ were taking over on the east side along with the Eupatorium, which had hugely spread. This is where I mad a BIG MISTAKE – the weeds seemed to be thriving around the soaker hose pipe, so I decided we should try 2 weeks with no water and see if that reduced the ‘weeds’. However, what I forgot (schoolgirl error), was that drought-stressed plants vigorously set seed to ensure they reproduce. So I was going to be in for a shock 2 weeks later – one of which was a heatwave with not a drop of rain.

August 22 – What a difference water makes!!!! In just 2 weeks with no water, plants had gone over much quicker and set seed and there were very few flowers blooming. So no food for bees! Everything looked brown and dry, including the Erigeron and it was impossible to see lavender, teucrium and veronica which were hidden in a cloud of fluffy Eupatorium and Willowherb seeds, and dead thistles.

We delayed the fourth and final pollinator survey of the year until the watering system had gone back on for a week. Instead of a survey, I spend the afternoon ripping up Willlowherb, whose clouds of seeds went everywhere! I put the water system on for 30mins every 12 hours. And there was rain too over the next week.

August 29 – 2 full days and 25 rubble bags later full of Eupatorium, Willowherb, Thistles (ouch), grasses and deadheading plants, and there are now big gaps in the planters, but I can fill those with a trip to a garden centre for late-flowering blooms. I can now see the Rosemary again, lavender, teucrium, some of which is still flowering ( I cut the purple tail seed heads to encourage more), and the pollinators are coming back. The Erigeron is still very brown, which isn’t good for the furrow bees, bu the salvia’s recovered and is buzzing with bees when it’s not raining….

Common carder bees (Bombus pascuorum) on Teucrium ‘purple tails’ and this amazing Hummingbird hawk-moth on the salvia. There were honeybees too. However, because of the intermittent heavy showers, we delayed the final pollinator survey still further.

September

After a lot of rain and additional regular irrigation, plus new plants to provide late nectar and pollen including Agastache, Coreopsis and Campanula – and yet more weeding – the planters are better fulfilling their function to provide a diversity of year-round flowers to feed different species of bees and other pollinators in the City of London.

Konstantinos was finally able to do the last pollinator survey of the survey in between the heavy, autumnal downpours.

LESSONS LEARNED

1. Don’t deprive flowers of water, especially during a drought as they go to seed quicker and there’s no flowers for the bees to feed on.
2. Don’t put off maintenance when a garden is looking at it’s best. It’s than that you need to be maintaining it.
3. Don’t let certain ‘weeds’ or invasive plants take over. As well as the fleabane, I should have been pulling up Willowherb, some thistles and the grasses and more Red hot poker seedlings which have taken root all over the west planter again, like sycamore seedlings.
4. A low maintenance, wildlife garden, does need at least a full day of maintenance during the summer months.
5. When you pull up the ‘weeds’ , big gaps are left, so I need to think more about bee-friendly ground cover that will work on the east facing planter and the west facing planter to help suppress the ‘weeds’ next spring and more importantly summer.