April 2023

This area of roof 12 storeys above the City was originally earmarked for honeybee hives, but we explained to the client (a large real estate managing agent) that hives don’t do well in the City due to many factors including lack of forage, We suggested they transform the area (25m2) into a bee garden for wild solitary bees and bumblebees to boost biodiversity. They agreed. So we made wooden raised beds earlier this year to hold 300mm of soil/lecca, fitted a drip irrigation system in case of drought and on 5 April 2023 myself and Alex finally got up on the roof to plant a variety of tough, bee-friendly shrubs and perennials that will sequentially bloom from later this month through to autumn. We decided that the first planter would contain plants that flower late spring, the second planter by mid summer, and the third for late summer plants.

I hope the depth of soil, the bark chipping we used as mulch and the irrigation system will prevent the roots drying out and give the plants plenty of room to grow and spread.

Plants include:

• Rosemary (Rosmarinus officinalis ‘Prostatus Group’ and Rosmarinus officinalis ‘Miss Jessopp’s Upright’)
• Perennial Wallflowers (Erysimus ‘Red Jepp‘)
• Hebes (pinguifolia ‘Sutherlandii’ and pinguifolia ‘Pagei‘)
• Lavender (Lavandula intermedia x ‘Edelweiss’)
• Vipers bugloss (Echium vulgare)
• Perennial cornflower (Centaurea nigra)
• Lamb’s ear (Stachys byzantina)
• Korean mint (Agastache rugoso)
• False dittany (Ballota pseudodictamnus or pseudodictamnus mediterraneus)
• Sedum Autumn Joy (Hylotelephium ”Herbstfreude’)

We’ve also scattered seed balls over one of the fourth planters to create a wildflower raised bed. I’ve never tried this before, but because it’s a rooftop that is not used by staff or clients, I think we can get away with experimenting a bit, rather than having to focus on aesthetics. If the seeds don’t take, we can always plant more shrubs. Maybe an Strawberry tree (Arbutus unedo) for winter forage.

As well as bee-friendly forage throughout the spring and summer, we are putting in 2 x bee hotels for cavity nesting solitary bees. It will be interesting to see if we get any nesting so high up.

I will be visiting each month to maintain the planters and monitor the visiting bees so watch this space.

Summer 2023

Late summer planter full of Korean mint (Agastache rugoso) and wild flower planter with red poppies

Bees seen in the first year:

1. Honeybees (lots from a neighbouring rooftop hive)
2. Red mason bees on the wallflowers – we introduced some cocoons which hatched and the bees were foraging on April/May blooms. (pictured left)
3. Common carder bees foraging on Echium vulgare in mid summer and Ballota (pictured right) in late summer.

A year on…..end of Feb 2024

The spring planter is blooming in late February with Wallflowers and Rosemary. It is looking a bit crowed. I think I put too many wallflower plants in! The mid summer planter is looking neat and tidy and ready to bloom in May/June.

The late summer planter has a few gaps as a couple of things didn’t do well. I may add a second Ballota as it is thriving. The wildflower meadow looks interesting. The Rosemary plant in the middle will provide early forage as wildflowers themselves don’t feed bees until mid summer.

The Centaurea nigra looks as if it is about to bloom (end of Feb!) and the electric blue Muscari armeniacum (Grape hyacinth) bulbs I planted in the autumn are about to appear. And the bee hotels, which I didn’t remove have a number of plugged tubes so it will be interesting to see when the adult males start to emerge.

We’ve had such a wet winter that I’ve not yet turned the watering system back on. I will keep an eye on the rainfall over the next few weeks to judge when it needs to.