Look at the difference a year makes. Last August, the planters on the 8th floor rooftop at Bread Street had been devastated by drought. Even drought-resistant plants like Rosemary and Salvia had died in the 6 week drought and heatwave of summer 2022. (We didn’t think they’d need an irrigation system). Only the Sedum and Kniphofia showed any life. But unbeknown to us Verbena bonariensis had seeded everywhere and with the dead shrubs removed, there is now a pretty jungle of this resilient, drought-tolerant voracious self-seeder taking over the west-facing planter. While it’s feeding honeybees and some bumblebees, we will need to remove much of it to allow other flowers to thrive to feed a variety of bees. We will rehouse it on another rooftop.
Last September 2022, myself and Alex pulled up the dead Rosemary shrubs (no mean feat), and planted many new shrubs and perennials like Coreopsis (Uptick), Stachys byzantina (Lamb’s Ear) and Echinops (Globe thistle). They are all drought-tolerant but we also installed an irrigation system just in case we had another very dry spell. The planters we inherited are shallow so the plants can’t dig down deep into soil for water when it doesn’t rain for weeks.
In October 2022, after planting lots on small plug plants we mulched the two planters with bark chippings to prevent too many weeds taking over and to keep in moisture.
By spring 2023, we had wallflowers and a new, small Rosemary plant flowering. And we installed a couple of bee hotels for solitary Red mason bees (Osmia bicornis). We introduced a few cocoons and soon the bee hotels tubes were occupied by a new generation of Red mason bees laying their eggs and provisioning them with pollen collected from flowers on the rooftop.
By June 2023, the kniphofia we thought was practically dead a few months earlier was looking spectacular and there was lots more of it. The lamb’s ear we’d planted was already flowering along with the Coreopsis (Uptick) much to the buff-tailed bumblebees’ delight. When Konstantinos, the ecologist from Pollinating London Together visited to do a bee survey, it was a boiling hot day and there were mainly honeybees and Buff-taield bumblebees flying. But with the aid of a net, glass tube and hands lens we were very excited when we identified small Green furrow bees (Lassioglossum morio) foraging 8 floors up in the City of London on Epilobium hirsutum (Hairy willowherb).
By July, 3 plants we’d put in as plugs in September (supplied by Rosybee) : L-R Teucrium hircanicum (Caucasian germander), Eupatorium (Hemp agrimony) and Eryngium planum (Sea holly) were looking magnificent on the east-facing planter.