Posted: Friday 16 May 2014
by Kate Bradbury
Cycling through the allotment last week, I stopped at a plot filled with tall blue flowers. It was flowering scorpionweed, Phacelia.
Cycling through the allotment last week, I stopped at the edge of almost an entire plot filled with tall blue flowers. It was such a striking but alien sight for this time of year. I normally associate the colour with low-growing bluebells or later-flowering delphiniums or lupins, not an allotment crop in early May in north London. What were my neighbours growing?
On closer inspection I realised it was merely flowering scorpionweed, Phacelia tanacetifolia, which had presumably been sown as a green manure and then forgotten about. But in the dusky evening half-light the blue flowers almost shimmered, and they were still alive with the buzzing of bees. It might have been alien but it was incredibly beautiful – I’d found an oasis in a desert of neat rows of garlic and broad beans.
Despite not recognising it at first, phacelia is one of my favourite bee-friendly flowers (although ‘friendly’ doesn’t really do it justice – I think the bees would marry phacelia if they could). I grew some in a large container a couple of years ago. Rather than grow tall like those on my neighbour’s allotment plot, the plants spilled over the edge like trailing lobelia, and the bees ignored everything else until they’d had their fill.
Native to south-western United States and Mexico, phacelia is widely used all over the world as a green manure. It’s ideal for spring/autumn sowing as its seeds germinate in cold temperatures and it overwinters well, and it forms a dense matt that suppresses the growth of weeds. Its root system is also said to improve soil structure.
But it’s the flowers that interest me. Long, coiling inflorescences of deep-blue nectar-rich blooms appear in succession above fern-like foliage, providing bees and their friends with a long season of nectar and pollen. Such is its attractiveness to bees that it is used by one of Britain’s rarest species, the great yellow bumblebee, Bombus distinguendus, although you’re not likely to attract one to your garden unless you live in the far north of Scotland.
Hopefully my allotment neighbours will continue to forget about their crop of green manure, at least until I can relieve them of some seeds. I’ll scatter these on my plot and maybe by summer I too will have an oasis of shimmering phacelia flowers masking my neat rows of garlic and broad beans. I hope so. If not for me then for the bees.