Phacelia tanacetifolia is often grown as a green manure and I have seen it several times planted by farmers as a cover crop on a patch of land that is otherwise unused. Green manures are swift-growing, nitrogen-rich plants that are grown for a short period of time and then dug back into the soil to improve nutrition levels, particularly useful for allotments and vegetable gardens where a rotational system is in place. Phacelia is one of the most attractive of the green manures, with pretty, pale lavender flowers unfurling from coiled spikes as the buds open, with long, spidery stamens that give the plant a hazy effect from a distance. An excellent plant for the wildlife garden, its nectar-rich flowers attract bees in droves - one of my lasting memories from last year was a walk that took me past a great field of it, and the low hum of the bees en masse was phenomenal. Native to California, Arizona and Mexico, it colonises dry, stony hillsides, and needs very little TLC to survive, as long as you give it an open spot where it can stretch out in the sunshine. It’s useful for a patch of ground that has been cleared, or for scattering in between other summer annuals, where it behaves a bit like borage, popping up informally wherever it chooses to seed.

You can either sow Phacelia in early autumn or any time in spring, broadcasting the seed and raking it gently in. Growing to about a metre tall, it will self seed everywhere if you let it, so be prepared to welcome it into your garden with open arms. Whichever way you look at this fast-growing annual, it is beneficial: its roots help improve soil structure; as a plant it grows quickly and suppresses weeds; its flowers attract bees and other insects; and when dug back into the soil, it helps improve fertility. What’s not to love?

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