How to grow phacelias

Phacelia is a fast-growing annual grown less for eating than for what it does for the rest of the garden: fern-like, feathery foliage rises quickly into fiddlehead-shaped clusters of purple-blue flowers that pull in bees and other pollinators from the moment they open. Gardeners sow it as a cover crop between vegetable plantings or tuck it into a border specifically to draw pollinators toward nearby crops, since it blooms fast and fills bare soil before weeds get a foothold. It asks for little beyond full sun and average drainage to establish.

The hardest part of growing phacelia well is knowing when to cut it down. North Carolina State Extension notes that because phacelia self-seeds so easily, it can become weedy if left standing. A second-year gardener who lets a stand keep flowering past its peak, enjoying the pollinator traffic a little longer before turning it under, misses the point where the earliest blooms have already set viable seed. The following season brings volunteer seedlings scattered through beds meant for something else, turning a cover crop chosen to build soil into one more thing to weed out all summer.