So easy it is sown as green manure, this beautiful plant is a magnet for bees too.
Phacelia are not often grown in European gardens except for P. tanacetifolia. There are almost 100 species, native to North and Central America with a concentration of species in California. They are in the borage family and have typical, five-petalled flowers, with the petals united at the base, and often long stamens, especially so in P. tanacetifolia. The foliage varies but in this species the leaves are finely divided, just like tanacetum, would you believe.
This is a hardy annual and can be sown where it is to grow. In fact it is so easy to grow that it is often recommended as a green manure, to be dug in before it flowers. I have never managed to do this though because the flowers are so lovely. Quite quickly from seed the plants start to bloom and, according to how well the plants are grown, they bloom for six weeks or more. The flowers are a soft blue and produce abundant pollen. Bees are attracted to the flowers but, from observation, they seem intent on collecting pollen rather than nectar. They rush over the flowers and rarely seem to probe for nectar. Hoverflies are also attracted and also butterflies, to a lesser extent.
This plant can be sown in spring and also in September to overwinter. Well grown plants can reach 1m high when full bloom and plants usually selfseed freely if allowed to die naturally. Because it is so easy to grow this is a plant that can be combined with other hardy annuals such as poppies, larkspur, calendulas and nigella. The seeds need darkness to germinate so cover the seeds after sowing. I am not giving my usual ratings to any of these annuals but this is one that I would really recommend – just sow a sprinkling in any bare patches in borders from March to June and again in September.
The other phacelia that is readily available is P. campanularia. This pretty, low plant is native to California, in the Mohave and Sonoran deserts but, fortunately for us in wetter climes, it is a very adaptable little plant and will cope with most conditions. It is a sprawling, almost straggly, plant with reddish stems and deep green, round-ish leaves. The joy of the plants is the upward-facing, intense, gentian-blue flowers enhanced by five cream stamens. As might be expected, this is a plant for a sunny spot and it thrives in dry soil. If it has other plants to clamber against it can reach 30cm high but otherwise 20cm is more typical. One plant can be a bit lost so make sure you sow plenty. Alternatively, mix it with orange calendulas or vibrant Californian poppies for a more authentic and dazzling display.
Just a note that some people are sensitive to the hairs on the plant which can cause a rash. This is common among the Boraginaceae. I get annoying rashes from comfrey and echiums but phacelia does not bother me.