Phacelia - or purple tansy - is an annual flowering plant that is related to borage. It has the same hairy leaves and stems as borage and shares its attractiveness to bees in particular as well as hoverflies and other beneficial predatory insects. The blue flowers are rich in nectar and pollen and for this reason phacelia is often sown as a ‘bee crop’ to provide food for bees as well as to attract them to other crops that need pollinating. It is also sown ‘en masse’ as a weed-suppressing cover crop. In our gardens, phacelia can perform the same role as a bee beacon - as well as helping to boost the numbers of predatory insects that can help to control sap-sucking pests like aphids. Phacelia plants usually flower from spring right through summer. Phacelia can grow to around knee height.
Companions Cucumber, tomato, cabbage, kale, broccoli
Sow or plant in early spring and summer countrywide.
Phacelia grows well in full sun as well as partial shade.
Phacelia grows well on most soils that have reasonable drainage and do not get too water-logged. If your soil is sticky then dig in coarse sand or fine pumice to help improve drainage – or plant phacelia in a half-barrel, tyre stack or pot.
Best sown straight into the garden in early spring. Seeds can be sown a finger-tip deep in trays or punnets filled with seed compost but are best sown directly into beds and planting areas where soil has been prepared by being well dug.. Thin seedlings as they develop so that plants end up with about one or two hands’ lengths between them.
If you decide to sow into punnets and trays then transplant your seedlings when they are about a finger’s length in height and the weather has settled and is reliably warm and sunny, plant seedlings at an average spacing of a good hand’s length to a forearm apart. I usually dot them around the vegetable garden and plant them on bed corners and at the end of rows.
Water young seedlings in dry periods. Once they are established and starting to grow you shouldn’t need to continue with watering unless weather is persistently dry and your soil dries out. Plants will wilt to let you know its time to get the watering can out.
Phacelia can be used as a cut flower. Picking flowers encourages more to be produced so enjoy them in displays.
As an annual, phacelia will set seed in autumn and then die-off at the onset of winter. Allowing phacelia to flower and self-seed means you’ll be rewarded with a range of plants in all sorts of unexpected places next spring and summer. When you spot small seedlings in the spring you can simply lift them with soil around their roots and re-position them where you want them. If you don’t want plants to self seed then dig them into your soil as a green manure after flowering or cut down and add to compost heap. To save seed, allow the pods to dry first on plants then collect in a bag and pop them open to release their seeds. Seeds can be stored until the following spring.