Phacelia tanacetifolia

Phacelia tanacetifolia is a versatile plant that is
used extensively in Europe, both as a cover crop
and as bee forage. It is also being increasingly
used in California – especially in vineyards.
Phacelia is quick to grow and flower and grows
well in dry soil. 

It does a good job of limiting
nitrate leaching when planted in early fall. It
winterkills at about 18°F. In cooler regions, it can
be used as a between cash crops cover crop in the
summer. Phacelia is listed as one of the top 20
honey-producing flowers for honeybees and is also
highly attractive to bumblebees and syrphid
(hover) flies. Phacelia's habit of flowering
abundantly and for a long period can increase
beneficial insect numbers and diversity, because it provides high quality nectar and pollen. It's
also useful as a cut flower with its unusual and attractive blooms, strong stems, and long vaselife.
Because phacelia germinates well at cool temperatures and grows quickly, cut flowers can
be available by mid-spring.

Value to Insects
Phacelia is highly attractive to honeybees, bumblebees, and syrphid flies, and these insects are
valuable pollinators. Syrphid fly larvae are voracious feeders on aphids and young caterpillars.
Phacelia is also reputed to attract other beneficial insects, such as parasitic wasps and minute
pirate bugs. It provides both pollen (for protein – needed for egg production) and nectar (for
carbohydrates – needed for energy).
Insectary plants are those with high volume, quality nectar and/or pollen that are extremely
attractive to beneficial insects. They are planted for the primary purpose of attracting pollinators,
and predators and parasites of pest insects. Phacelia's habit of quick growth and long flowering
make it highly suitable as an insectary plant. It can be succession sown so that it is in flower all
season or it can be sown at a specific time to build up beneficial insect populations in
anticipation of their need to control a crop pest.

One caution – if you have a large area of phacelia planted, time the planting so that phacelia
flowers are not blooming when you need a crop pollinated. Phacelia flowers are so attractive to
pollinators that the flowers would compete successfully for pollinator services against most other

flowering plants. 

Use as a Fall/Winter Cover Crop and/or Mulch
Phacelia may be suitable as a winter-killed cover crop when a heavy crop residue is not needed
in the spring. Research in other regions shows phacelia has the potential to produce abundant
biomass and does a good job at catching excess nitrates before they leach into groundwater.
Phacelia winter-kills at about 18ºF, and the residue breaks down quickly. Its use as a fall/winter
cover crop may be appropriate when it will be followed by a vigorous cash crop (e.g. potatoes) in

early spring. 

Phacelia has proven its usefulness as a food source for pollinators and other beneficial insects. It
has also proven its value as a cover crop in other regions of the world. It is largely untested in
the mid-Atlantic. While clearly not the cover crop for every situation, it may be a good choice in
some situations – especially when there is a desire to attract beneficial insects. We need more
information about this potentially useful plant and on how it performs in this part of the world.
We also need information about phacelia's usefulness as forage. Several publications mentioned
forage as a use, and phacelia has a nitrogen content of 4%, but little else is known about its

suitability as animal feed.