Phacelia
Phacelia tanacetifolia
One of the finest bee plants — a green-manure and pollinator lure.
Spacing & sowing
- Plant spacing
- 9.8 in
- In-row spacing
- 7.9 in
- Between rows
- 11.8 in
- Square-foot density
- 4 per square
- Sow depth
- 0.2 in
Calendar (from your frost dates)
- Sow direct
- 14 days before the last spring frost
- First harvest
- 55 days after the last spring frost
- Harvest ends
- 14 days before the first fall frost
Growing
- Type
- Flower · Grown as an annual
- Botanical family
- Mixed / other
- Sunlight
- Full sun
- Watering
- Low
- Soil
- Any reasonable, well-drained
- Feeding
- Gentle all-organic
- Frost tolerant
- Yes
- Season
- Cool Season
- Harvest type
- Continuous Harvest
- Start from
- seed
Growth stages
- 0 d Sow seeds
- 10 d Germination
- 55 d Flowering
Harvest
- When
- Grown chiefly for bees and as green manure, but the curled lavender scorpioid flower spirals cut charmingly. Cut in cool morning in late spring–summer; for seed-saving or soil-digging-in, act before it self-sows.
- What to look for
- Cut for the vase when the fiddlehead spiral has 1–2 rows of open florets — it keeps uncurling in water. As green manure, cut down at full flower before any seed browns. Seed is ripe when the coiled heads turn brown and dry.
- How to harvest
- Snip stems with scissors into water at once (stems are soft); wear sleeves if sensitive — foliage can irritate skin. For green manure, chop at the base and dig in or compost.
- How often
- Successional sowings rather than repeat cutting give continuous flowers; a stand blooms hard for about 6 weeks. Cut whole plants down promptly if you don't want volunteer seedlings everywhere.
- Storing the crop
- Vase life 4–6 days, the spiral opening as it goes. Seed: dry whole brown heads in a paper bag, thresh, and store cool and dry — phacelia seed needs darkness to germinate, and keeps 2–3 years.
Pests & problems
- Aphids Small sap-sucking insects — greenfly, blackfly — that cluster on soft new growth and excrete sticky honeydew. Squash by hand, hose off with water, and encourage ladybirds and lacewings.
- Slugs & snails Ragged holes and silvery trails on seedlings and soft young growth, worst in damp weather. Use beer traps, wool pellets, or torchlight hand-picking; keep beds clear of daytime hiding places.
- Powdery mildew A white dusty coating over leaves and shoots when roots are dry but the air is humid. Keep plants watered and mulched, prune for airflow, and remove the worst leaves.
Garden allies
Beneficial predators that hunt this plant's pests — grow their favourite flowers nearby to recruit them. companion plant
- Garden birds Passeriformes
Both things are true: birds strip your currants and a brood of blue tits takes several thousand caterpillars out of one fruit tree in a fortnight. Net what you must and welcome them everywhere else — a nest box near the apples is worth more than a spray.
- Aphid midge Aphidoletes aphidimyzaHunts Aphids
A tiny midge whose orange maggots paralyze aphids and drink them dry, twenty or more each. Sold as a greenhouse biological control and resident outdoors wherever there are small nectar flowers and an unsprayed aphid colony to find.
- Assassin bug ReduviidaeHunts Aphids
A patient ambusher with a curved beak it drives into whatever it catches — caterpillars, beetles, bugs, and the occasional bee, so count it a generalist rather than a specialist. It will jab a careless finger too, so admire it and leave it be.
- Beneficial nematodes Steinernema & Heterorhabditis spp.Hunts Slugs & snails
Microscopic worms watered onto damp soil that hunt down soil-dwelling grubs and release a bacterium that kills them within days. Timing is the whole thing: warm, damp soil and a small target grub, which means late summer for most of what they are used against.
- Big-eyed bug Geocoris spp.Hunts Aphids
A stubby 3 mm bug with enormous wrap-around eyes, working the soil surface and the low foliage for aphids, mites, thrips and insect eggs. It is the main natural check on chinch bugs in a lawn and it is killed outright by insecticide.
- Centipedes ChilopodaHunts Slugs & snails
Flat, fast, one pair of legs to a segment — and a predator, unlike the slow round millipede it is constantly confused with. It hunts slugs, cutworms, springtails and woodlice by night under mulch and stones. Learn the difference and leave this one alone.
- Damsel bug NabidaeHunts Aphids
A slender, mantis-armed bug that grabs aphids, small caterpillars, and thrips in low crops and meadowy edges. Leave a strip of unmown grasses and flowers for it to overwinter in.
- Dragonflies & damselflies OdonataHunts Aphids
Aerial hunters that take mosquitoes, midges and small flies on the wing all day, and whose larvae spend a year or more clearing the same insects from the water. A pond with planted margins and no fish is the way to have them.
- Frogs & toads AnuraHunts Slugs & snails
A resident toad works the beds every night for slugs, cutworms, and weevils. Recruit them with water — even a sunken basin pond — plus damp shade and an upturned-pot toad house; skip the slug pellets that poison their prey.
- Green lacewing Chrysoperla carneaHunts Aphids
Its bristly larvae — "aphid lions" — impale aphids, mealybugs, thrips, and mite colonies, eating hundreds a week. Adults feed on nectar and pollen from small open flowers and overwinter in hollow stems left standing.
- Ground beetle CarabidaeHunts Slugs & snails
Fast, glossy night hunters that patrol the soil surface for slugs, cutworms, and root-fly larvae. Give them daytime cover — thick perennial edges, stepping stones, a log — and skip the tillage that wrecks their burrows.
- Hedgehog Erinaceus europaeusHunts Slugs & snails
A European animal, and worth saying so plainly: there are no hedgehogs in North America, and the ally that does the same night shift here is the toad, the opossum or the ground beetle. Where they do occur, cut a gap in the fence and skip the pellets.
- Hoverfly SyrphidaeHunts Aphids
Bee-mimicking flies whose legless larvae graze aphid colonies clean while the adults pollinate. A ribbon of shallow, nectar-rich flowers kept in bloom all season recruits wave after wave of them.
- Ladybird (lady beetle) CoccinellidaeHunts Aphids
The gardener’s favorite ally: adults and their alligator-shaped larvae each eat thousands of aphids, plus scale, mealybugs, and other soft-bodied sap-suckers. Grow flat, open flowers for the adults and never spray a colony that ladybird larvae are already working.
- Minute pirate bug Orius spp.Hunts Aphids
A pinhead-sized true bug that is the best natural check on thrips, and happily spears aphids, mites, and insect eggs too. It needs pollen when prey is scarce, so keep something flowering nearby.
- Parasitic wasps Braconidae & TrichogrammaHunts Aphids
Tiny, stingless wasps that lay eggs in or on caterpillars, aphids, and moth eggs — the white cocoons riding a hornworm are their calling card, so leave that caterpillar be. Umbel flowers with shallow nectar keep the adults fuelled.
- Praying mantis MantidaeHunts Aphids
A sit-and-wait ambusher that snatches caterpillars, beetles, and anything else that wanders close — friend and foe alike, so count it a mixed blessing. Tall, structured plantings give it perches and egg-case anchors.
- Rove beetle StaphylinidaeHunts Slugs & snails
Slim, quick beetles with short wing cases that hunt in soil and litter, taking root-fly eggs and larvae, fungus-gnat larvae, and mites. Mulch and undisturbed ground keep them resident year-round.
- Salamanders & newts CaudataHunts Slugs & snails
Damp-loving hunters of slugs, worms, woodlice and beetle larvae that spend the day under a log or a stone and work the beds at night. Companions to the toads: they want the same damp shade, the same log pile, and the same absence of slug pellets.
- Snakes & lizards Colubridae & PhrynosomatidaeHunts Slugs & snails
A garter snake works the beds for slugs and voles and a fence lizard clears grasshoppers off a sunny wall. Almost every snake a gardener meets is harmless and useful; give them a log pile, a warm flat stone and a bit of cover and they stay.
- Soldier beetle CantharidaeHunts Aphids
Soft-winged beetles seen mating on flower heads in high summer; adults and larvae both take aphids and soft grubs. Open composite flowers are their landing pads and hunting grounds.
- Spiders AraneaeHunts Aphids
Webs, ambushes, and night patrols make spiders the garden’s steadiest generalist predators, taking whatever flies or crawls past. Mulch, ground cover, and undisturbed corners keep the population dense.
Germination & growth
- Germination temp
- 50–77°F
- Min soil temp
- 46 °F
- Photoperiod
- day neutral
Did you know?
Rated among the very best bee plants in the world and often sown as a green manure.
The Cottage Garden Companion — the gardener's herbarium at cottagegardencompanion.com