Phacelia (lacy phacelia) Phacelia tanacetifolia
Phacelia (lacy phacelia) (Phacelia tanacetifolia) is an annual flowering plant in the Hydrophyllaceae family, native to California, Arizona, Nevada and northern Mexico. It grows 40–90 cm (16–35 in) tall and 25–40 cm (10–16 in) wide, wants full sun and low water, and is hardy to about -6 °C (21 °F). Space plants about 15 cm (6 in) apart.
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Phacelia (lacy phacelia) at a glance
| Type | Annual flowering plant |
|---|---|
| Family | Hydrophyllaceae |
| Mature height | 40–90 cm (16–35 in) |
| Mature spread | 25–40 cm (10–16 in) |
| Spacing | 15 cm (6 in) centre to centre |
| Sun | Full sun, at least 6 h of direct sun a day |
| Water | Low; drought tolerance moderate, waterlogging tolerance none |
| Soil pH | 6–8 |
| Cold hardiness | About -6 °C (21 °F) once established (roughly USDA zone 9) |
| Heat stress | Likely above about 32 °C (90 °F) |
| Flowering | about 6–10 weeks after planting, for 4–7 weeks |
| Days to maturity | About 80 days from planting |
| Wind tolerance | Low |
| Pollinator value | High |
| Edible | Not grown as food |
| Native to | California, Arizona, Nevada and northern Mexico |
| Common in gardens of | 🇺🇸 United States, 🇲🇽 Mexico, 🇬🇧 United Kingdom, 🇮🇪 Ireland, 🇩🇪 Germany, 🇳🇱 Netherlands, 🇫🇷 France, 🇵🇱 Poland |
Is Phacelia (lacy phacelia) toxic?
- People: mildly toxic
- Cats: not known to be toxic
- Dogs: not known to be toxic
- Parts: bristly hairs
Not poisonous, but the bristly stems can cause a contact rash in some people.
If a child or pet may have eaten part of a plant, call a poison centre or vet straight away.
Companion planting: what to grow with Phacelia (lacy phacelia)
No well-documented helpful pairing. Group it with plants that like full sun and low water.
Questions about Phacelia (lacy phacelia)
- How far apart should I plant Phacelia (lacy phacelia)?
- About 15 cm (6 in) apart, centre to centre. A mature plant spreads 25–40 cm (10–16 in).
- Does Phacelia (lacy phacelia) need full sun?
- Full sun: at least 6 hours of direct sun a day.
- How much water does Phacelia (lacy phacelia) need?
- Low water. Drought tolerance is moderate and waterlogging tolerance none.
- How cold-hardy is Phacelia (lacy phacelia)?
- It tolerates about -6 °C (21 °F) once established, roughly USDA zone 9. As an annual it is usually planted out after the last frost.
- When does Phacelia (lacy phacelia) flower?
- About 6–10 weeks after planting, for 4–7 weeks.
- Is Phacelia (lacy phacelia) poisonous to cats and dogs?
- For cats it is not known to be toxic; for dogs not known to be toxic; for people mildly toxic. Not poisonous, but the bristly stems can cause a contact rash in some people.
- What grows well with Phacelia (lacy phacelia)?
- There is no well-documented companion pairing for Phacelia (lacy phacelia). Group it with plants that like the same sun (full sun) and water (low).
Sources and evidence
Evidence grade A (A: strong evidence).
- Plants of the World Online (taxonomy, native range), Royal Botanic Gardens, Kew
- Calflora: information on California plants, Calflora (non-profit database), Berkeley, California
- RHS Find a Plant (plant profiles and growing guides), Royal Horticultural Society
Notes and assumptions
- A hardy annual: sow where it is to flower in autumn or early spring, thin the seedlings, and let some plants set seed.
- Curled heads of lavender-blue flowers much loved by honeybees and hoverflies. On allotments it is sown as a fast green manure and dug in before it flowers; it belongs to no vegetable family, so it fits any rotation.
Reference values for planning, not horticultural, veterinary or medical advice. Varieties, soils and local climates differ: check with a local nursery or extension service.
Related plants
- Sunflower Helianthus annuus
- French marigold Tagetes patula
- English lavender Lavandula angustifolia
- Zinnia Zinnia elegans
- Cosmos Cosmos bipinnatus
- Purple coneflower Echinacea purpurea
- Foxglove Digitalis purpurea
- Daffodil Narcissus pseudonarcissus