perennialN. America Native

Silky Phacelia

The Story

Plant Bio

Phacelia sericea is a low-growing, clump-forming herbaceous perennial native to the subalpine and alpine zones of western North America. Rising from a woody, taprooted base, the upright stems bear deeply divided, silvery-green leaves covered in dense, silky hairs.

The dark purple or blue bell-shaped flowers feature prominent, long-protruding stamens with bright yellow anthers, packed into dense, cylindrical, bottlebrush-like clusters. The persistent silvery foliage retains its metallic sheen throughout the growing season, providing stark contrast against rocky substrates.

Uses & Benefits:

Provides striking metallic silver foliage and dense, violet-blue bottlebrush flower spikes suitable for alpine rock gardens.

Thrives in barren, nutrient-poor, and gravelly soils where other garden perennials fail to survive.

Highly attractive to native bees and other specialized mountain pollinators, offering high-value forage.

Essentials

At a Glance

Plant Type

Perennial

Height

16"

Width

12"

Light

Full Sun

Zones

4, 5, 6, 7

Water

Low

Humidity

Low

Lifespan

Perennial

Native To

North America

Toxicity

Skin Irritant

Bloom period

Late spring – Summer

In flower about 4 months of the year

Planting

How to Grow

Select a site in full sun with exceptional drainage, such as a rock garden, scree bed, or gravel-filled crevice.
Excavate a planting hole and backfill with a lean, mineral-rich mixture of gravel, sand, and minimal grit, avoiding organic compost or rich loam.
Position the plant so the crown sits slightly elevated above the surrounding soil level to prevent water accumulation.
Water sparingly during the establishment phase, then withhold supplemental irrigation entirely once the taproot is established.

Pro Tip

Plant in pure gravel, talus, or scree with sharp vertical drainage to prevent water from pooling around the woody crown, as any moisture retention in rich loam will rapidly trigger fatal rot.

Keep It Thriving

Care Guide

Do

Grow in lean, nutrient-poor mineral soils with excellent drainage.
Provide full sun exposure to maintain the compact, silvery growth habit.
Wear gloves when handling the foliage to avoid potential skin irritation from glandular hairs.

Don't

Do not apply fertilizers, which cause weak, floppy growth and shorten the plant's lifespan.
Do not plant in heavy clay or moisture-retentive soils that trigger crown rot.
Do not overwater or irrigate during the humid summer months.

Seasonal Care Calendar

Task	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Deadhead
Plant
Propagate
Winter Prep

Watch Out For

Pests & Diseases

Common Pests

Common Diseases

In the Garden

Landscape Uses & Companions

Landscape Uses

Rock GardenAlpine Scree BedGravel GardenCrevice Planting

Companion Plants

Eriogonum ovalifolium Penstemon davidsonii Sedum lanceolatum

Multiply

Propagation Methods

Good to Know

Common Questions

Silky Phacelia questions

What zones can Silky Phacelia grow in?

Silky Phacelia is hardy in USDA Zones 4–7. Inside that range it survives winter in the ground; outside it, grow it as an annual or a container plant you protect.

Is Silky Phacelia deer resistant?

Not reliably. Deer may browse Silky Phacelia, especially tender spring growth — plan on repellents or fencing where pressure is high.

When does Silky Phacelia bloom?

Silky Phacelia typically blooms in late spring through summer. Exact timing shifts a week or two with your zone — Sow's bloom calendar maps it to your garden.

Does Silky Phacelia need full sun?

Silky Phacelia does best in full sun (6+ hours).

Is Silky Phacelia drought tolerant?

Yes — once established (usually after the first full season), Silky Phacelia handles dry spells with minimal watering. Water deeply its first year to build the root system that makes that possible.