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Phacelia nemoralis (Shade Phacelia)
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© Ed Alverson, some rights reserved (CC-BY) · iNaturalist

Phacelia nemoralis

Shade Phacelia

At a Glance

HabitUpright
FoliageDeciduous
Height3-5 feet (90-150 cm)
Width18-30 inches (45-75 cm)
Maturity2 years

Growing Zones

USDA Hardiness Zones

6 - 9
These zones indicate the coldest temperatures this plant can typically survive.
What's my zone? →
Frost Tolerancehardy

Key Features

Maintenancelow

Overview

A tall biennial to short-lived perennial reaching 3-5 feet (90-150 cm) tall from a basal cluster of leaves with one to several stout flowering stems. Basal leaves pinnately compound, 4-10 inches (10-25 cm) long, with 5-9 oval to lance-shaped leaflets, dark green and roughly hairy. Stem leaves smaller, similarly divided. The entire plant is densely covered with stiff bristly hairs that may cause skin irritation on contact in some individuals. Inflorescences scorpioid (tightly coiled at first, uncoiling as flowers open) cymes that elongate during bloom into spikes 6-12 inches (15-30 cm) long. Each flower 0.25-0.4 inch (6-10 mm) across, dull greenish-white to pale yellow-green with prominent exserted stamens that extend 0.3-0.5 inch (8-13 mm) beyond the petals, giving the inflorescence a fuzzy or feathery appearance. Capsules 0.15-0.25 inch (4-6 mm), ripening in late summer. Plants flower in their second year from seed and decline after flowering; self-sown seedlings establish stands.

Native Range

Native to the Pacific coast of North America from southern Alaska south through coastal British Columbia, Washington, and Oregon to northern California. Found in moist coniferous forests, shaded streambanks, and disturbed forest openings at sea level to 3,500 feet (1,070 m) elevation.

Suggested Uses

Commonly planted in shaded native plant gardens, woodland edges, and naturalistic forest understory plantings at 18-24 inch (45-60 cm) spacing. Self-seeding habit suits naturalistic plantings but may need thinning in formal settings. Bristly foliage causes skin irritation on contact in some individuals; in cultivation, the species is commonly grown at distance from frequently traversed paths.

How to Identify

Distinguished from related Phacelia species by tall stature (3-5 feet / 90-150 cm) and shade-tolerant habit, combined with dull greenish-white to pale yellow-green flowers (rather than the blue-purple flowers of most Phacelia). Inflorescences scorpioid cymes typical of the genus, with prominently exserted stamens. Foliage densely bristly-hairy with pinnately compound leaves of 5-9 leaflets.

Appearance

Size & Dimensions

Height3' - 5'
Width/Spread1'6" - 2'6"

Reaches mature size in approximately 2 years

Colors

Flower Colors

Foliage Colors

Fall Foliage Colors

Bloom Information

Bloom Period

~6 weeks
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May through July; lowland populations bloom in May-June, montane populations into July. Each spike holds open flowers for 3-4 weeks; full bloom in a stand extends 5-7 weeks.

Detailed Descriptions

Flower Description

dull greenish-white to pale yellow-green

Foliage Description

dark green

Growing Conditions

Sun Requirements

Requires 2-6 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight

Soil Requirements

pH Range5.5 - 7.0(Neutral)
357912
Soil Types
Drainagemoist

Water & Climate

Water Needs

Medium

Frost Tolerance

hardy

Time to Maturity

2 years from seed to flowering (biennial)

Care & Maintenance

Care Guide

Direct-sow seed in autumn for germination the following spring; seed requires cold-moist stratification of 8-12 weeks. Plants are biennial to short-lived perennial; expect a basal rosette in year 1 and flowering in year 2, after which most plants decline. Soils with high organic matter and consistent moisture support the largest plants; xeric sites yield smaller, lower-flowering specimens. Foliage causes skin irritation on contact in some individuals through bristly hairs, similar to other large Phacelia species. Slugs may damage emerging shoots in mild wet springs. Self-sown seedlings replace mature plants in established stands.

Pruning

Cut spent flower stems to the basal rosette after seed has dispersed in late summer to control self-seeding. The plant is monocarpic in most stands; flowering individuals die back after seed set. Volunteer seedlings can be thinned in autumn or early spring to maintain desired density.

Pruning Schedule

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summer

Maintenance Level

low

Container Growing

Minimum container size: 3 gallons

⚠️ Toxicity Warning

Unknown

Planting Guide

Planting Methods & Timing

Planting Method

direct sow