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Phacelia crenulata

notch-leaf scorpionweed

Boraginaceae

Southwestern United States and northern Mexico

Attracts Pollinators Attracts Butterflies Deer Resistant Drought Tolerant Fragrant (strong)

Native to North America

SunFull Sun

WaterLow · drought-tolerant

Overview

Phacelia crenulata, the notch-leaf scorpionweed, is a desert annual in the Boraginaceae growing 6-32 inches (15-80 cm) tall and 6-18 inches (15-45 cm) wide, with erect, often reddish, glandular-hairy stems. The grey-green leaves are 1-4 inches (2.5-10 cm) long and divided into rounded, scalloped, or notched lobes, and the whole plant is coated in sticky glandular hairs with a strong, pungent scent. From spring the stems carry coiled, scorpion-tail clusters of bell-shaped flowers about 0.3 inch (8 mm) long, blue-purple to violet, with pale throats and stamens that protrude well beyond the petals. The coils uncurl as the flowers open in sequence from the base. It grows in open desert, on sandy and gravelly flats, washes, slopes, and roadsides, often appearing in large numbers after wet winters. The glandular hairs cause an itching, blistering skin rash in many people, similar to the reaction to poison ivy. As an annual it dies after seeding, persisting only through the seed bank.

Native Range

Native to the southwestern United States and northern Mexico, across the Mojave, Sonoran, and Great Basin deserts from California and Nevada to Utah, Arizona, and New Mexico. It grows in open desert scrub, on sandy or gravelly flats, washes, rocky slopes, and disturbed roadsides.

Suggested Uses

Used in desert and native wildflower gardens, dry meadow seedings, and naturalised plantings on sandy or gravelly ground, sown in autumn and spaced about 10 inches (25 cm) apart. It suits low-water desert plantings and pollinator gardens for bees. The skin-irritating foliage makes it poorly suited to paths, play areas, or beds that need frequent handling.

How to Identify

Recognised by sticky, strongly scented glandular foliage, grey-green leaves with scalloped or notched lobes, and coiled, scorpion-tail clusters of blue-purple bell-shaped flowers whose stamens stick out beyond the petals. The notched leaf margins and pungent, glandular stems separate it from smooth-leaved phacelias. Contact with the hairs can irritate skin.

Appearance

Size & Dimensions

Height6" - 2'8"

Width/Spread6" - 1'6"

Colors

Flower Colors

Foliage Colors

Bloom Information

Bloom Period

~6 weeks

Spring

Flowers open in spring, mainly March through May, with timing and abundance tied to winter rainfall. The coiled flower clusters unroll gradually, so a plant blooms over several weeks. In dry years plants are small and flower briefly, while wet winters bring tall plants and mass bloom.

Detailed Descriptions

Flower Description

blue-purple to violet

Foliage Description

grey-green

Growing Conditions

Sun Requirements

SunFull Sun

Requires 6-12 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 Range6.5 - 8.5(Alkaline)

357912

Soil Types

sand rocky loam

Drainagewell drained

Water & Climate

Water Needs

Low

Drought Tolerance

Drought tolerant when established

Care & Maintenance

Care Guide

Grows in full sun in fast-draining sandy, gravelly, or rocky soil across a pH range of about 6.5-8.5. As a cool-season desert annual it relies on autumn and winter rain, germinating in cool soil and flowering before summer heat. Water needs are low, and established plants tolerate drought and finish their cycle quickly in dry years. Sown in autumn on bare ground in mild-winter areas, it self-sows where conditions suit. The glandular foliage can cause skin irritation during handling and weeding.

Pruning

Requires no pruning as a desert annual. Spent plants are pulled or left to scatter seed once the capsules ripen. Clearing plants before seed set limits self-sowing, and the glandular foliage can irritate skin during handling.