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Scutellaria lateriflora

side-flowering skullcap

Lamiaceae North America

Attracts Pollinators

Native to North America

SunPart Shade – Full Shade

WaterHigh

HardinessZones 4–8

Overview

Scutellaria lateriflora, mad-dog skullcap, is a slender perennial of the mint family that grows 12–30 inches (30–75 cm) tall on square, branching stems. The opposite leaves are oval to lance-shaped, 1–3 inches (2.5–7.5 cm) long, with toothed margins and short stalks. Through summer it bears small two-lipped flowers about 0.3 inch (7–8 mm) long, pale blue to violet, lined up along one side of slender racemes that rise from the leaf axils rather than the stem tip, which gives the plant its side-flowering name. Each calyx carries a small ridged cap, the feature that names the skullcaps. It spreads by short rhizomes and self-sown seed into loose colonies in damp ground. The plant grows in wet meadows, marsh edges, streambanks, and moist woodland across much of North America, and it fades quickly if the soil dries out. The thin stems can sprawl without nearby support, and the small flowers are easy to overlook. It has a long record of use in herbal medicine as a calming remedy.

Native Range

Scutellaria lateriflora is native to North America, ranging across southern Canada and most of the United States from the Atlantic coast to the Pacific Northwest. It grows in wet meadows, marshes, swamps, and the moist margins of streams and woodland.

Suggested Uses

Used in rain gardens, pond and stream margins, moist native plantings, and herb gardens. It suits naturalized damp shade and pollinator plantings, though its need for steady moisture makes it less suited to dry borders.

How to Identify

Recognized by square stems, opposite toothed leaves, and one-sided racemes of small blue-violet flowers arising from the leaf axils rather than the stem tips. Each flower calyx bears a small raised ridge or cap on its upper side. The lateral flower arrangement separates it from other skullcaps that flower at the stem ends.

Appearance

Size & Dimensions

Height1' - 2'6"

Width/Spread1' - 1'6"

Colors

Flower Colors

Foliage Colors

Fall Foliage Colors

Bloom Information

Bloom Period

~8 weeks

Summer Fall

Flowering runs through summer into early fall, roughly July through September. The small flowers open a few at a time along each one-sided raceme over several weeks. Ridged seed capsules follow as the flowers drop.

Detailed Descriptions

Flower Description

Pale blue to violet

Foliage Description

Green

Growing Conditions

Sun Requirements

SunPartial Shade SunFull Shade

Requires 2-5 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

loam silt peat

Drainagemoist

Water & Climate

Water Needs

High

Frost Tolerance

hardy

Time to Maturity

2-3 years to full size

Care & Maintenance

Care Guide

Grows in part shade to filtered sun and consistently moist to wet, humus-rich soil at a pH of about 5.5–7.0. Water needs are medium to high, and the plant wilts and declines in dry soil. It is hardy in zones 4–8 and spreads slowly by rhizomes into loose colonies. Rich, damp ground near ponds or rain gardens suits it. Division in spring or fall renews older clumps.

Pruning

Cut the stems to the ground in late fall or early spring as new growth begins. Trimming after flowering can prompt a smaller second flush in moist soil. Removing seed heads limits self-sowing.

✓ Toxicity

Non-toxic