Gratiola spp.

hedge hyssop

Plantaginaceae

Worldwide (temperate and subtropical)

Attracts Pollinators Container Friendly

Native to North America

SunFull Sun – Part Shade

WaterHigh

HardinessZones 5–9

Overview

Gratiola spp. is a genus of about 30 species of small annual and perennial herbs in the plantain family (Plantaginaceae), found in wet ground across temperate and warm regions worldwide. Plants are low and often creeping, generally 4–24 in (10–60 cm) tall, with soft, square or rounded stems that root at the lower nodes. The opposite leaves are stalkless, 0.4–1.6 in (1–4 cm) long, narrow to oval, and sometimes toothed. Tubular, two-lipped flowers 0.3–0.8 in (8–20 mm) long are carried singly in the leaf axils on slender stalks, white to cream, often flushed pink or yellow in the throat. The fruit is a small rounded capsule holding many tiny seeds. Plants grow in marshes, stream banks, pond margins, ditches, and seasonally flooded ground, and some, such as G. officinalis, contain cardiac glycosides that are toxic to people and livestock. A few species behave as weeds of rice fields and irrigated land. The common name hedge hyssop refers to the historical medicinal use of G. officinalis.

Native Range

Found across temperate and subtropical regions worldwide, including the Americas, Europe, Asia, Africa, and Australia, with the greatest number of species in the Americas. Plants grow in marshes, pond and stream margins, ditches, and other seasonally wet ground.

Suggested Uses

Grown at the margins of ponds, bog gardens, and rain gardens, where the creeping habit knits wet soil together. Lower species form a low cover in consistently moist ground. Several are kept as aquarium and paludarium plants.

How to Identify

Recognised as a low, soft herb of wet ground, with opposite stalkless leaves and slender, tubular two-lipped flowers borne singly in the leaf axils. The white to cream flowers, often tinged yellow in the throat, and small rounded seed capsules help separate it from similar wetland herbs.

Appearance

Size & Dimensions

Height4" - 2'

Width/Spread6" - 1'6"

Colors

Flower Colors

Foliage Colors

Fall Foliage Colors

Bloom Information

Bloom Period

~14 weeks

Spring Summer

Flowering occurs mainly from late spring through summer, varying with climate and water levels, with flowers opening singly in the leaf axils over a long period. In warm regions some species flower for much of the year wherever moisture persists. Capsules ripen quickly and scatter many tiny seeds.

Detailed Descriptions

Flower Description

White to cream, tinged yellow or pink

Foliage Description

Green

Growing Conditions

Sun Requirements

SunFull Sun SunPartial Shade

Requires 4-8 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 - 7.5(Neutral)

357912

Soil Types

loam clay silt

Drainagewet

Water & Climate

Water Needs

High

Time to Maturity

1 year

Care & Maintenance

Care Guide

Plants grow in full sun to part shade in constantly moist to wet soils, and several thrive in shallow water at pond and bog margins. They tolerate a range of soil types but require ground that never fully dries out. Moisture demand is high, and plants collapse under drought. Perennial species spread by creeping, rooting stems, while annuals rely on self-sown seed. Some species, including G. officinalis, contain toxic cardiac glycosides in all parts. In warm climates a few behave as persistent weeds of wet ground.

Pruning

No formal pruning is needed. Perennial species can be cut or pulled back to control their spread in ponds and bog gardens, and old growth tidied at the end of the season. Annual species are left to set seed.

Pruning Schedule

fall