How to Grow Water Hyssop (Bacopa monnieri)

This semi-aquatic perennial plant looks great in hanging baskets

Water Hyssop close up of green leaves and white flowers

michael meijer / Getty Images

Water Hyssop, also known as Bacopa monnieri or herb-of-grace, is a creeping, low-growing perennial herb that is native to wetland environments. This means it lends itself well to ornamental aquariums and ponds and, with its little white flowers, it also looks lovely in hanging baskets.

Given its origins, it does best in moist soils. Fast-growing, Water Hyssop can be invasive if you're not careful about pruning it back regularly. If you live in an area that hosts White Peacock Butterflies, this plant may appeal as it's known to attract the caterpillar of this beautiful species.

Don't opt for Water Hyssop if you love a fragrant garden—its flowers are non-aromatic. Despite its name, this plant isn't related to the Hyssop (which is part of the mint family). Instead, the Water Hyssop is part of the Plantaginaceae (Plantain) family.

Botanical Name Bacopa monnieri
Common Name Water Hyssop, Brahmi, Herb of Grace
Plant Type Perennial herb
Mature Size Up to 12 inches
Sun Exposure Full Sun/Part Sun
Soil Type Moist clay, loam or sand, and in standing water
Soil pH Can grow in a wide range of ph levels but, ideally, between 5 - 7
Bloom Time Late Spring to Early Fall
Flower Color White to light pink flowers and evergreen, succulent leaves
Hardiness Zones 8 to 11
Native Area Found in warm wetlands on most continents
Plating young Water Hyssop in a hanging basked
Water Hyssop is a good plant for a well-watered hanging basket. GarysFRP / Getty Images
Young Water Hyssop just beginning to bloom
Water Hyssop is a creeping herb that has a pretty but unscented flower. ben-bryant / Getty Images
Water Hyssop in a window box with other flowers
Creeping Water Hyssop looks lovely in window boxes and in ornamental aquariums. Vaivirga / Getty Images

How to Grow Water Hyssop

Water Hyssop is a low-growing herb that quickly spreads like a mat across the ground or in ponds. The root system is vast, and you'll need to allow for this when considering where to plant it.

It would help if you also trimmed it back regularly when it's in full growth to prevent it from spreading across any other plants in the area.

Light

This plant does well in full sun or partially shaded areas. It can cope with hot weather conditions, providing you make sure that its generous moisture needs are met.

Positioning your Water Hyssop in a sunnier location will encourage fuller growth. If it's located in an overly shaded area, the leaves will be more spread out, and the plant will have a sparser appearance.

Soil

Water Hyssop isn't too fussy when it comes to soil types providing they're moist. Their capable of growing in acid, alkaline and neutral soils that are sandy, loamy or clay-like.

Water

Water Hyssop is, unsurprisingly, not a drought-resistant plant, and its succulent leaves need a lot of water to thrive.

Temperature and Humidity

Water Hyssop does well in warm and tropical conditions. Humid temperatures are not a problem as this plant needs moisture to thrive. If you frequently experience cold snaps or temperatures that are generally below 60 degrees Fahrenheit, then this won't be the plant to opt for.

Fertilizer

When this herb is planted in the ground or in baskets, half strength, slow-release fertilizer will be enough to encourage rapid and healthy growth.

If your Water Hyssop is in an aquatic setting, you shouldn't use fertilizer unless it's specifically designed for this type of environment. It can encourage the rapid growth of algae.

Propagating Water Hyssop

This fast-growing and long-lived plant is easy to propagate. You can take cuttings any time between late spring and early summer or divide the root for replanting in spring or fall.

Pop the five to ten centimeter cuttings into water and then enclose them in a humidity bag until you notice the roots have grown visibly.

Harvesting

The leaves of Water Hyssop are edible and can be consumed raw or cooked. Although not one of the most popular or flavorsome herbs, it's well known for its medicinal properties. It's recognized as being beneficial for the nervous system.

It's best to harvest the leaves just as the little flowers are starting to bloom in the summer, but they can be picked right through the fall too.

Being Grown in Containers

Water Hyssop needs a deep container to accommodate the sprawling roots. Make sure you select a sealed bottom pot as you want the soil to remain moist. If you're keeping the container indoors, select a well-lit and warm area for best growth. It'll do best in a humid environment, so if the air in your home is dry, the results may not be as impressive.

Growing From Seeds

Generally, propagation rather than seed growth is recommended. The seeds are very small, and successful germination can be hard to achieve.

If you do wish to try growing Water Hyssop from seeds, because it's fast-growing and has a complex root system, in spring, you should plant the seeds at least six inches apart.

The seeds should be sown close to the surface, and ideally in sunny conditions. The soil should be kept moist.

The seedlings are small and delicate, and it's better to let them grow considerably first if you plan to pot them into containers or reposition them.