Herbs are tender, leafy plants with root systems that are often sensitive to moisture conditions in the substrate. Unlike trees and shrubs, they don’t develop woody stems and may have fewer physical defenses against potential threats. As a result, many of them have chemical adaptations that may make them unpalatable to animals yet highly fragrant and medicinally beneficial to humans.
Some of the most commercially important plants due to their culinary, ornamental, and pharmacological value, herbs tend to favor well-draining substrates. Their fragile roots can easily permeate through porous soils and are unlikely to rot under a consistent watering regimen. There are a handful of species, however, that can tolerate continuously moist to wet conditions. These are more likely to thrive along the borders of water features and in problematic parts of the garden.
While herbs can generally be rooted in jars of water, their productivity is increased once they are transplanted into rich sediments. Matching the right herbs to sediment type and moisture availability is crucial in the cultivation of a healthy herb garden. This list of herbs should help you develop a nuanced selection for the moderately moist to permanently wet parts of your backyard.
1) Mint (Mentha spp.)
More than a dozen species within the Mentha genus are famous for their tolerance of moist to wet substrates in areas where other plants may struggle to grow. These hardy herbs are incredibly useful and versatile in a regularly-moistened garden. In fact, they may be so productive that you’ll find their spread needs to be limited by barriers to control root expansion. For this reason, many horticulturists grow them in dedicated plots or containers.
The most popularly cultivated mints include spearmint (M. spicata), peppermint (Mentha x piperita), corn mint (M. arvensis), and water mint (M. aquatica). These herbs, particularly water mint, require generous amounts of moisture to produce their strongly scented and flavorful leaves. A couple more mint species, specifically pennyroyal (M. pulegium) and hart’s pennyroyal (M. cervina), favor wetland conditions.
In the wild, these aromatic species are typically found close to water features, along which they spread in an indeterminate manner. Outside of their unique native ranges, they tend to compete with less aggressive herbs and may become invasive. A constant source of water significantly increases their reach. Their perennial nature likewise keeps them expanding through the years.
2) Basil (Ocimum basilicum)
Used as a culinary ingredient in many parts of the world, basil is one of the most widely cultivated herbs. Known for the strong flavor of its leaves, it now comes in various hybrids with unique taste and aroma profiles. This economically important herb is practically a home staple as it is frequently sold in pots for indoor growth or as seeds for small to large-scale cultivation.
Basil roots generally permeate through the top 8 – 12 inches (20 – 30 cm) of well-draining soils. This herb is largely anchored by a fleshy and thick taproot, which tends to favor conditions in deep pots. The rate at which it should be watered would thus depend on the extensiveness of its roots and on the physical conditions of the substrate in your pot, container, or plot. Note that, while it does prefer a constant supply of moisture, its deep taproot may suffer in waterlogged conditions. Today, commercial cultivation is often done in soilless media.
Basil is a classic example of an herb that does love water, yet dislikes permanently wet soil. For high productivity rates, it should be grown in well-ventilated and fully sunlit areas with regularly-moistened and well-draining substrates. An enriched media should enhance leaf production and strengthen the flavor of the leaves.
3) Chives (Allium schoenoprasum)
Perhaps one of the easiest and non-fussy herbs to grow in both indoor and outdoor locations, chives are chiefly cultivated for their citrus-flavored leaves. Though it is closely related to garlic, onion, and other bulb-producing crops, its conical bulbs are rarely used for culinary purposes. Its edible blooms, when they are dried and added to fragrant bouquets, are occasional additions to salads.
Seemingly magical in its steadfast production of new leaves, even after being cut to the ground, chives thrive best in well-draining and pH-neutral substrates. For maximum production rates, its root system needs to be exposed to a consistent source of moisture. Waterlogged conditions may compromise the roots of unhealthy plants. For cultivation in indoor locations, growth in a pot or in a jar of nutrient-enriched water (both by a windowsill) should suffice.
In areas with ample ventilation and sun exposure, chives may need to be watered twice a day to ensure that the substrate remains moist. The provision of water early in the morning and late in the afternoon is recommended. Stands that are located outdoors would naturally need more water through summer, which is the peak period for leaf production.
4) Crimson beebalm (Monarda didyma)
A member of the mint family (Lamiaceae), the crimson beebalm is a fragrant herb. Its scent has been likened to that of bergamot orange (C. bergamia), which is famous for its essential oil. This particular beebalm is a perennial species with commercial importance as an ornamental. Its showy blooms, comprised of deep-red petals and bracts, attract hummingbirds and moths.
Species of the Monarda genus generally favor moist conditions. The crimson beebalm is especially unique as a water-loving herb because it naturally produces large clusters along the banks of streams and in wet thickets. Established stands are even able to tolerate occasional flooding. When moisture is scarce, however, they are likely to die back or exhibit stunted growth.
Like its close cousins, the crimson beebalm has medicinal value due to its phytochemical components. In its native range, it has been used as a natural antiseptic and as an herbal treatment for various bacterial infections. While it may no longer make sense to chiefly grow this species for its chemical uses, it would make for an attractive addition to plants in a rain garden or along water features.
5) Garden angelica (Angelica archangelica)
Garden angelica is a biennial herb with medicinal, culinary, and ornamental value. To cultivate this species, it must be grown in an area that receives consistent moisture. In the wild, its stands favor conditions in damp substrates that are located close to natural water sources, like rivers and streams. It will fail to become established in dry soils. Porous and well-aerated sediments should work best.
Although this herb favors damp conditions, its roots may become compromised when they are submerged in standing water. If you do intend to plant it close to water features, make sure that there is no risk of flooding or that there is at least ample drainage to prevent the soil from becoming waterlogged. Also, take note that if it is planted too far away from a constant water source, it will have to be irrigated or watered regularly.
Hardy to cool climates, this northern temperate species is best for USDA hardiness zones 5 – 9. Within just two years of growth, it can reach a full height of about 6 feet (1.8 meters)! Its oil-rich roots are frequently used as a botanical product in the formulation of gin. Due to the presence of aromatic compounds, its oil generates an interesting and distinctively musky scent.
6) Common comfrey (Symphytum officinale)
A member of the forget-me-not family, the common comfrey is a hardy perennial with a history of use in traditional medicine. Herbalists once believed its roots could be an effective treatment for ailments like osteoarthritis and other internal disorders. Currently, research into the herbal use of this species highlights gaps in its safety and its possible toxicity. While it would definitely not be a candidate for a medicinal plant in a home garden, it can be grown as an ornamental herb in moist to wet areas.
The common comfrey naturally thrives in damp substrates, especially those which are located along river banks, ditches, and other naturally-moistened locations. It often grows alongside other water-loving grasses and herbs. Its ease of growth in moist to wet areas has allowed it to thrive and compete with plants in wetlands that are well outside of its native range.
Able to grow up to 3 feet (1 meter) tall, this grassland species is distinguished by its large and lengthy green leaves, its dark-colored roots, and its hairy stems. In late spring to early summer, healthy specimens develop eye-catching inflorescences with colorful, bell-shaped blooms. These attract insects with adaptations for collecting their hard-to-reach nectar.
7) Parsley (Petroselinum crispum)
Widely farmed as a culinary herb, parsley is a leafy biennial with several botanical cultivars. Some types are grown for their flavorful leaves, whereas others are chiefly harvested for their thick, carrot-like roots. Generally, all types favor regularly moistened and well-draining substrates in sunny locations. If the soil is allowed to dry out, the leaves may undergo “bolting” and develop an unfavorable taste profile.
The parsley taproot becomes enlarged as it acts as a site for nutrient storage through winter. In tropical to subtropical areas, it is usually cultivated as an annual herb. Once the plant has reached its mature stage of growth and has developed its own seeds, it may begin to die back. In areas with temperate climates, the full life cycle takes about two years; the floral stalk begins to develop only after the first winter.
Parsley is known for drawing many pollinators to the herb garden. Its umbels of yellow to green blooms attract butterflies, bees, and other nectar-loving insects. Its seeds attract small birds, such as goldfinches. If you find that your herb garden needs more diversity, parsley may be a perfect choice!
8) Chervil (Anthriscus cerefolium)
Very closely related to parsley, with which it is often confused, this lesser-known, annual herb is now naturalized in many parts of Europe and North America. It is a must-have herb in the arsenal of a French chef as its pungent aroma and strong flavor add just the right amount of complexity to many soups and salads.
To produce its lengthy taproot and its tripinnate leaves, chervil requires a moist, well-draining substrate. It favors cool conditions because a hot climate can lead to bolting and may facilitate the reallocation of nutrients for rapid seed production. Light shade in a part of the garden that naturally receives moisture would be best for chervil cultivation. In shaded gardens, it can thus be used as an alternative to herbs that favor more sunny locations.
Organically-enriched soil is another requirement for chervil growth. The regular application of a high-nitrogen fertilizer should lead to the production of more leaves. These should be harvested regularly as pruning can help prevent bolting and stimulate the growth of better-tasting leaves. Note that older plants are more likely to have bitter leaves.
9) Marsh mallow (Althaea officinalis)
Marsh mallow roots, which were traditionally used to produce what we commonly know as marshmallow confectionary treats, form just one of this herb’s edible organ systems. The leaves and flowers can also be cooked and pickled to create an interesting dessert. Boiling any of the plant’s parts in water creates a traditional, egg white substitute with pharmacological properties.
A conversation starter, this perennial can be cultivated as an ornamental and culinary herb in moist parts of the garden. In the wild, it usually grows in areas with marshy conditions, particularly those which are located close to the coast. It also grows along the margins of swamps and streams, in wetlands with brackish water conditions, and in ecologically disturbed ditches.
Healthy marsh mallow plants can measure as tall as 6.5 feet (2 meters). They are set apart by their multi-lobed, serrated, and thick leaves. From August to September they bear delicate, lilac to pink-toned flowers with deeply-colored anthers. When these are pollinated, they give rise to flattened, spherical fruits.
10) Lemongrass (Cymbopogon citratus)
Though lemongrass is a tropical plant, it can be cultivated in subtropical to temperate regions with mild climate conditions. It is a remarkably hardy herb that can grow in almost any type of substrate (with the exception of clay) as long as its roots are provided with ample moisture. A member of the grass family, it can be used as an ornamental plant to add texture and color to potentially problematic parts of the garden.
In the wild, lemongrass favors humid and brightly lit locations with access to a consistent source of moisture. It produces dense clumps which gradually spread to fill out a bed of tilled soil or a dedicated container. In just a single growing period, its leaves can rapidly lengthen and arch over so that the entire plant measures as much as 5 feet (1.5 meters) tall!
Garden zones with high humidity and moisture rates may attract all sorts of pests. This remarkably useful grass can be grown in these areas to ward off unwanted insects, particularly mosquitoes. It naturally produces an essential oil with a fragrance that acts as an effective repellent. You may thus want to grow this water-loving grass close to your porch or around a water garden.
