List of the Best Plants, Trees & Shrubs that Soak Up & Absorb LOTS of Water
Some plants have the wondrous capacity to take up considerable amounts of water. Unlike moisture-sensitive species, these are usually able to tolerate a wide variety of conditions. Horticulture specialists and landscapers value them for their ease of growth and transformative qualities as they can turn marsh-like areas into ecologically stable woodlands.
If your garden is located in an area that experiences frequent flooding, such as a sunken spot or the base of a hill, you will have to be strategic and selective about your plants. Of course, you don’t want your yard to quickly turn into a complete bog. Consider creating a rain garden with water-absorbent plants to reduce water run-off and reinforce your substrate. Do keep in mind, however, that you will have to pinpoint the cause and evaluate the severity of poor drainage in order to create an effective rain garden.
Water-absorbent plants may have to be aided by a slope or drainage pipe if they are located right at the water table. Moreover, their soil should be supplemented with organic material and tilled to create channels for water escape. Keep in mind that, though they absorb lots of water, they may also be harmed by prolonged exposure to waterlogged soil. There should be a recovery period between flooding events.
Trees are normally the masters of water absorption, but shrubs and ornamental herbs can play an important role too. The species listed below often act as water filters and can even help keep our freshwater supply clean, as well as providing shade and attracting wildlife.
1) Atlantic white cedar (Chamaecyparis thyoides)
The Atlantic white cedar is a wetland tree that favors moist soil throughout its growth periods. It is highly adapted to conditions where water has obliterated all air pockets in the soil. It has developed a special adaptation to prevent its entire base from being submerged throughout the year. The tree grows on mounds, or hummocks, that elevate its trunk. Water accumulates in depressed pools that surround the mound.
A white cedar tree can last for centuries, withstanding large fluctuations in moisture availability. It tends to dominate the swamps and bogs in which it is found. This species is an essential water purifier, regulating the distribution of nutrients in both riverine and palustrine systems. Interestingly, it tends to have a fairly shallow root system with strong lateral roots in soils that are permanently waterlogged. Highly aerated soils can encourage its roots to penetrate deeper into the ground.
2) Black gum (Nyssa sylvatica)
Also referred to as black tupelo or sour gum, the black gum tree is a slow-growing deciduous species that can reach a height of 30 – 50 feet (9 – 15 meters) at maturity. It is an attractive tree that is famous for its brilliant fall foliage. Sometimes grown as an ornamental, its best features are brought out by cultivation in moist, slightly acidic, well-draining soil. Its tolerance for wet soil makes it a frequent candidate for the lowland areas of gardens.
Black gum trees fare well when grown individually, but a cluster can provide spectators with a truly stunning view. This tree’s glossy leaves are dark green in spring and summer, but they gradually become an assortment of reds, with yellow, purple, and orange undertones as temperatures begin to drop. Foliage color varies depending on the cultivar.
This species is significantly valuable to wetland wildlife. Its flowers are a vital source of nectar for bees, and its fruits provide birds and deer with beneficial nutrients.
3) Red maple (Acer rubrum)
Red maple is a rapidly-growing, highly abundant deciduous tree. It is best known for its stunning display of red leaves in the fall. Its tiny red flowers are quite showy as well, though they only begin to appear once the tree is at least 8 years old. Red maples are exceptional trees that can grow to an average height of 90 – 120 feet! Their mature trunks remain relatively free of branches, giving this species a distinct crown that creates abundant shade underneath.
Tolerant of a wide variety of soil conditions, red maple trees can be prolific water absorbers in several habitat types. It grows best in moist, slightly acidic soil, however, and is partial to mineral-rich substrates which are vital for seed germination. A single, mature red maple can absorb at least 5 gallons of water each week. It will not need additional watering sessions as long as at least an inch of rainfall occurs on a weekly basis. Mature trees are able to tolerate floods without becoming significantly damaged.
4) River birch (Betula nigra)
The graceful river birch is a bushy tree that is known for having peeling bark as the tree matures. Young trees initially have smooth salmon-colored bark. This eventually flakes off, giving the tree a highly textured appearance that is especially noticeable during winter. When in bloom, this monoecious species produces small catkins that occur in clusters just at the tips of its twigs.
With an average lifespan of 50 – 70 years, river birch is quite fast-growing and can reach a maximum height of 80 feet (24 meters). In the wild, it grows in humid areas, such as swamps and floodplains. It is also referred to as water birch because its root system can tolerate a stream bank or semi-aquatic placement. If your garden has poor drainage, you’ll find that this tree will relish in the persistent moisture. In USDA zones 5 – 9, it is frequently used as a pond edge tree.
5) French rose (Rosa gallica)
Rosa gallica is an attractive shrub that has received the RHS Award of Garden Merit. It is the parent species of many tea rose hybrids, which produce excellent fragrances. This shrub grows to a maximum height of 5 feet (1.5 meters) and can spread to 4 feet (1.2 meters) wide at full maturity. Each summer, its fairly ordinary foliage is masked by a profusion of vivid, deep pink blooms. These develop into rose hips, which attract many birds during winter.
French rose shrubs can tolerate being reared in poor soils and hardly require maintenance, apart from regular plant inspection and pruning. It is great for organically rich rain gardens as it thrives best in consistently moist soil. It does require proper drainage, so you must ensure that its roots don’t sit in standing water for too long. It is also tolerant of shade, though it should be provided with full sun exposure if possible.
6) Bigleaf hydrangea (Hydrangea macrophylla)
Tufts of color, large leaves, and fantastic height – these combined phrases perfectly describe this hard-to-miss shrub. One of the most interesting things about this plant is its capacity to develop flowers that change in color depending on soil alkalinity or acidity. When soil pH is quite high, the floral tufts become more intensely pink. In contrast, an acidic pH alters floral pigmentation, causing the flowers to become a soft shade of light blue.
There are two main hydrangea cultivars: mophead hydrangea and lacecap hydrangea. The former is distinguished by large flower heads with sterile blooms. The latter produces fertile blooms, but their flowers tend to fade in color quickly. Both cultivars are able to tolerate being cultivated in moist soil, but must be exposed to full sun. In cases where soil moisture is reduced, big-leaf hydrangea can be reared in partial shade. This species is great as an accent plant or for use as a hedge. As a bonus, the flowers can be harvested each year and brought indoors for some color.
7) Red elderberry (Sambucus racemosa)
The red elderberry is a tree-like shrub that thrives in riparian forests, woodlands, cliffs, and ravines. It is a popular member of the Honeysuckle (Caprifoliaceae) family. This fast-growing perennial can grow to a height of 12 feet (3.6 meters) and is a popular addition to landscaped gardens, not only for its height but because of its showy features. In spring, mature plants produce soft pink flower buds that eventually open to reveal white or cream-colored petals.
The fruits of this species are small, just ¼ inch in diameter, but they attract many birds. The shrub itself is highly valuable to wildlife as the foliage, buds, and bark are nutritious. Due to its heavy water requirements, red elderberry grows best in moist soil and is an attractive addition to a rain garden. If you’re looking for a cultivar with eye-catching foliage, opt for ‘Sutherland Gold’. Wet conditions are perfect for this variety.
8) Common winterberry (Ilex verticillata)
A deciduous holly with great tolerance for poor drainage, the common winterberry is a low-maintenance shrub that favors moist soil. It can successfully be cultivated in rain gardens, around ponds and fountains, and in swampy areas with acidic soil. It is fairly resistant to pests and diseases and can thrive under full or partial sun exposure. As a wetland shrub, common winterberry is able to tolerate fairly high humidity. Avoid planting this shrub in a dry or sandy area as frequent rainfall or irrigation is needed to keep its root systems happily moist.
When mature, a common winterberry shrub can be as tall as 8 feet (2.5 meters) and spread to a similar width. It produces glossy green leaves with a serrated margin. The leaves normally don’t produce attractive fall colors, but they may occasionally turn maroon. In late spring, white flowers can begin to appear along the plant’s leaf axils, but they are largely negligible.
The bright red berries are the star of the show and can persist into the cold months! These are a great food source for birds, but they can be harmful if ingested by people and pets. Of course, the berries of this holly species can be great fun during the holidays as they are an attractive addition to wreaths and flower arrangements.
9) Japanese iris (Iris ensata)
Commonly used to add dimension and color to ornamental ponds, the Japanese iris is an elegant, water-loving perennial with eye-catching features. It grows vigorously and produces dense clumps of sword-shaped green leaves arising from underground rhizomes. In summer, the beauty of this species reaches its peak as its vibrant blue-violet flowers come into being. The anthocyanin-rich petals are delicate, colorful, and irresistible to many pollinators, including bumblebees.
This species has high demands for moisture all year round. It should only be planted in areas that receive adequate rainfall or along the borders of water features. Prolonged exposure to standing water may be detrimental to this plant’s survival, however, as its roots do require oxygen. Hardy to USDA zones 4 – 9, Japanese iris prefers moderate ambient temperatures and humidity levels.
Japanese iris can easily be propagated to cover a large chunk of your rain garden. It is best planted with the use of rhizome divisions that are collected in the fall. Bury these in soil once temperatures begin to rise in spring and situate them a few feet away from one another to give room for plant spread. In due time, you’ll have a dazzling display of irises that will bloom in gratitude for the consistent moisture!
10) Swamp hibiscus (Hibiscus moscheutos)
The layman’s terms for Hibiscus moscheutos are rose mallow and swamp hibiscus. These common names are more than fitting as they describe the plant’s flowers and its favored habitat. Large pink flowers that look impossibly soft and delicate come into bloom each summer. Their features are exactly like those of near relatives. Each has 5 petals and a deep-colored center, from which a lengthy yellow stamen extends. Ptilothrix and Bombus bees are just some of the swamp hibiscus’ many pollinators.
This wetland species is quite hardy as it can tolerate both cold and warm temperatures. It produces deep-growing and extensive root systems that favor consistently moist soil. The moisture, coupled with air circulation if each shoot is spaced apart, helps the plant cope with the potentially intense summer heat in southeastern US states. Hardy to USDA zones 5 – 9, this species is perfect for use in rain gardens that are exposed to moderate temperature fluctuations.
11) Swamp milkweed (Asclepias incarnata)
Swamp milkweed is another perfect plant for rain gardens. This flowering perennial is capable of absorbing considerable amounts of water. Its root systems are able to thrive in wet to moderately moist substrates. It favors slightly acidic soil and can tolerate poor drainage, seasonal flooding, and even packed clay. Furthermore, its roots are adapted to low-oxygen conditions. In the wild, it is often found growing along the edges of lakes and ponds, in low-lying areas, and in ditches.
The blooms of this plant are irresistible to monarch butterflies, which tend to lay their eggs on the milkweed leaves. Once hatched, the larvae then feed on the foliage. Though safe for the caterpillars, this entire plant is slightly toxic in its raw form and may irritate both the digestive and nervous systems if ingested. If you’d like your rain garden to be fairly deer resistant, you should consider cultivating this species. Do be ready to deal with the occasional appearance of aphids, however, as they favor the milky sap.