Soil can be wet because it is compacted, or because of a high water table, where the upper level of the ground water is near the soil surface. Clay soils are wet in winter and baked dry in summer. Unless you install drainage, you will need to work with your soil and choose plants adapted to wet conditions.
Having waterlogged clay soil in your garden can seem like a challenge, but it doesn’t have to stop you from having a beautiful landscape. While heavy, dense clay soil that retains too much moisture may limit your plant choices, there are quite a few options that not only tolerate these conditions, but thrive in them
With the right plant selections, you can have a garden that flourishes in wet and heavy clay soil. Read on for 18 of the best plants for waterlogged clay soil and tips to help them prosper.
Why Choose Plants for Waterlogged Clay Soil
Waterlogged clay soil creates an environment that can be hard for many plants’ roots to grow in. The tiny clay particles compact together when wet, creating poor drainage and air pockets. Roots need some air space between soil particles to receive oxygen. They also require room to spread out and grow.
Plants that naturally grow in soggy areas have roots adapted for these conditions. They can withstand the lack of oxygen and exert the force needed to penetrate the dense soil. Many also have rhizomes or other water-tolerant root structures.
Choosing plants suitable for waterlogged clay soil saves you time and trouble. You avoid having to amend the soil excessively to get it to support plants that prefer drier conditions. Work with your soil’s natural tendencies rather than fighting an uphill battle.
18 Great Plants for Waterlogged Clay Soil
Here are 18 excellent options if you need plants that can handle wet, dense, clay soil.
1. Canna Lily
With its large, tropical-looking leaves and showy flowers in shades like red, orange, and yellow, canna lily (Canna indica) is a beautiful addition to gardens and landscapes. It thrives with consistent moisture and is tolerant of soggy clay soil. Give it full sun to encourage the most prolific blooms.
2. Cardinal Flower
Cardinal flower (Lobelia cardinalis) is aptly named for its vibrant red blooms that attract hummingbirds. It grows along stream banks and pond edges in nature, so it’s no surprise this wildflower tolerates wet feet. Partial shade suits it best where summers are hot.
3. Golden Sedge
Valued as a ground cover, golden sedge (Carex aurea) will brighten up shady spots where water tends to collect. Its slender yellow leaves offer texture without overwhelming smaller plants. This no-fuss grass thrives in heavy clay soil with medium to high moisture.
4. Swamp Milkweed
Clumps of upright foliage and pom-pom shaped flower clusters make swamp milkweed (Asclepias incarnata) a focal point. It provides needed food sources for monarch butterflies and other pollinators. Growing zones 3-8 welcome this moisture-loving milkweed.
5. Water Mint
A garden just isn’t complete without the intoxicating scent of fresh mint. For wet areas with poor drainage, turn to water mint (Mentha aquatica). Watch for its spreading habit and keep it corralled. Its vigorous growth allows for frequent harvests to use in teas, desserts, and more.
6. Asters
Native asters, like New England aster (Symphyotrichum novae-angliae), are well suited to heavy, moist clay soil. Their multitude of daisy-like flowers in shades of purple, pink, and magenta appear in autumn to feed pollinators before winter. Plant them in full sun for optimal flowering.
7. Siberian Bugloss
With pretty blue flower sprays in spring and lush green foliage all season, Siberian bugloss (Brunnera macrophylla) brightens up shady gardens plagued by wet clay soil. The leaves spread wider than the 2-3 foot height for ample ground cover. It tolerates complete saturation.
8. Bistort
Also called snakeweed, bistort (Persicaria bistorta) produces plumes of small pink flowers like cotton candy. The dense root system allows it to handle poor drainage, making it ideal for planting along pond or stream banks. Bistort grows 1-3 feet tall and spreads readily.
9. Spider Lily
You’ll feel like you’re gazing upon an exotic tropical flower when spider lily (Hymenocallis occidentalis) blooms. The white petals extend out like spider legs from the center. This bulb thrives with ample moisture but tolerates drier periods too. Let it flourish in partial sun.
10. Japanese Primrose
Candelabra primrose (Primula japonica) blooms prolifically in shade gardens that never fully dry out. The tiers of flowers come in colors from white to pink to red. Plant it alongside ferns, hostas, and astilbes that enjoy the same growing conditions for a cohesive look.
11. Lobelia
Among the showiest lobelias, cardinal flower (Lobelia cardinalis) stands out with spikes of brilliant crimson blooms that attract hummingbirds. While it appreciates consistent moisture, make sure the soil drains well. Lobelias add charm to partially shaded beds.
12. Obedient Plant
Clumping perennial obedient plant (Physostegia virginiana) produces abundant tubular pink flowers on tall stems above foliage. A member of the mint family, it spreads through underground rhizomes. Give it medium to wet soil and full or part sun. Cut it back midseason to encourage rebloom.
13. Yellow Iris
Add vibrant spring color and vertical height to soggy areas with yellow flag iris (Iris pseudacorus). This moisture loving plant sports flat, bright yellow blooms. The sword-like foliage provides excellent texture contrast to other plants with big leaves and round shapes.
14. Sweet Flag
Graceful arching leaves make sweet flag (Acorus americanus) stand out. This herbaceous plant tolerates completely submerged soils when located in standing water or on the edge of ponds and water features. Use it in place of invasive golden creeping Jenny. Sweet flag grows 1-3 feet tall.
15. Swamp Rose Mallow
Swamp rose mallow (Hibiscus moscheutos) produces hollyhock-like flowers up to a foot across! Available in shades of white, pink, and red, the blossoms demand attention. As a bonus, decorative seed pods follow the flowers. This hibiscus tolerates both wet soil and drier conditions.
16. Thalia
With huge, elegant leaves and unique, cone-shaped blue flower spikes, Thalia (Thalia dealbata) provides exotic appeal to water gardens and pond margins. Also known as powdery thalia, this hardy water lover can grow up to 6 feet tall in just one season! Its size makes a dramatic statement.
17. Pickerel Weed
A favorite of pollinators, pickerel weed (Pontederia cordata) should be planted in full sun to maximize its long-lasting lilac-blue flower spikes. The heart-shaped leaves have appealing shiny texture. While it flourishes in standing water, pickerel weed can also handle merely damp soil.
18. Marsh Marigold
Brighten up boggy areas and stream banks with cheerful yellow marsh marigold (Caltha palustris). This moisture loving perennial blooms in earliest spring, providing a needed food source for emerging pollinators. In summer, dense lush foliage fills in areas where few plants survive.
Growing Tips for Plants in Waterlogged Clay Soil
To help plants thrive in wet clay soil, incorporate generous amounts of compost at planting time. Compost improves drainage while adding nutrients and beneficial microbes. Periodically topdress established plants with a fresh layer of compost or high-quality garden soil to refresh nutrients.
Space plants far enough apart to allow for good air circulation once they mature. Allowing adequate airflow discourages fungal diseases.
Avoid foot traffic and digging around plants when soil is waterlogged. Clay is easily compacted, so limit activities that could increase compaction while soil is wet. Wait until it partially dries to work around plants.
Use 3-4 inches of organic mulch like shredded leaves, evergreen needles, wood chips or compost around plants. This helps retain soil moisture during hot, dry spells and reduces compaction from heavy rain. Replenish as mulch decomposes.
Group plants with similar watering needs together in flower beds. This streamlines your watering and care routine. Focus any soil amendments in just the planting bed instead of entire garden.
Ensure plants receive appropriate sunlight for their needs. Monitor drainage patterns in your landscape and select sun lovers for the driest spots within reach of plant roots. Reserve shady areas for moisture lovers.
With the right plant choices suited to wet clay soil, you can create garden beds that flourish despite challenging soil drainage and density. Pay attention to plants that thrive naturally in swampy areas or along pond edges, as these will likely adapt well to your waterlogged clay soil.
How do I know if I have wet soil?
Soils that are wet all year round are difficult to manage. It is common to have wet soil in winter and dry in summer. This is a characteristic of a clay soil. To have a truly wet soil, it would be wet all year round. Excavate a straight sided pit to about 60cm (2ft) deep. Leave the pit overnight, covered to exclude rain. If water collects in the pit you have high water table. If there is no water, fill the pit with water and leave covered as before for 24 hours. If water remains, drainage is poor.
Further information about the soil texture and structure can be gathered by examining the sides of the pit. Plant roots are mostly within the top 50cm (20in) of the soil surface. Examine the sides of your soil pit, if roots do not penetrate deeply into the soil, or if a hard layer is identified, then deep digging will be needed to loosen the soil to allow drainage. If the darker topsoil rests on a thick layer of impervious clay or rock deep digging won’t help, and raised beds may be necessary.
10 Moisture Loving Perennials That Thrive In Wet Soil Wet Garden Plants
FAQ
How do you fix waterlogged clay soil?
- Improvement number one: Aerate the compacted clay soil. …
- Improvement number two: Take good care of your grass. …
- Improvement number three: Install a drainage system. …
- Identify the cause of the excess water. …
- Clean and clear the area after the flooding.
What grows in clay soil poor drainage?
- Black Eyed Susan (Rudbeckia) – Zone 4-9.
- Daylily (Hemerocallis) – Zone 3-9.
- Echinacea (Echinacea purpurea) – Zone 3-9.
- Phlox (Phlox) – Zone 4-8.
- Sedum (Sedum) – Zone 3-9.
What grows best in waterlogged soil?
- Astilbe (Astilbe simplicifolia) — One of my favorite astilbes is ‘Sprite’ because of its unique airy, shell-pink flowers and dark, bronze-green foliage.
- Canna — Another great plant for growing in standing water.
- Joe-Pye Weed
- Iris
What plant soaks up the most water?
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Cypress trees (Taxodium spp.):These trees, often found in swamps, have roots that can extend above the water surface (cypress knees) to aid in gas exchange and water absorption.
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River birch (Betula nigra):A tree with a high water requirement, often found near water bodies.
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Red maple (Acer rubrum):Another tree that thrives in wet areas and can absorb significant amounts of water.
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Poplar trees (Populus spp.):These trees are known for their rapid growth and high water needs, making them efficient at absorbing moisture.
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Ash trees (Fraxinus spp.):Similar to poplars, ashes are often found in wet areas and have a high water demand.
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Mangroves:Found in coastal areas, mangroves have specialized roots called pneumatophores that help them absorb oxygen and filter water from salty environments.
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Sweetgum (Liquidambar styraciflua):Another tree species that prefers wet conditions and absorbs a lot of water.
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Black Gum (Nyssa sylvatica):Also known as tupelo, these trees are well-suited for wet or boggy areas.
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Rushes (Juncus spp.):These plants are common in wetland areas and have roots that help hold the soil and absorb water, according to Express Water Solutions.
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Cattails (Typha spp.):These wetland plants are highly effective at absorbing water and are often used in drainage projects, according to Express Water Solutions.
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Blue flag iris (Iris versicolor):This iris species thrives in wet areas and can absorb a significant amount of water, according to The Spruce.