Rain gardens: only 20 plants survive both the flood and the drought
A rain garden is not a wet garden. It fills after a storm, drains within a day, and then sits dry until the next one. That is two opposite demands on the same plant — and it is why so many rain-garden plantings fail in their first dry August. USDA's data says only 36 plants in our catalogue tolerate both extremes. Twenty are native and buyable.
Published 11 September 2026 · Understory Guide · USDA PLANTS data, catalogue version 2026-09-11
The mistake most lists make
Search for rain garden plants and you get wetland plants: things that grow in bogs, pond margins and ditches. They will handle the flood. Many of them will not handle the three dry weeks that follow, because a rain garden drains — that is the entire point of building one.
The reason this error is so common is that most plant data has a single moisture field, and a single field cannot express "survives both extremes". USDA publishes two independent tolerance ratings: Anaerobic Tolerance (can it live in saturated, oxygen-starved soil) and Drought Tolerance. A rain garden plant needs a high score on the first and a decent score on the second. Almost nothing does.
- 753 plants tolerate waterlogged ground (anaerobic tolerance medium or high)
- 1,094 tolerate drought (drought tolerance medium or high)
- 36 have high anaerobic tolerance and at least medium drought tolerance
- 31 of those are native · 20 are also routinely available
That collapse — from 753 candidates to 36 — is the finding. It is not a subtle filter. It removes 95% of the plants a wet-soil list would give you.
The twenty
Every one of these is native to North America, routinely available, rated
High by USDA for anaerobic tolerance, and Medium or
High for drought. Sun tolerance varies, so match it to your basin: most
rain gardens sit in the open, but the list includes shade-tolerant options for one built
under a canopy.
Canopy trees
Goodding's willow Salix gooddingiiZone 4+ · 40 ft · full sun · drought medium
MacKenzie's willow Salix prolixaZone 2+ · 45 ft · full sun · drought medium
Understory
hardstem bulrush Schoenoplectus acutusZone 3+ · 9.8 ft · full sun · drought medium
Shrub layer
bog Labrador tea Ledum groenlandicumZone 3+ · 3 ft · part shade · drought medium · ⚠ USDA allelopathic
common buttonbush Cephalanthus occidentalisZone 3+ · 15 ft · shade · drought medium
hobblebush Viburnum lantanoidesZone 3+ · 10 ft · shade · drought medium
narrowleaf willow Salix exiguaZone 3+ · 10 ft · part shade · drought medium
park willow Salix monticolaZone 3+ · 12 ft · full sun · drought medium
redosier dogwood Cornus sericeaZone 3+ · 5 ft · part shade · drought medium
rose spirea Spiraea douglasiiZone 4+ · 7 ft · full sun · drought medium
saw palmetto Serenoa repensZone 7+ · 7 ft · shade · drought high
Herb layer
beardless wildrye Leymus triticoidesZone 2+ · 3 ft · full sun · drought high
blue wildrye Elymus glaucusZone 3+ · 3.3 ft · shade · drought high
meadow barley Hordeum brachyantherumZone 2+ · 2 ft · full sun · drought medium
reed canarygrass Phalaris arundinaceaZone 3+ · 6 ft · full sun · drought medium · ⚠ USDA invasive/noxious status
saltmeadow cordgrass Spartina patensZone 7+ · 3.2 ft · full sun · drought medium
troublesome sedge Carex molestaZone 3+ · 3 ft · full sun · drought medium
Ground cover
buffalograss Bouteloua dactyloidesZone 3+ · 0.5 ft · full sun · drought high
New York fern Thelypteris noveboracensisZone 4+ · 1.5 ft · shade · drought medium
saltgrass Distichlis spicataZone 3+ · 1.1 ft · full sun · drought medium
Two flags worth heeding. Reed canarygrass (Phalaris arundinacea) carries a USDA invasive or noxious status. It is genuinely superb at this job, which is exactly why it escapes and takes over wetlands downstream. We list it because removing it would hide a plant you will be offered; we would not plant it.
Bog Labrador tea (Ledum groenlandicum) is flagged allelopathic — it suppresses plants growing near it. Give it room.
Reading the list for your own basin
Willows dominate the woody end, which will surprise nobody who has seen what grows in a floodplain. Note the range of sizes: Goodding's willow and MacKenzie's willow are 40–45 ft canopy trees and belong nowhere near a suburban basin, while the shrub willows sit at 10–12 ft. Grasses and sedges carry the rest of the list, and those are the layer that actually does the hydraulic work — fibrous roots opening the soil so the basin drains on schedule.
One thing our data cannot tell you: how fast your basin drains. That is a soil-infiltration question, it is site-specific, and no national dataset answers it. Dig a hole, fill it, and time it before you plant anything.
Methodology
Source. USDA PLANTS, quoted, via PlantCharacteristics.
See data & sources.
"Tolerates flooding" = USDA Anaerobic Tolerance of
High. This rates survival in oxygen-starved, saturated soil — the actual
mechanism that kills plants in a wet basin.
"Tolerates drought" = USDA Drought Tolerance of
Medium or High. We deliberately do not use USDA's
Moisture Use field for either claim: it measures how much water a plant
consumes relative to its neighbours, not what it can survive, and the two disagree
often enough to put a swamp species on a drought list.
Limits. USDA rates tolerance nationally, without reference to how long the flooding lasts. A basin that holds water for a week is a different proposition from one that drains in six hours, and no field here distinguishes them. Treat this as a shortlist to check locally, not a planting plan.
Counts computed 11 September 2026, catalogue version 2026-09-11 (2,169 plants).
Related
- All wet-tolerant natives you can buy
- Shade over clay: 264 natives that cope
- Dry shade: 179 plants can take it, 87 you can actually buy
Written and edited by the Understory Guide team. We publish the query behind every number. Corrections: contact us.