What "Rated for Shade" or "Rated for Clay" Means on a Native Plant List
Three answers, not two
Every county page sorts its natives into three groups for each spot: rated to fit, rated not to, and unrated. A plant is rated to fit clay only if USDA's characteristics record says it tolerates fine-textured soil; it is rated not to if the record says it does not. If USDA has no characteristics record for the plant at all, it is unrated, and it is never quietly counted as a fit.
Most natives have no rating
USDA has published growing characteristics for about 36% of the natives in a typical county. The ratings were compiled mainly for plants used in conservation planting - grasses for erosion control, shrubs and trees for windbreaks and wildlife cover - so common restoration species are well covered and small wildflowers, sedges and rare plants often are not. Coverage varies by state: lowest in Hawaii (5%), Arizona (17%), Texas (19%), California (21%), highest in Alabama (45%), Iowa (44%), North Dakota (41%).
How each spot is judged
- Sun all day: any shade-tolerance rating, since every rated plant can take sun in USDA's scheme.
- Half shade and Under trees: shade tolerance rated medium or high, and high only for deep shade.
- Heavy clay and Sandy, drains fast: USDA's adapted-to-fine-soil and adapted-to-coarse-soil flags.
- Never watered: drought tolerance rated medium or high.
- Stays soggy: tolerance of waterlogged (anaerobic) soil, not whether the plant is a wetland species.
That last one matters. Many plants with a wetland indicator grow along stream banks but will not sit in standing water, so the wetland flag alone is not used to call a plant fit for a soggy spot.
What to do with the unrated plants
An unrated plant may suit your spot perfectly; there is just no USDA record to say so. If the rated list for your spot is short, the unrated count on your county page tells you how much is left to ask about. A state native-plant society, a native nursery or a county extension office can usually say which of those plants handle shade or wet feet, from local experience rather than a national table. The gap is widest in counties such as Honolulu County, Hawaii (5% of 528 natives rated), Kauai County, Hawaii (5% of 459 natives rated), Maui County, Hawaii (5% of 476 natives rated). A short rated list can also mean the county itself is thinly recorded, and a few rated plants carry the native-and-introduced caveat.