ballhead waterleaf
Hydrophyllum capitatum · Hydrophyllaceae
ballhead waterleaf (Hydrophyllum capitatum) is a perennial herbaceous plant in the Hydrophyllaceae family. It is native to North America. USDA records it as hardy in zone 4 and warmer, down to about -28°F.
At a glance
| Type | forb-herb USDA |
|---|---|
| Lifecycle | perennial USDA |
| Native status | native USDA |
| Mature height | 1 ft USDA |
| Light | shade USDA |
| Water need | high USDA |
| Growth rate | rapid USDA |
| Soil pH | 6.4–7.8 USDA |
| Bloom | March–April USDA |
| Flower color | Purple USDA |
| Hardiness zones | 4 and warmer USDA |
| Guild layer | ground-cover Derived |
| Nursery availability | Contracting Only USDA |
USDA quoted from the USDA PLANTS database · Derived computed by a fixed rule from those columns. No value on this page is estimated.
Growing conditions
It tolerates full shade. USDA rates it as having needs consistently moist ground. Its drought tolerance is rated low. It handles periodically wet ground (USDA rates its anaerobic tolerance medium). It is recorded on soils from pH 6.4 to 7.8 — a broad range that spans acidic through mildly alkaline ground. Its cold limit is zone 4.
Size and growth
At maturity it reaches about 1 ft, making it a low, mat-forming plant. It grows quickly.
Bloom period
USDA records a bloom period of March through April. Flowers are purple.
A flowering date, not a pollinator rating.
Foliage, flower and season
Summer foliage is green, medium in texture. Its flowers are conspicuous. Its active growth period is spring. USDA rates its lifespan as moderate.
What the site needs to provide
USDA records it across sites receiving 16 to 30 inches of annual precipitation. It needs at least 110 frost-free days to finish its season. It roots to at least 10 inches. Fertility requirement: medium.
Propagating it
Seed is the only propagation method USDA lists. Division and cuttings are not listed as options. USDA records no cold-stratification requirement, so seed should germinate without a chilling period. Its seed spreads at a slow rate. It does not spread vegetatively, so it will stay where you put it.
Resilience and wildlife
Browsing animals rate it barely palatable — the sourced basis for calling it deer-resistant. Its fire tolerance is rated low. Its growth form is recorded as single crown.
Role in a guild
Ground cover. In a layered planting this is the lowest layer — it shades soil, holds moisture, and suppresses weeds. The layer is derived by a fixed rule from growth habit and mature height.
Tags
Related plants
Others in Hydrophyllum
- western waterleaf Hydrophyllum occidentale
Similar role and hardiness
- thrift seapink Armeria maritima
- alpine aster Aster alpinus
- Rocky Mountain iris Iris missouriensis
- Japanese pachysandra Pachysandra terminalis
- longbeak buttercup Ranunculus longirostris
Where this data comes from
Every value on this page comes from the USDA PLANTS database record for symbol HYCA4, or is computed from those values by a fixed rule. Nothing here is estimated or model-generated. Where USDA publishes no value, this page omits the claim rather than filling the gap.
- Quoted from USDA PLANTS: active growth period, Bloom, Bloom end, browse palatability, cold stratification, Drought tolerance, fall conspicuous, fertility requirement, fire tolerance, Flower color, flower conspicuous, foliage color, foliage porosity winter, foliage texture, frost free days min, fruit conspicuous, growth form, Growth rate, Hardiness zones, Lifecycle, lifespan, Light, Mature height, Minimum temperature, Native status, Nitrogen fixation, Nursery availability, precipitation max in, precipitation min in, propagation, resprout ability, root depth in, seed spread rate, Soil pH, Soil pH (upper), Tolerance of wet soil, Toxicity, Type, vegetative spread rate, Water need.
- Derived by a fixed rule from those columns: Guild layer.
Read our full data sources and methodology.
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