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disk waterhyssop

Bacopa rotundifolia · Scrophulariaceae

disk waterhyssop (Bacopa rotundifolia)
Photo: (c) Daniel J. Layton, some rights reserved (CC BY) · CC BY · via iNaturalist

disk waterhyssop (Bacopa rotundifolia) is a perennial herbaceous plant in the Scrophulariaceae family. It is native to North America. USDA records it as hardy in zone 3 and warmer, down to about -33°F.

At a glance

Typeforb-herb USDA
Lifecycleperennial USDA
Native statusnative USDA
Mature height0.1 ft USDA
Lightfull-sun USDA
Water needhigh USDA
Growth rateslow USDA
Soil pH5.4–7.8 USDA
BloomSeptember–November USDA
Flower colorWhite USDA
Hardiness zones3 and warmer USDA
Guild layerground-cover Derived
Nursery availabilityNo Known Source 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 needs full sun. USDA rates it as having needs consistently moist ground. Its drought tolerance is rated none — it needs reliable moisture. It tolerates saturated, poorly drained ground well (USDA rates its anaerobic tolerance high). It is recorded on soils from pH 5.4 to 7.8 — a broad range that spans acidic through mildly alkaline ground. Its cold limit is zone 3.

Size and growth

At maturity it reaches about 0.1 ft, making it a low, mat-forming plant. It grows slowly.

Bloom period

USDA records a bloom period of September through November. Flowers are white.

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, summer, fall. USDA rates its lifespan as moderate.

What the site needs to provide

USDA records it across sites receiving 24 to 65 inches of annual precipitation. It needs at least 120 frost-free days to finish its season. It roots to at least 0 inches. Fertility requirement: low — no feeding needed on ordinary garden soil.

Propagating it

Propagate it from seed, bare root and container stock. USDA records no cold-stratification requirement, so seed should germinate without a chilling period. Its seed spreads at a slow rate. It spreads vegetatively at a moderate rate.

Resilience and wildlife

Its fire tolerance is rated none. Its growth form is recorded as stoloniferous.

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.

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Tags

deciduouswet-tolerantclay-tolerantspreadingnativefull-sunslow-growingground-cover

Related plants

Similar role and hardiness

Where this data comes from

Every value on this page comes from the USDA PLANTS database record for symbol BARO, 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.

Read our full data sources and methodology.

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