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bigflower agoseris

Agoseris grandiflora · Asteraceae

bigflower agoseris (Agoseris grandiflora)
Photo: Anthony Valois and the National Park Service · Public domain · via Wikimedia Commons

bigflower agoseris (Agoseris grandiflora) is a perennial herbaceous plant in the Asteraceae family. It is native to North America. USDA records it as hardy in zone 5 and warmer, down to about -13°F.

At a glance

Typeforb-herb USDA
Lifecycleperennial USDA
Native statusnative USDA
Mature height1.8 ft USDA
Lightfull-sun USDA
Water needmedium USDA
Growth ratemoderate USDA
Soil pH5.8–7.3 USDA
BloomMarch–May USDA
Flower colorYellow USDA
Hardiness zones5 and warmer USDA
Guild layerherb-layer 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 moderate water needs. Its drought tolerance is rated medium. It is recorded on soils from pH 5.8 to 7.3 — a broad range that spans acidic through mildly alkaline ground. Its cold limit is zone 5.

Size and growth

At maturity it reaches about 1.8 ft, making it about knee height. It grows at a moderate rate.

Bloom period

USDA records a bloom period of March through May. Flowers are yellow.

A flowering date, not a pollinator rating.

Foliage, flower and season

Summer foliage is green, coarse in texture. Its flowers are conspicuous. Its active growth period is spring. USDA rates its lifespan as short, so plan on replacing or resowing it rather than treating it as permanent structure.

What the site needs to provide

USDA records it across sites receiving 12 to 20 inches of annual precipitation. The low end of that band is genuinely arid, so it has a wide tolerance for dry country. It needs at least 120 frost-free days to finish its season. It roots to at least 8 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 moderate 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 high. Its growth form is recorded as single crown.

Role in a guild

Herb layer. In a layered planting this is the herbaceous middle — perennials and grasses that fill the space between ground cover and shrubs. The layer is derived by a fixed rule from growth habit and mature height.

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Tags

deciduousdrought-tolerantclay-tolerantsandy-soildeer-resistantnativefull-sun

Related plants

Others in Agoseris

Similar role and hardiness

Where this data comes from

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