Giant Coneflower

Rudbeckia maxima

Other common name(s):

Great Coneflower, Giant Brown-eyed Susan, Cabbage Coneflower

Family:

Asteraceae (Aster Family)

Plant Ecoregion Distribution Map

East Central Texas Plains, Western Gulf Coastal Plain
Northern Post Oak Savanna, Northern Prairie Outliers
Flatwoods, Floodplains and Low Terraces3, Pleistocene Fluvial Terraces, Red River Bottomlands, Southern Tertiary Uplands, Tertiary Uplands

Plant Characteristics

Growth Form

Herbaceous

Height

3
to
6
ft.

Spread

1
to
2
ft.

Leaf Retention

Deciduous

Lifespan

Perennial

Habitat and Care Requirements

Soil Type(s)

Sand, Moist

Light Requirement

Sun

Water Requirement

High

Native Habitat

Grassland, Wetland or Riparian

Bloom and Attraction

Bloom Color

Yellow

Bloom Season

Spring, Summer

Seasonal Interest

Seeds, Nectar, Pollen

Wildlife Benefit

Butterflies, Birds, Nectar Insects, Bees

Maintenance

May be cut back to the base after blooming or leave seed heads for birds. Plant in mass for best effect in landscapes. Makes good cut flowers. Propagation: seed.

Comments

Blooms March-September. Giant Coneflower has clumps of silvery-blue foliage with a tall, showy flower stalk. The flowers have yellow ray flowers that dangle from cone-shaped brown centers. The fruit is a cypsela: a dry, one-seeded fruit, usually topped by pappus.
Material Treatment Method Collection References
Seed Stratification Stratify for 3 months at 40 degrees. In the spring, Rake seed into a loose topsoil or cover with ¼ to ½ inch of soil or mulch. If possible, supplement with water if fall or spring rains are infrequent and light. The seed requires several days of moisture and should germinate in one to two weeks. The nutlets turn charcoal-gray at maturity, usually 3-4 weeks after the bloom period. Seeds are mature at this time, but they are easier to collect after cones lose their tight compact stucture. Store dry in sealed, refrigerated containers. https://www.wildflower.org/expert/show.php?id=9731
Clump division Division Can be divided every 4 years in spring. chrome-extension://efaidnbmnnnibpcajpcglclefindmkaj/https://txmg.org/hendersonmg/files/2020/06/CONEFLOWER-GIANT.pdf

About the Region

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Salado, the location of our Fall 2025 Symposium, lies at the intersection of two ecoregions: the Edwards Plateau (Limestone Cut Plain) and Blackland Prairie (Northern Blackland Prairie).

The Edwards Plateau area is also called the Hill Country; however, this general term covers a much larger area extending farther north. Spring-fed creeks are found throughout the region; deep limestone canyons, rivers, and lakes (reservoirs) are common. Ashe juniper is perhaps the most common woody species found throughout the region. Additional woody species include various species of oak, with live oak (Quercus fusiformis) being the most common. Sycamores (Platanus occidentalis) and bald cypress (Taxodium distichum) border waterways. This area is well known for its spring wildflower displays, though they may be viewed in spring, late summer, and fall, as well. According to Texas Parks and Wildlife, average annual rainfall in the Edwards Plateau ranges from 15 to 34 inches.

The Blackland Prairie extends from the Red River south to San Antonio, bordered on the west by the Edwards Plateau and the Cross Timbers, and on the east by the Post Oak Savannah. Annual rainfall averages 30 to 40 inches, with higher averages to the east. This region is dominated by prairie species. The most common grass species include little bluestem (Schizachyrium scoparium) and Indian grass (Sorghastrum nutans) in the uplands and switchgrass (Panicum virgatum) in the riparian areas and drainages. Common herbaceous flowering plants include salvias, penstemons, and silphiums. This area has suffered greatly from overgrazing and agricultural use. Few intact areas remain, though many of the plants can be found along county roadsides throughout the region.

Our four host chapters (New Braunfels, Lindheimer, Guadalupe, and the Hill Country chapters) are located in one or both of the ecoregions above. However, the eastern portion of Guadalupe County also falls within the Post Oak Savanna ecoregion. Annual rainfall averages 35 to 45 inches, with higher averages to the east. A wide variety of hardwood trees are found, including several species of oaks, elms, and in the Bastrop area, loblolly pine (Pinus taeda). Grasses and forbs dominate in the open savannas, with most common grass being little bluestem. Ranching, agriculture, and fire suppression have allowed woody species to encroach on the once-open savannas.

Source: Wildflowers of Texas by Michael Eason