New Moon Nurseries


Search by Characteristic

Rudbeckia subtomentosa

Sweet coneflower

FIRST IMPRESSIONS:  Rudbeckia subtomentosa is an upright perennial with pubescent gray-green leaves and sturdy ribbed stems.  In summer plants are crowned by attractive masses of daisy-like flowers.  Blooms are about 3” across with glowing yellow rays and dark brown center cones.  This lovely wildflower thrives in prairie-like settings or average sunny gardens.

HABITAT & HARDINESS:  Plants occur mostly in the Central United States in states bordering the Mississippi River.  The greatest distribution is in Illinois, Missouri, Arkansas and Louisiana.  Scattered populations occur in the eastern United States and in east Texas.

Indigenous plants are found in wet or mesic prairies, Blackland prairies, savannas, thickets, woodland borders and clearings, gravelly seeps and ditch or creek banks.  Plants are usually found in high quality habitats but will sometimes colonize disturbed areas.

Plants are hardy from USDA Zones 4-9.

PLANT DESCRIPTION:  Rudbeckia subtomentosa is a clump forming perennial with upright branched stems.  Plants have short stout rhizomes and deep root to 2’ or more. 

Leaves are toothed and gray-green with downy hairs and long slender petioles.  Basal blades have 3-5 deep lobes but upper leaves are unlobed.

In mid-summer for 4-6 weeks clusters of stalked daisy-like flower heads top the foliage.  The blooms emit a faint sweet anise-like scent.

Heads are 3” across with 10-16 golden-yellow ray florets.  The central hemispherical cone is brownish-purple, flattened on the top and is packed with over 200 small disc florets.

The deep brown cones mature into persistent seed heads.

Plants grow 2-6’ tall with 2-3’ spread.

CULTURAL & MAINTENANCE NEEDS: Rudbeckia subtomentosa is an easily cultivated sun loving plant for moist well drained or average garden soils.  Plants tolerate part sun, heavy clay, sandy loam, heat and humidity.

Established plants can endure some drought and are resistant to deer.

This is a low maintenance wildflower but it may topple if coddled with an abundance of water, fertilizer or shade.

LANDSCAPE USES:  Rudbeckia subtomentosa is a great choice for a Wildlife Garden or a Moist Meadow.  The species is also useful as an Accent, Butterfly Nectar Plant, Butterfly Host Plant or as part of a Grouping or Mass Planting.  Plants provide Showy Blooms, long lasting Cut Flowers and can be used in Cottage Gardens, Deer Resistant Plantings, Low Maintenance Plantings, Perennial Borders, Rain Gardens, Roadsides and Restoration Projects.

COMPANION & UNDERSTUDY PLANTS:   Rudbeckia subtomentosa mingles well with Andropogon gerardi, Asclepias incarnata, Carex bicknellii, Coreopsis tripteris, Echinacea purpurea, Liatris aspera and Monarda fistulosa.

Rudbeckia hirta has similar foliage, flowers and cultural needs.  It can be substituted if a lower growing shorter lived wildflower is acceptable.

TRIVIA:  Flowers are mainly pollinated by bees.  Beneficial wasps, pollinating flies, butterflies, skippers and beetles also visit the flowers.  Caterpillars of silvery checkerspot butterflies and several species of moths feed on the foliage. 

Rudbeckia subtomentosa is a long lived perennial species with lobed basal leaves.  R. hirta and R. triloba are biennials or short lived perennials.  R. hirta has unlobed leaves.  R. triloba has smaller flowers, fewer rays and lobes on both stem and basal leaves. R. fulgida has much shorter height and leaves without lobes.

The specific epithet subtomentosa means “mostly or somewhat hairy”. This species is fairly pubescent but not as much as some other Rudbeckia spp.


Height:

2-6 Feet

Spread:

1-2 Feet

Spacing:

24-36 in

USDA Hardiness Zone:

4-9

Bloom Color:

Yellow

Rudbeckia subtomentosa Characteristics

Exposure

  • Full Sun to Partial Shade

Critter Resistance

  • Deer Resistant

Attracts Wildlife

  • Songbirds
  • Pollinators
  • Butterflies

Soil Moisture Preference

  • Moist to Wet

Attributes

  • Rain Garden
  • Naturalizing
  • Long Blooming
  • Cut Flower
  • Clay Soil
  • Bog

Flowering Months

  • August
  • July
  • October
  • September

Foliage Color

  • Green

Season of Interest (Foliage)

  • Fall
  • Summer
  • Spring

Growth Rate

  • Medium

Juglans nigra Tolerance (Black Walnut)

  • Yes

Salt Tolerance

  • None

Plants that work well with Rudbeckia subtomentosa ''

New England aster New England aster (Aster novae-angliae)
Calico aster Calico aster (Aster lateriflorus 'Lady in Black')
Aromatic aster Aromatic aster (Aster oblongifolius)
Aromatic aster Aromatic aster (Aster oblongifolius 'October Skies')
Purple stemmed aster Purple stemmed aster (Aster puniceus)
Prairie sedge Prairie sedge (Carex bicknellii)
Aromatic aster Aromatic aster (Aster oblongifolius 'Raydons Favorite')
Indian grass Indian grass (Sorghastrum nutans)
Obedient plant Obedient plant (Physostegia virginiana)
Stiff goldenrod Stiff goldenrod (Solidago rigida)

Substitutions for Rudbeckia subtomentosa

Sweet black-eyed Susan Sweet black-eyed Susan (Rudbeckia hirta)