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Silphium perfoliatum var. connatum

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Plant types and subtypes: Perennials

Light Requirements: sun, part-sun

Water Use: medium

Soil Moisture: moist

Soil Description: rich, loam, clay

Height: 6'-10'

Bloom Time: June, July, August

Bloom Color: yellow

Leaf Color: green

Hardiness Zone: 6, 7

Additional Tags: attracts birds, attracts butterflies, attracts hummingbirds, clumping, colonizing, cottage garden plant, naturalizing

Flower of Silphium perfoliatum var. connatum (cup plant)
  • Flower of Silphium perfoliatum var. connatum (cup plant)
  • Flower of Silphium perfoliatum var. connatum (cup plant)
  • Flower of Silphium perfoliatum var. connatum (cup plant)

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Description

Silphium perfoliatum var. connatum

Also known as:

cup plant

,

New River cup plant

Scientific Synonyms:

Silphium connatum, Silphium scabrum

Description

The cup plant is an awe-inspiring, majestic plant. Reaching heights of up to 10 feet, it will form clumps up to 6 feet wide, topped with large 2" to 4" yellow flowers resembling sunflowers . Large triangular, downy leaves join at their bases to form water-holding cups around the stout, square, purplish, hairy stems. Birds will actually bathe in the cups after a rain. A beautiful specimen!

Cultivation

Enjoying full sun to light shade, Silphium perfoliatum var. connatum does best in rich, moist, loamy soil. It is very easy to grow and requires very little care. Due to its sheer size, it will create a visual focal point wherever it is placed. Its ability to self seed can make it somewhat invasive. It blooms from June through August. Zones 6-7

Propagation

Plants self propagates readily by seed. Mature clumps are deep rooted and may be difficult to divide, however, young offshoots can be removed and transplanted.

Additional Notes

Although Silphium perfolatum has an extensive native range from the Midwest to the entire East-coast, its variety connatum is native only to VA, WV, MD, NC and can be identified by its hairy stems and sessile leaves. The genus got its common name rosinweed, because of the large amounts of resin exuded from injured parts of the plant.

Native Range & Classification

Recorded County Distribution: USDA data

Native Range:
AL, AR, CT, GA, IA, IL, IN, KS, KY, LA, MA, MD, ME, MI, MN, MO, MS, NC, ND, NE, NJ, NY, OH, OK, PA, SD, TN, VA, VT, WI, WV

USDA Endangered Status:

  • Threatened: MI

Classification

Kingdom Plantae Plants
Subkingdom Tracheobionta Vascular plants
Superdivision Spermatophyta Seed plants
Division Magnoliophyta Flowering plants
Class Magnoliopsida Dicotyledons
Subclass Asteridae
Order Asterales
Family Asteraceae Aster family
Genus Silphium rosinweed
Species Silphium perfoliatum var. connatum cup plant