Cup Plant

Growing Conditions

Growing Zones

Thrives in USDA Zones 3 - 9

Companion Planting

When to Plant

• Transplant

  Transplant young potted plants in spring into fertile, moist soil

• Direct Sow

  Direct sow seed in autumn into prepared moist soil; cold stratification improves germination

• Harvest

  Leave dried seed heads through winter; birds feed heavily on the seeds from autumn through spring

Organic Growing Tips

• Leave all seed heads through winter; cup plant produces large, flat seeds that are one of the most important food sources for goldfinches in the late-season garden.

• The water-filled cups in the perfoliate leaves are used by birds to drink and bathe; this is a valuable wildlife feature, not a problem.

• Cut back to 6 inches in early spring before new growth emerges; the previous year's large woody stalks can be left for overwintering insects if desired.

• Cup plant spreads by rhizome in rich, moist soil; in smaller gardens limit spreading by removing outer rosettes each spring.

• No fertilization needed; cup plant thrives in fertile garden soil without additional inputs.

Common Pests

• Aphids (minor)
• Powdery Mildew (in dry conditions)
• Leaf Miners (minor)

Taxonomy

Kingdom

Plantae

Family

Aster family (Asteraceae)

Genus

Silphium

Species

perfoliatum

Natural History

Silphium perfoliatum, cup plant, is a large, robust native perennial of the aster family (Asteraceae) native to moist prairies, floodplain margins, and disturbed fertile ground across the central and eastern United States and adjacent Canada. It belongs to the genus Silphium, a North American genus of about 20 species that includes other notable prairie perennials such as prairie dock (S. terebinthinaceum) and compass plant (S. laciniatum). The cup plant's most distinctive feature is the pair of opposite stem leaves fused around the stem to form a cuplike basin - the species name perfoliatum (Latin: through the leaf) refers to the stem appearing to grow through the leaf base. These cups catch and hold rainwater for extended periods after rainfall and have been observed to serve as water sources for birds in hot summer weather, and as larval habitat for numerous insects. Cup plant is one of the most prolific seed producers in the prairie perennial community, and the large, flat seeds are heavily consumed by goldfinches, chickadees, and other seed-eating birds from autumn through winter. Cup plant has a long history of use by Indigenous peoples of the central prairies: the resinous roots were chewed for gum, the rosin was used as incense, and various preparations were employed medicinally. Like other Silphium species, it has a characteristic pine-like scent from its aromatic resin.

Traditional Use

Cup plant was used by several Indigenous peoples of the central prairies primarily for its aromatic resin, which was chewed as gum, used ceremonially, and applied in some medicinal preparations. The Silphium genus has a broader traditional use history in the prairie region as a source of fragrant resin and medicine for respiratory and rheumatic complaints.

• Ojibwe (Anishinaabe) people - Roots and resin

  Ojibwe ethnobotanical records document the use of cup plant resin as a chewing gum and as a fumigant. The aromatic root resin was burned as incense in ceremonial contexts. Root preparations were used for respiratory complaints and for general pain. The Silphium species were an important plant group in Ojibwe material culture.

• Various Great Lakes Indigenous peoples - Roots and resin

  Ethnobotanical records from Great Lakes region peoples document the use of the resinous roots of cup plant and related Silphium species for chewing gum, ceremonial smoke, and as a medicine for rheumatism and respiratory ailments. The fragrant resin was also used in horse care in some 19th century records.

Cup plant resin is aromatic and contains terpenoid compounds but is not a significant human health risk in garden contexts. Chewing large quantities of the resinous root is not recommended. The plant is safe to grow and handle in the garden.

This information is provided for historical and educational purposes only and is not medical advice. Always consult a qualified healthcare professional before making decisions related to your health.

Morphology (Plant Structure & Identification)

• Root System

  Deep, stout taproot with spreading rhizomes; root system can penetrate several feet deep; long-lived and very difficult to remove once established; supports the tall aerial stems without staking.

• Stem

  Stout, upright, 4-angled stems 4 - 8 feet tall; rough-hairy; branching in the upper portions; resinous and aromatic; the squared stem is a diagnostic feature.

• Leaves

  Opposite, broadly ovate, toothed leaves 4 - 14 inches long; rough-hairy texture; upper stem leaves are perfoliate (fused at the base to encircle the stem, forming a water-holding cup); lower leaves have petioles.

• Flowers

  Bright yellow, sunflower-like flowers 2 - 3 inches across; 20 - 30 yellow ray petals surrounding a yellow-brown central disk; produced in open, branched clusters on the upper stems from July through September.

• Fruit

  Large, flat, winged achenes 0.5 - 0.75 inch across; seed heads are flat discs from which the achenes radiate; highly attractive to seed-eating birds.

Known Varieties

Common cultivars worth knowing

• Straight Species

  The native species grown from seed; only form generally available. Straight species is the most wildlife-valuable and ecologically appropriate form. Select regionally sourced seed for best local adaptation.

  Best for: Native prairie, rain garden, back of border, wildlife garden, zones 3 - 9