Silphium perfoliatum (Cup Plant, Carpenter’s Weed, Cup Rosin Weed)
Botanical Information
| Family | Asteraceae |
| Genus | Silphium |
| Species | perfoliatum |
| Category | Perennials, Wildflowers & Weeds |
| Origin | Native to Missouri, the United States of America. |
| Ethnobotanical Uses Disclaimer | The roots are diaphoretic (inducing perspiration), used to treat liver and spleen ailments, fevers, internal bruises, debility, ulcers, and as a general alterative restorative. Its gummy sap is a stimulant and antispasmodic. |
Details
| USDA Hardiness Zone | 1a - 6a |
| USDA Hardiness Ref. | |
| Canadian Hardiness Zone | 0a - 5b |
| Canada Hardiness Ref. | |
| RHS Hardiness Zone | H7 |
| RHS Hardiness Ref. | |
| Temperature (°C) | -51 - (-21) |
| Temperature (°F) | -60 - (-5) |
| Height | 1 - 2.5 m |
| Spread | 30 - 90 cm |
| Growth | Fast |
| Flowering Period | July, August, September |
Description and Growing Information
| General Description | Silphium perfoliatum is a sunflower-like herbaceous perennial with tough, erect stems yellow flowers. |
| Landscape | Good for a low-maintenance backdrop to other perennials in rain or naturalized gardens. Will attract birds and butterflies. Needs lots of room to grow, can be weedy. Good for moist locations near water. |
| Propagation | By seed, will self-seed in ideal conditions. |
| Cultivation | Grow in full sun, in moist, rich soil. Tolerant of clay and wet soils as well as some drought once established. |
| Pests | No serious pests or diseases of note. |
| Habitat | Low woods and thickets, meadows, prairie stream or pond edges. |
| Leaf Description | Opposite, basally united in pairs and perfoliate to form a cup shape, broad at base, tapering to a point with coarse crenation (rounded teeth) and palmate venation (several primary veins diverging from a point). |
| Flower Description | Single, sunflower-like heads up to 7.5 cm in diameter with 20 - 40 long, narrow, bright yellow rays and darker yellow centres. |
| Texture Description | Coarse. |
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