Table of Contents for Entire-leaf Rosinweed (Silphium integrifolium)
Entire-leaf Rosinweed (Silphium integrifolium) is a herbaceous perennial that is native to the midwestern United States and the province of Ontario in Canada. This plant is a host to a moth and a butterfly and is an important nectar source for other insects. Growing from 1 to 6.5 feet tall, this species grows in open areas such prairies, roadsides, and railroads. The yellow flowers bloom from July to September and the plant is hardy in zones 4-8.
Taxonomy and Naming of Entire-leaf Rosinweed (Silphium integrifolium)
Entire-leaf Rosinweed (Silphium integrifolium) was named and described by Andre’ Michaux, a French botanist, in 1803. It still has the same name and is a member of the Aster Family (Asteraceae).
This species has two varieties:
- var. integrifolium: has 12-22 florets per flowering head
- var. laeve: has 20-36 florets per flowering head
Meaning of the Scientific and Common Names
The genus name, Silphium, is derived from a Greek word that originated from a resin-bearing plant (Missouri Botanical Garden). The species name, integrifolium, is Latin for entire leaves (Missouri Botanical Garden).
Common Name and Alternative Names
The common name comes from the entire leaves of the plant.
- Plant Type: This plant is a herbaceous perennial.
- Height: 1.5 to 8 feet tall
- Stem: The stems are erect and glabrous to scabrous and sometime glaucous (Flora of North America).
- Leaves: The leaves are opposite, sessile, lanceolate to ovate, and have serrate to entire margins (Flora of North America). The leaves are 1 to 9 inches long and 0.04 to 4 inches wide. The lower surface of the leaves may be glabrous or pubescent.
- Flower color: yellow
- Blooming period: This plant blooms from July to September.
- Fruiting type and period: This plant has achenes that mature in the late fall and winter.
Range of Entire-leaf Rosinweed in the United States and Canada
This species is native in the midwestern United States and is adventive in the province of Ontario and the state of Massachusetts in the United States. It is considered to be rare in the states of Michigan, South Dakota, Nebraska, New Mexico, Texas, and Wyoming.
This species grows in open areas such as prairies (MacRoberts and MacRoberts 1995), floodplains (S. integrifolium var. laeve) (Noteworthy collections 1986), roadsides (Leidolf, et al 2002), and railroads (Henry 1985). In Missouri this species has been noted to be on circumneutral and calcareous prairies (Steyermark 1934).
The members of the Silphium genus are hosts to the bordered patch (Chlosyne lacinia) butterfly in the western United States and the silphius borer moth (Papaipema silphii) throughout. This particular species also hosts the rosinweed moth (Tebenna silphiella) (Grote 1881).
Other Supported Wildlife
This species is an important nectar source to other butterflies, skippers, bees, and wasps.
Frequently Asked Questions
Does this plant have any ethnobotanical uses?
The Native American Ethobotanical Database shows that this species has been used for pain relief, orthopedics, and for urological disorders.
How is this plant distinguished from other Rosinweeds (Silphium spp.)?
This species is similar to the rough-stem rosinweed (Silphium radula) (Weakley, et al 2022) and the starry rosinweed (S. astericus) (FNA), but differs in having opposite leaves, while the other two have alternate leaves.
Is this plant invasive?
This plant has been noted as being invasive in gardens (Missouri Botanical Garden).
Gardening with Entire-leaf Rosinweed
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This species is hardy in zones 4-8. If your garden is within these zones and you have the right growing conditions (soil, moisture and exposure), you may well be able to grow this plant. However, if planted outside of its range, the hosted species may not recognize the plant or be harmed by ingesting a different species with an unfamiliar chemical composition. For instance, only part of the range of the species overlaps with the bordered patch butterfly. This butterfly would not be benefited by those plants in the east.
This species grows in full sun and medium well-drained soil (clay).
- Grote, Augustus Radcliffe. 1881. A Choreutes on Silphium integrifolium. Papilio 1(3): 40.
- Henry, R.D. 1985. A survey of some remnants of the native flora of west-central Illinois, USA. Phytologia 57: 97-106.
- Leidolf, Andreas, Sidney McDaniel, and Tim Nuttle. 2002. The Flora of Oktibbeha County, Mississippi. Sida 20: 691-765.
- MacRoberts, Barbara R. and Michael H. MacRoberts. 1995. Vascular flora of two calcareous prairie remnants on the Kisatchie National Forest, Louisiana. Phytologia 78: 18-27.
- Noteworthy Collections. 1986. Silphium integrifolium var. laeve. Madrono 33: 315.
- Steyermark, Julian. 1934. Some features of the flora of the Ozark region on Missouri. Rhodora 36: 214-233.
- Weakley, A.S., and the Southeastern Flora Team. 2022. Flora of the Southeastern United States. University of North Carolina Herbarium, North Carolina Botanical Garden.