Allendan Seed Company

Silphium integrifolium - Rosinweed

Rosinweed - Silphium integrifolium
SKU: 130
Return Policy

Rosinweed (Silphium integrifolium) is a fast-maturing perennial and unbranched except near the top. Its central stem is stout with stiff short hairs, and is usually green but can turn red with bright sunlight. It has opposite, broadly ovate 5" leaves that are also coarsely textured with stiff hairs. A panicle of composite yellow flowers form at the top and resemble small 2" - 3" sunflowers. This is the smallest of all the Silphiums, and it gets its name from the fragrant rosin that it produces, which was chewed as gum by Native Americans.


Soil Moisture:  Moderate, Dry

Sun Exposure:  Full Sun

Height:  4' - 6'

Spread:  2' - 4'

Hardiness Zone:  4 - 8

Bloom Color:  Yellow

Bloom Time:  July, August, September

Attracts:  Birds, Butterflies, Pollinators



Silphium is a genus of flowering plants that are native to North America, and is commonly referred to as rosinweeds. They are very tall perennials that can grow taller than 8 feet, and have yellow flowers that can resemble sunflowers. With rosinweeds, the flower's outer florets are fertile and the inner florets are sterile, but in sunflowers it is the opposite. Silphium is an ancient Greek word for a North African plant whose identity has been lost and was claimed to be extinct in Roman times, but its gum or juice was prized as a medicine and condiment. 

Return Policy

Returns of standard seed mixes and individual species must be made in the original unopened packaging within 10 days of delivery. If you wish to return live plants, you must do so within 5 days of delivery. Returns of standard mixes, individual species, and live plants are subject to a restocking fee of 25%. Custom seed mixes may not be returned. When returning non-damaged goods, the buyer is responsible for shipping charges, and return shipping may be made by whatever means the buyer selects.

Allendan Seed Company warrants that the seed it sells will conform to the label description as required under state and federal seed laws. The seed labels show independent lab testing results, and the absence of weed seed is not represented or guaranteed. It makes no warranties, expressed or implied, of merchantability, fitness for purpose, or otherwise, which would extend beyond such descriptions. In any event its liability for breach of any warranty or contract with respect to such seed or plants is limited to the purchase price only. Allendan Seed Company further limits to the purchase price any liability of any kind on account of any negligence whatsoever on its part with respect to such seed or plants. By acceptance of the seed or plants, the buyer acknowledges that the limitations and disclaimers herein described are conditions of sale and that they constitute the entire agreement between the parties regarding warranty or any other liability.

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