Hardiness: USDA Zone 3a: to -39.9 °C (-40 °F) USDA Zone 3b: to -37.2 °C (-35 °F) USDA Zone 4a: to -34.4 °C (-30 °F) USDA Zone 4b: to -31.6 °C (-25 °F) USDA Zone 5a: to -28.8 °C (-20 °F) USDA Zone 5b: to -26.1 °C (-15 °F) USDA Zone 6a: to -23.3 °C (-10 °F) USDA Zone 6b: to -20.5 °C (-5 °F) USDA Zone 7a: to -17.7 °C (0 °F) USDA Zone 7b: to -14.9 °C (5 °F) USDA Zone 8a: to -12.2 °C (10 °F) USDA Zone 8b: to -9.4 °C (15 °F) USDA Zone 9a: to -6.6 °C (20 °F) USDA Zone 9b: to -3.8 °C (25 °F)
Sun Exposure: Full Sun
Bloom Color: Bright Yellow
Bloom Time: Late Summer/Early Fall
Other details: Average Water Needs; Water regularly; do not overwater
Soil pH requirements: 6.6 to 7.5 (neutral) 7.6 to 7.8 (mildly alkaline)
Patent Information: Non-patented
Propagation Methods: From seed; winter sow in vented containers, coldframe or unheated greenhouse From seed; stratify if sowing indoors
Seed Collecting: Allow seedheads to dry on plants; remove and collect seeds Properly cleaned, seed can be successfully stored
On Aug 15, 2011, PrairieDock from Jerome, IL wrote:
Collect the seeds early, as birds may get the best of them. May need some staking since flower heads can extend over 10 feet in height. Great vertical addition to garden, it will look like the king of your garden as it reaches its maximum height.
On Oct 11, 2004, tcfromky from Mercer, PA (Zone 5a) wrote:
Compass plant is a long lived, tall, from 5 to 10 feet, erect perennial rising from a large tap root as deep as 15 feet.
There were a number of medicinal uses for this plant, it was used to treat general debility, head colds, pain, induce vomiting and rid horses of worms. The dried root was burned during storms to avoid being struck by lightning. Pioneers and Indians alike chewed the resin as a gum, to clean teeth and freshen breath.
On Jun 27, 2004, Liatris from Knox City, MO wrote:
This stately and ornamental prairie plant can be an asset for the rural or suburban gardener. I've been growing it for years, starting out with gathered seeds and endangered roadside roots. I like to grow it alongside prairie dock. The two hybridize readily and subsequent self-seeding will provide transplantable seedlings with a variety of leaf shapes ranged from the extreme dissection of compass plant to the broad oval shape of prairie dock leaves. Silphiums need sun and open space. One way to use them is in an isolated bed surrounded by mowed grass, perhaps accompanied by butterfly weed and culver's root.
This plant has been said to grow in the following regions:
Astoria, Illinois Hanna City, Illinois Jerome, Illinois Calvert City, Kentucky Florence, Mississippi Cole Camp, Missouri Glouster, Ohio Enid, Oklahoma Dalworthington Gardens, Texas Princeton, Texas Leesburg, Virginia