Culture: Easily grown in average, medium, well-drained soils in full sun. Tolerates poor soils.
Noteworthy Characteristics: Silphium laciniatum, commonly called compass plant, is a native perennial which occurs in prairies and glades throughout most of the State. A tall, sturdy, rough, bristly plant that grows on stiff, hairy, resinous stems to 9′ tall. Features sunflower-like flowers (to 5″ wide) with yellow rays and yellow center disks. Flowers bloom in loose spikes on the upper parts of the plant in summer. Very large, deeply pinnatifid (cut close to the midrib) basal leaves (to 18″ long) are reminiscent of pin oak leaves. Upper leaves are smaller. Basal leaves usually orient themselves on a north-south axis so as to minimize intense overhead sun exposure, thus giving rise to the common name. Split or broken stems exude a gummy, fragrant-but-bitter resin which was used by Native Americans as a mouth-cleansing chewing gum. Many of the silphiums are commonly called rosinweed.
The genus name Silphium comes from the Greek name silphion, used to refer to a North African resin bearing plant. Specific epithet means slashed or torn into narrow segments for the deeply cut leaves.
Problems: No serious insect or disease problems. Slow to establish and may not flower until the second or third year.
Garden Uses: Good height for the rear of the border. Also excellent for naturalizing in prairies, cottage gardens, wildflower gardens or native plant gardens.
All plant information courtesy of the Missouri Botanical Garden
No those aren’t sunflowers, those are Compass Plants! A true icon of the prairies, these lovely plants are an incredible addition to your landscape. Given moist, rich soils, mature compass plants can reach upwards of 8 feet in height. It is quite a sight to see pollinators flit from flower to flower while birds, like Goldfinches, will perch upon the strong stems pecking for insects or seeds.
The name Compass Plant comes from the observation that the leaves have a tendency to orient themselves on a north-south axis. While this certainly helped disoriented early Settlers find their way, the real reason behind this intriguing physiology is to maximize water use in the leaves as well as to increase CO2 gain for the plant. Another interesting aspect of Compass Plant biology is their life expectancy. Given the right conditions, individual plants have been known to live upwards of 100 years! Gardening with Compass Plant is gardening for the future. Sadly, like all other species that live on the prairies, Compass Plants have taken a real hit from habitat destruction. Prairies are some of the most endangered habitats on the planet. Where there was once seemingly endless prairie, there are now only echoes of a lost world. As the great Aldo Leopold once said, “What a thousand acres of Silphiums looked like when they tickled the bellies of the buffalo is a question never again to be answered, and perhaps not even asked.”
Price range: $6.00 through $12.00
