Compass Plant, Robinson's compassplant
Silphium laciniatum
Family: Asteraceae or Compositae
What it is like
Silphium laciniatum is a PERENNIAL growing to 2 m (6ft) by 0.6 m (2ft in). See above for USDA hardiness. It is hardy to UK zone 4. It is in flower from July to August, and the seeds ripen from August to September. The species is hermaphrodite (has both male and female organs) and is pollinated by Insects. Suitable for: light (sandy), medium (loamy) and heavy (clay) soils. Suitable pH: mildly acid, neutral and basic (mildly alkaline) soils. It can grow in semi-shade (light woodland) or no shade. It prefers moist soil.
Height (m): 2
Where it is found
Prairies and glades. Calcareous or sandy soils and prairies in Texas.
Central N. America - Ohio to Minnesota, south to Alabama and Texas.
Conservation Status:
Countries/locations it is found in
How it is used
Food
Rating: 2
A resin exudes naturally from the plant, and can also be obtained by incision. It is an inexpensive substitute for mastic and is used as a chewing gum to sweeten the breath. It forms on the upper part of the flowering stem.
Gum: can be chewed as a chewing gum or can often be used as a sweetener or thickening agent in foods.
Medicine
Rating: 2
The resin obtained from the plant is diuretic. It imparts a strong aromatic odour to urine. A tea made from the roots is vermifuge and a tonic for general debility. It is used as an expectorant in coughs and other pulmonary ailments. A decoction of the smaller roots has been used as an emetic. A tea made from the leaves is emetic, it has also been used in the treatment of coughs, lung ailments and asthma.
Diuretic: Acts on the kidneys, promoting the flow of urine.
Emetic: Induces vomiting.
Expectorant: Clears phlegm from the chest by inducing coughing.
Tonic: Improves general health. Slower acting than a stimulant, it brings steady improvement.
Vermifuge: Expels and kills internal parasites.
Other
Rating:
Gum: Gums have a wide range of uses, especially as stabilizers, emulsifiers, thickening agents, adhesives etc.
Industrial Crop: Hydrocarbon: Materials, chemicals and energy include bioplastics, rubber, biomass products gasoline, jet fuel, diesel, butane, propane, biogas. Plants are usually resprouting plants and saps.
Management: Standard: Plants grow to their standard height. Harvest fruit, seeds, or other products. Non-Destructive management systems.
Wild Crop: Some wild plants have strong historical or contemporary use. Although they are not cultivated crops, they may be wild-managed.
Industrial Crop: Hydrocarbon: Materials, chemicals and energy include bioplastics, rubber, biomass products gasoline, jet fuel, diesel, butane, propane, biogas. Plants are usually resprouting plants and saps.
Management: Standard: Plants grow to their standard height. Harvest fruit, seeds, or other products. Non-Destructive management systems.
Wild Crop: Some wild plants have strong historical or contemporary use. Although they are not cultivated crops, they may be wild-managed.
Carbon Farming: Plants that can be a critical part of the solution to climate problems. The Carbon Farming Solution - Eric Toensmeier.
Food Forest: Plants for Edible Forest Gardens and Food Forests.
How it is grown
Succeeds in any ordinary garden soil. Prefers a deep moisture retentive moderately fertile soil that is not too nitrogen rich, in sun or dappled shade. Prefers a shady position. A very ornamental plant. Leaves of young plants tip vertically and align themselves north to south to minimise exposure to the midday sun. Plants have a deep and extensive root system which makes transplanting difficult. The plant is heat tolerant in zones 9 through 5. (Plant Hardiness Zones show how well plants withstand cold winter temperatures. Plant Heat Zones show when plants would start suffering from the heat. The Plant Heat Zone map is based on the number of "heat days" experienced in a given area where the temperature climbs to over 86 degrees F (30°C). At this temperature, many plants begin to suffer physiological damage. Heat Zones range from 1 (no heat days) to 12 (210 or more heat days). For example Heat Zone. 11-1 indicates that the plant is heat tolerant in zones 11 through 1.) For polyculture design as well as the above-ground architecture (form - tree, shrub etc. and size shown above) information on the habit and root pattern is also useful and given here if available. The plant growth habit is a runner spreading indefinitely by rhizomes or stolons.
Propagating it: Seed - best sown as soon as it is ripe in a greenhouse. Prick out the seedlings into individual pots as soon as they are large enough to handle and plant them out in the summer. Division in spring. This is very difficult due to the deep and extensive root system.
Best place to grow: Cultivated Beds;
Habit: Perennial
Hardiness: 4-8
Growth:
Soil: Light (sandy), medium, heavy (clay)
Shade: Semi-shade, no shade
Moisture: Moist
Things to keep in mind
There is a report that the plant might be toxic.