One of the tallest flowers to ever grace the prairies of North America is the Compass Plant. Mature specimens can reach 12’ tall making it one of the tallest perennials anywhere. Their impressive height make them eye catching in prairies, meadows, or even along a roadside ditch at 70 miles per hour!
I’ve been in love with these sentries of the plains ever since I first saw them towering over grasses and shorter flowers. And since then I’ve germinated hundreds of these flowers and planting them in various flower beds and micro-prairies around my yard.
In this article:
- What is Compass Plant
- What are the benefits of Compass Plant
- Identification / Characteristics
- How to grow and care for Compass Plant
- What Wildlife, Pests, and Diseases effect Compass Plant
- Where to buy Compass Plant
- Uses of Compass Plant
- Final thoughts
What is Compass Plant
The Compass Plant is a herbaceous perennial native to Central North America. Scientifically known as Silphium laciniatum, it grows 6-12’ tall in full sun and well draining soil. Blooming numerous yellow daisy-like flowers for six weeks in Summer, it attracts numerous long-tongue bees and butterflies.[1][2]
An incredible prairie plant, this is one of the tallest forbs to grace the vast prairies of the great plains in the central US. And not just for it’s height, the Compass Plant also has one of the deepest roots with references stating it can reach 14-16’ deep.[2][3] But it is not just the height and root that are long, in that this plant can live up to 100 years!
The common name, Compass Plant is derived from the belief that the leaves oriented themselves North to South. Thus early pioneers and wagon trains used these leaves as a compass[2][4]. Well, it turns out that this is a growth response to maximize photosynthesis and carbon by the plant, and that fully grown leaves will orient themselves if they are subjected to directional light[5].
Native Range of Compass Plant
The primary native range of the Compass Plant is central North America, from East Texas to Eastern South Dakota, Wisconsin/Michigan, and South to Alabama. This is a prairie plant, and thus it’s range tends to follow that of the great plains.
Compass Plant Reference Table
| Scientific Name | Silphium laciniatum |
| Common Name(s) | Compass Plant |
| Native Range, USDA Zone | Central North America, USDA Hardiness Zone 3-8 |
| Bloom Time | Summer |
| Bloom Duration, Color | 4 weeks, Yellow |
| Height | 6-12′ (2-4 m) |
| Spacing / Spread | 3′ (1m) |
| Light Requirements | Full sun |
| Soil Types | Sandy loam, loam, silt |
| Moisture | Slightly dry to slightly moist |
| Fauna Associations / Larval Hosts | Bees, butterflies |
What are the Benefits of Compass Plant
Beauty
The tall sunflower-like blooms make for an impressive display that is quite noticeable from a distance. It isn’t just one bloom at the end of a stalk, it is many blooms per plant.
Drought tolerant
The deep taproot of the Compass plant make it very drought resistant, as it can access water deeper in the ground. This is a great plant for locations that bake in the sun.
Wildlife
The Compass Plant will attract huge numbers of pollinators to your yard. Bumblebees in particular are attracted and you will hear them buzzing all around the plants in almost a state of euphoria.
Identification and Characteristics of Compass Plant
Stalk
The central stalk is thick and sturdy, and a light green color with white hairs. The upper portion of the plant will branch[6].
Leaf
Compass plant will have leaves at the base (basal leaves) and along the stalk. The basal leaves are quite large, 10-20” long and roughly half as wide. They are hairy, deeply lobed but overall lanceolate in shape. Leaves are smaller further up the stalk[6].
Flower
Numerous individual flowers will occur at the end of a stem. Individual flowers are 3-4” diameter with central disc florets and ray florets on the circumference[6].
Blooming period lasts for 4-6 weeks in mid-summer. Approximately 1-2 months after blooming seed heads will form where the ray florets (petals) once were.
How to save seed
To save seed from Compass Plant, once the seed heads turn brown, cut the stalk below the seed head and place it into a bucket. The seeds are easily dislodged, so try to hold it steady until it is safely over the bucket.
Let the seeds dry in a cool dry place for approximately one week, then gently remove them or shake them loose. Dried seed can be stored in a plastic bag for a couple of years.
Root
The root system of the Compass Plant is a large Taproot that can extend 14′ deep into the soil[2][3]. The diameter starts quite large from the root crown and gently tapers down as the depth of the taproot increases. The root is orange to red in color.
Grow and Care for Compass Plant
Sunlight requirements
Compass Plant should be planted in full sun, which is at least six hours of sunlight per day. However, you should try to maximize sun for the largest and showiest plants[2].
Soil texture requirements
Compass Plant grows best loam, sandy loam, or clay loam soils. The key thing is for the plant to be able to have it’s taproot penetrate to the deep earth.
Moisture requirements
Once established Compass Plant is drought tolerant. But it can be planted on slightly dry sites as long as you help it get established. But overall Compass plant can tolerate slightly moist to dry conditions.
Maintenance
Compass plant may tip over when grown as an isolated specimen or grown on slopes. To better help keep the plant upright naturally, make sure it receives sun from all sides. It also helps to have other plants nearby, as the added competition can help force the plants to grow vertically.
Nonetheless, in high winds without other plants for support (and they must be tall) the plant may require staking.
Fertilizer
As a native plant, the Compass Plant will not require any supplemental fertilizer.
How to Grow Compass Plant from Seed
Compass Plant seed needs exposure to sunlight and cold stratification to break dormancy. Since the seeds are like large papery flakes, it can be difficult to achieve both of these requirements. Personally the easiest way to germinate them is to Winter Sow them, which I strongly recommend. Click here for our guide on Winter Sowing[7].
Process to germinate Compass Plant seed
The following steps assume you have either cold-stratified the seed in the fridge, or are Winter Sowing the seed.
1 – Fill a suitable container with moist potting soil.
2 – Place 3-5 compass plant seeds on top of the soil, making sure they have good contact, but being gentle to make sure the seeds do not break.
3 – Gently sprinkle a handful of soil on top of the seed, but not covering it. This will help make sure there is good contact with the soil, while still allowing sunlight to contact the seed.
4 – Place the container in a location that receives morning sun and afternoon shade. Keep the soil moist by misting or using a spray bottle.
Germination should occur a week or two after Spring temperatures begin to warm up.
NOTE! While I am generally a big fan of separating seedlings, I have had trouble doing so with the Compass Plant. So please note, in my personal experience it is better to thin Compass Plant seedlings rather than trying to separate them when they are immature. You may have more success separating them once the plants are larger and begin showing true leaves.
Establishment
Plant Compass Plant in a location that will receive full sun. Make sure it doesn’t get shaded out. Compass Plant is slow growing and may take several years to flower.
To relate some of my personal experience, I planted Compass Plant seedlings 5 years ago, and they get somewhat shaded by taller surrounding plants. They haven’t flowered (as of 2022), but are still alive. I am hoping that they are just having a tough time with my rocky PA soil, but I am also certain that they need more sun exposure, which at this point is not easy to get! So I will be starting a few more in a more exposed location.
Wildlife, Pests, and Diseases associated with Compass Plant
Pollinators
The Compass Plant will attract numerous species of bees and some species of butterflies. Charles Robertson documented 29 species of pollinator visiting blooms including 13 species of long-tongued bee, 5 short-tongued, and 9 species of Diptera[8].
Birds
Compass Plant is a great specimen for attracting birds, as they will perch on the tall stems as well as eat the seeds. You will be surprised just how many you see doing so, as when they land it is quite noticeable in that you will see the stalk swaying substantially back and forth while the others are still[2].
Pests
There are several insects that will feed on the stems or suck the juices. None of these are overly damaging though, and no treatment is necessary.
Deer and Rabbits
It has been my experience that young foliage may be browsed by deer. But once it is fully grown it gets a rough texture that will dissuade browsing. However, when young Liquid Fence can greatly help protect them.
Livestock
Although not palatable to deer, it has long been observed that general livestock (horse, cattle, sheep) will readily eat hay with Compass Plant material. No ill effects are shown from consuming the plant material[4].
Disease
I’ve not noticed any disease on any plant. Members of the Silphium genus tend to be disease free in my experience.
Where you can buy Compass Plant
Compass Plant is not typically sold in nurseries, as it isn’t a typical ‘garden friendly’ plant. But it can be purchased at specialty nurseries that deal in Native Plants. You can find native plant nurseries near you on our interactive map.
Where to buy seeds
We have ordered a variety of native flower seeds from Everwilde Farms, which you can order right from Amazon through our link on our RECOMMENDED PRODUCTS PAGE. (We may earn a small commission when you purchase through our links, at no cost to you. This helps support our website.)
Uses of Compass Plant
Garden Uses
The best use of the Compass plant would be as component of a micro-prairie, wildflower meadow, or some other type of border garden. It’s towering height mean that will will do well in an open environment where sunlight is available from all sides.
The Compass Plant could be used as the focal point of a traditional formal flower bed. If used in this manner, it would be of benefit to have some other larger plants planted right next to it, as that will help keep it growing straight up and not try to lean to the south or some other direction. Also, it should be given sun from all sides.
Companion Plants
The Compass Plant will grow well with any plant that loves full sun and tolerates medium to dry soil. Some flowers that would do well with Compass Plant include Sunflower, Late Boneset, Spotted Beebalm, Meadow Blazing Star, Rattlesnake Master, Prairie Blazing Star, and Maximillian Sunflower. Some companion grasses would be Big Bluestem, Little Bluestem, and Indian Grass.
Native American & Medical Uses
Sixteen uses of Compass plant have been documented for 7 Tribes. Uses range from smaller roots used as an emetic, using the inner stem as chewing gum, as a ceremonial medicine, and a veterinary aid for horses[9]. The roots of Compass Plant are being researched for other compounds that may prove toxic to cancer cells. Research is on-going[10].
Final Thoughts
The Compass Plant is an amazing flower that is not well known outside of native plant communities. It’s height, blooms, and wildlife attracted are amazing, and it could be used more in traditional landscaping, provided it is given some competition & complete sun exposure.
Find more native plants here
References:
[1] – Silphium laciniatum, USDA NRCS. Accessed 06MAR2023.
[2] – Wynia, R., 2009. Plant Guide for compass plant (Silphium laciniatum L.) USDA-Natural Resources Conservation Service, Kansas Plant Materials Center, Manhattan, Kansas 66502. Accessed 06MAR2023.
[3] – Weaver, John Ernest. “Classification of root systems of forbs of grassland and a consideration of their significance.” Ecology (1958): 394-401.
[4] – Thomas Meehan. The native flowers and ferns of the United States in their botanical, horticultural and popular aspects. Series I-II, United States Patent and Trademark Office, 1878, pp.302
[5] – Zhang, Hanzhong, John M. Pleasants, and Thomas W. Jurik. “Development of leaf orientation in the prairie compass plant, Silphium laciniatum L.” Bulletin of the Torrey Botanical Club (1991): 33-42.
[6] – Robinson, Benjamin Lincoln. “Silphium laciniatum L.” Botanical Gazette 16.4 (1891): 114-115.
[7] – Auffenorde, T. M., and W. A. Wistendahl. “Demography and persistence of Silphium laciniatum at the OE Anderson Compass Plant Prairie.” Proceedings of the Eighth North American Prairie Conference, ed. R. Brewer. Western Michigan University, Kalamazoo. 1982.
[8] – Robertson, Charles. “Flowers and insects; lists of visitors of four hundred and fifty-three flowers.” (1928).
[9] – North American Ethnobotany Database. Silphium ILaciniatum. Accessed 14MAR2023.
[10] – Williams, Russell B., et al. “Digging Deep for New Compounds from the Compass Plant, Silphium laciniatum.” Journal of Natural Products 78.8 (2015): 2074-2086.
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