Moss campion grows in tight carpets or mounds in rocky, mountainous regions and tundras. This perennial is also planted in rock gardens due to the attractiveness of its tiny leaves as well as the pink or lavender flowers that bloom profusely in summer. The first flowers of the year will appear on the south side. Moss campion plants have long lifespans, with some in Alaska exceeding 300 years of age.
I. Appearance and Characteristics
Silene acaulis, known as moss campion or cushion pink, is a small mountain-dwelling wildflower that is common all over the high arctic and tundra and in high mountains of Eurasia and North America (Alps, Carpathians, southern Siberia, Pyrenees, British Isles, Iceland, Faroe Islands, Rocky Mountains). It is an evergreen perennial flowering plant in the carnation family Caryophyllaceae.
It is also called the compass plant, since the flowers appear first on the south side of the cushion. (Various other plants also have this name.)
Moss campion is a low, ground-hugging plant. It may seem densely matted and moss-like. The dense cushions are up to a foot or more in diameter. The plants are usually about 0.6 meters (2 feet) tall but may be as high as 1.8 m (6 ft). The bright green leaves are narrow, arising from the base of the plant. The dead leaves from the previous season persist for years, and pink flowers are borne singly on short stalks that may be up to 2.5 centimeters (1 inch) long, but are usually much shorter.
It usually has pink flowers, though very rarely they may be white. The flowers are solitary and star-shaped. The flowers are female, male or hermaphrodite. They are between 6–12 millimeters (1⁄4–1⁄2 in) wide, with hermaphrodite flowers being larger than the female ones. Female flowers produce better quality seeds than hermaphrodites and male flowers produce better quality pollen than hermaphrodites. The cushions can change the gender of their flowers between years. Gender frequencies change with altitude, the frequency of female flowers increasing with higher elevation. They usually appear in June through August. The flowers are held by a calyx which is rather firm and thick.
The sepals are joined together into a tube that conceals the bases of the petals, which are entire. The 10 stamens and 3 styles extend well beyond the throat of the flower. The stems and leaves are very sticky and viscid, which may discourage ants and beetles from climbing on the plant. The variety exscapa has shorter flowering stems. The other variety subacaulescens, from Wyoming and Colorado, has pale pink flowers all summer.
Plants in Colorado have been estimated to reach 75 to 100 years in age, and Alaskan plants may reach 300 years. The oldest known moss campion is 350 years old and has a diameter of two feet.
There is no listing that moss campion is toxic, though it does have saponins which, though toxic, are hard to absorb in the body. They can be broken down by thorough cooking. Its advised to not consume large amounts of this plant.
II. How to Grow and Care
Sunlight
Protection from intense midday sun is beneficial, as moss campion prefers cooler temperatures and partial shade.
Watering
Adapted to the rocky, often cold environments of its native habitat, moss campion has evolved to require minimal water, thriving in conditions where moisture is infrequent. This resilience translates into a watering regimen of once every 1-2 weeks, ensuring that the plant’s water needs are met without over-saturation. Given its preference for well-draining soil and exposure to alpine climates, moss campion is an ideal candidate for outdoor rock gardens. As a cushion-forming perennial, it demonstrates a remarkable ability to conserve water within its dense foliage, a trait that supports both its survival and flowering potential during the brief alpine growing season.
Soil
Moss campion thrives best in rocky, well-draining soil, mimicking its natural alpine habitat, demanding minimal care from gardeners. Special attention should be given to its watering needs: ensure soil moisture is consistent but avoid waterlogging.
Fertilizing
For moss campion, optimal fertilization involves using balanced nutrition fertilizers or high phosphorus options to enhance flowering and vigor. Apply in early spring as growth resumes, and again in midsummer at half-strength. Be cautious not to over-fertilize; a light hand is best, approximating a quarter teaspoon per gallon of water. Adjust frequency and quantity as moss campion moves from active growth to dormancy, reducing applications in fall. Effective fertilization ensures robust health and a vibrant floral display, crucial for moss campion’s success.
Propagation
Moss campion is effectively propagated through cuttings, which involves taking a healthy piece of the plant, typically a non-flowering shoot, and allowing it to root. Cuttings should be placed in a well-draining soil mix and kept under conditions with ample indirect light and stable moisture until roots develop. To mitigate potential issues with rot or disease, the use of a rooting hormone and ensuring good air circulation are practical steps to enhance the success rate of propagation for this cushion-forming perennial.
Transplanting
Optimal transplantation for moss campion flourishes in the season of new beginnings, as gentle warmth and lengthening days encourage root establishment. Seek a sun-kissed spot with sharp drainage to mirror its native alpine terrain, ensuring moss campion’s enduring vitality.
Repotting
Repot moss campion every 2-3 years, best in spring to align with growth spurts. As a low-growing ground cover, moss campion thrives in shallow, wide containers that accommodate its mat-forming habit. Select a pot just one size larger to prevent waterlogging. After repotting, keep soil evenly moist and place in a spot with cool temperatures and full sun to aid recovery.
III. Uses and Benefits
The plant used to be used for children with colic. The raw root skin plants were consumed as a vegetable in Iceland and in Arctic regions.