Leatherleaf is a native perennial evergreen shrub of boreal wet areas. It grows on woody branched stems 8 inches to 4 feet high.
Leaves are alternate, up to 2 inches long and 5/8 inch wide, becoming smaller toward and in the inflorescence. They are leathery, aromatic and poisonous, containing the compound andromedotoxin. The upper surface is an olive green to dark green with some yellowish scales, which turn more brownish with age. The underside has the scales more densely. The leaf base is wedge shaped, the tip acute to rounded with a projecting point of the midvein. The margin of the leaf has very minute teeth but usually hidden as the leaf edge tends to curl under. Stalks are very short. Overwintering leaves may have a reddish color which changes back to olive green in spring, but then fall away when the plant flowers and new leaves are formed. As the photos below show, flowers may appear before or with the new leaves.
The inflorescence is a terminal raceme, up to 5 inches long, rising from the leaf axil with 1 to 15 pendant flowers.
Flowers: Flowers are urn shaped 6 to 7 mm long, with densely hairy stalks, hanging from the raceme but not crowded. Each flower stalk has a pair of bracteoles (very small bracts) at the top of the stalk right against the flower. The calyx has 5 sepals, ovate to more triangular in shape, about 1/3 the length of the corolla to as much as 1/2. The corolla has 5 white petals, united for 3/4 of their length, then narrowing at the throat of the flower before turning slightly outward. Most flowers are bisexual but some are functionally staminate or pistillate. There are 10 stamens with yellowish/brownish anthers. There is a disc containing nectar at the base of the stamens. The ovary is 5 chambered with a single style that is longer than the stamens, just showing at the corolla throat. Flowers form from buds of the previous season.
Seed: Fertilized flowers produce a a 3 to 4 mm long seed capsule, 5 valved, with the sepals persisting on the end. Seeds are small, 1mm, wedge-shaped and golden brown. When the capsule is dry it forms slits and seeds shake out by wind action or other distrubances. Capsules persist through the winter.
Habitat: Leatherleaf is a plant of boreal bogs, boggy swamps and wetlands of northern climate zones, forming dense thickets if not shaded out by Black Spruce or Tamarack. It is acid tolerant and usually is found where the pH is less than 5. It is one of the first bog plants to flower. Burning stimulates growth. While seeds may be started for new plants, they need cold stratification and germinate on sphagnum or sedge mats. The root has rhizomes, and root division is a quicker and best way to obtain new plants by dividing rooted clumps.
Names: The genus Chamaedaphne is from the Greek and references a European tree. The two parts are chamai, meaning near the ground, or dwarf, and daphne meaning 'laurel' - the dwarf laurel tree. Together the botanical reference is to a low growing shrub with persistent leaves. The alternate common name of Dwarf Cassandra is a later name for that European tree. The species name, calyculata, is Latin meaning 'with a small calyx'.
The author names for the plant classification are: First to classify was '(L.)' which refers to Carl Linnaeus (1707-1778), Swedish botanist and the developer of the binomial nomenclature of modern taxonomy. His work was amended by ‘Moench’ which is for Conrad Moench, (1744-1805), German botanist, Professor of Botany at Marburg, author of Methodus Plantas hirti botanici et agri Marburgensis, and who named the genus Echinacea.
Varieties: At one time 3 variety names were published: var. angustifolia, var. latifolia and var. nana. None are accepted today and all are synonyms for Chamaedaphne calyculata.
Above: Leatherleaf grows on woody branching stems with the prior years leaves remaining until flowering. Drawing from Britton, N.L., and A. Brown. 1913. An illustrated flora of the northern United States, Canada and the British Possessions. 3 vols. Charles Scribner's Sons, New York.
Below: The inflorescence is a terminal raceme of 1 to 15 pendant flowers with small leaves between them.
Below:- 1st photo - The urn shaped flowers have united petals until the narrowest part of the throat, then the tips reflex. Only the style protrudes from the corolla. 2nd photo - the calyx has 5 triangular/ovate lobes with 2 small bracteoles at the base.
Below: The upperside and underside of the new leaves that form after flowering. Note the brownish/yellowish scales, more pronounced in the 3rd photo of late summer.
Below: An old leaf from the prior season during Spring flowering with new growth at the twig.
Below: A clump of Leatherleaf in flower in in mid-May 2019. Spring warm-up was late and these plants are flowering before leaf-out.
Notes: Leatherleaf was introduced to the Wildflower Garden by Eloise Butler in 1907 with plants sourced at Mahtomedi Mn, a spot where she obtained a number of different bog and wetland species in 1907. Later, she planted it again and again in the years 1910, '12, '14, '17, '18(2x), '21, '24(2x), '25, '27 and '32. Establishment in the small old bog of the Wildflower Garden was obviously difficult and not successful. Martha Crone added plants in 1947. It is no longer extant, but is found nearby in the Quaking Bog.
Leatherleaf being a boreal bog plant, is found in nearly all the Canadian Provinces, but in the United States it is restricted to Minnesota, Iowa and states eastward to the coast and north of the Ohio River, plus the Carolinas. Within Minnesota distribution is concentrated in the counties NE of a line from Hennepin, Ramsey and Washington Counties in the SE, northwest Roseau County in the far NW.
References: Plant characteristics are generally from sources 1A, 32, W2, W3, W7 & W8 plus others as specifically applied. Distribution principally from W1, W2 and 28C. Planting history generally from 1, 4 & 4a. Other sources by specific reference. See Reference List for details.
Identification booklet for most of the flowering forbs and small flowering shrubs of the Eloise Butler Wildflower Garden. Details Here.
Friends of the Wild Flower Garden, Inc. Text and photos are by G. D. Bebeau unless otherwise credited. "www.friendsofthewildflowergarden.org"