Dwarf Birch is a deciduous, low and spreading shrub. Native to tundra landscapes, it is cold-hardy in Zones 2 through 7 and provides year-round interest. Generally, this plant is called Betula nana though other hybrids (below) are also commonly called Dwarf Birch. Part of the Betulaceae family, it is related to more than 150 species of trees and shrubs. The family contains all birch varieties and other ornamentals such as timber and nut trees of the Northern Hemisphere.
Half-inch leaves of Dwarf Birch are thick and leathery upon rather hairy twigs. Flowering in May, the male catkins can be as long as a full inch, while female catkins are smaller. Each flower is either male or female, while both sexes can grow on the same plant. Seeds ripen in July, producing narrow-winged seeded fruits, allowing pollination by the wind.
|Botanical Name||Betula nana|
|Common Name||Dwarf Birch|
|Plant Type||Deciduous shrub|
|Mature Size||Six to 48 inches tall and 18 to 36 inches wide|
|Sun Exposure||Full sun to part sun|
|Soil Type||Well-drained clay, loam, or sand|
|Soil pH||Acid, alkaline, neutral|
|Flower Color||Yellowish brown|
|Hardiness Zones||2, 3, 4, 5, 6, 7|
|Native Area||Alaska, northern Canada to Baffin Island, Labrador, and Greenland|
How to Grow Dwarf Birch
Plant Dwarf Birch in cool weather. Depending on the variety, it grows six to 48 inches tall and spreads between 18 and 36 inches. Space accordingly at 24 inches wide for smaller varieties like Glengarry and up to 40 inches wide for larger varieties such as Cesky Gold®.
Dwarf Birch prefers full sun, but it will grow in part shade where it can receive direct sunlight for two to six hours of the day. Native to Alaska, northern Canada to Baffin Island, Labrador, and Greenland, it thrives in moist and cool conditions.
Establish Dwarf Birch in a wet, well-drained site with rocky acidic soil. This plant has a complex underground root system, which forms a symbiotic relationship between the Cortinarius sp. mushroom fungi to provide the plant with nitrogen and phosphorous naturally low in native arctic and alpine soils.
Water well during its first year and then an average amount once it is established.
According to the Center for Animal Rehab & Education, birch wood is non-toxic. The University of California reports that birch has minor toxicity and that exposure to the sap may cause skin rash or irritation.
However, WebMD states that birch leaves contain vitamin C and chemicals that "increase water loss through urine." They are used in "spring cures" or for "purifying the blood," contributing to medicine for the kidney, bladder, ureters, and urethra. Birch has also treated arthritis, loss of hair, and achy joints (rheumatism).
Young leaves and raw catkins of Dwarf Birch are edible, according to Plants for A Future, which also reports the buds and twigs can be used in stews for flavor.
Warning: Only consume parts of the plant with the guidance of a medical professional.
- Dwarf birch Glengarry (Betula nana) is common in the United Kingdom. It grows about 20 inches tall, suited as a groundcover in rock gardens.
- Cesky Gold® dwarf birch (Betula x plettkei) is Proven Winners' exceptionally cold-tolerant and deer resistant variety. It grows 24 to 48 inches tall and spreads 18 to 36 inches wide. Colorful foliage changes from the characteristic chartreuse to the autumnal hues of yellow, red, and orange.
- Resin Birch (Betula glandulosa or Betula nana s.l.) is known as the American Dwarf Birch. It is a taller birch shrub that is still considered a dwarf. It grows six feet tall in zones 3-9. Bark is brown to black, twigs are short and glandular. Leaves are paler underneath. The State of Montana Field Guide reports it is similar to Betula pumila because hybrids are so common. Some group all dwarf birch varieties under the Betula nana species name.
- Bog birch (Betula pumila) is also called dwarf birch, sometimes swamp birch, glandular birch, and resin birch. It is another taller variety, reaching between five and ten feet. It is a medium-sized, short-lived, clump-forming shrub that thrives in wet sites. Native to North America, the plant tolerates occasional flooding, alkaline soil, clay soil, and road salt, but it does not tolerate air pollution very well. It can grow erect, trailing, or matted. When planted in residential landscapes, it grows well around bodies of water or in part shade boggy areas. Bog birch is a good choice for rain gardens.
- Water birch (B. occidentalis; B. fontinalis) grows about 30 feet tall and 12 inches wide as a small tree or 20 feet tall as a large shrub. Bark is dark-red and does not peel. Native to moist sites on the western coast of North America, it is sometimes called mountain birch, red birch, or black birch.