Dwarf Birch Betula nana
Dwarf Birch is a perennial shrub native to Alaska, Canada, and Greenland. It grows to 3 ft and blooms May in full sun – part shade, with brown fruit. A keystone plant for native insects and the food web.
More about this plant
Betula nana, the dwarf birch, is a species of birch in the family Betulaceae, found mainly in the tundra of the Arctic region. Wikipedia →
Growing & care
USDA PLANTS · TRY- Sun
- Full sun – part shade
- Soil & moisture
- Low moisture
- Soil pH
- 4.9–6.5
- Fertility need
- Low
- Adapts to
- Coarse (sandy), Medium (loam), Fine (clay)
- Hardiness
- USDA zone 3+
- Drought tolerance
- Low
- Shade tolerance
- Low
- Wet-soil tolerance
- High waterlogging
- Height
- 3 ft
- Mature width
- ~ 3 ft wide DERIVED derived estimate — open-grown crown allometry (height × growth-form ratio); not a measurement
- Spacing
- 5–6 ft apart from USDA planting density
- Spread
- None — clumping
- Growth rate
- Moderate
- Growth form
- Multiple stems
- Lifespan
- Perennial · moderate
- Foliage
- Deciduous broadleaf · fine texture
- Active growth
- Summer
- Fruit
- Brown
- Propagate by
- Seed, Bare root, Container
- Seed starting
- Needs cold stratification a cold-moist spell before it germinates
- Seeds ripen
- Summer seed-collection / harvest window
- In the trade
- Contract growing only
- Deer browsing
- Low often deer-resistant
- Resprouts if cut
- Yes regrows after top-kill
Sow timing keys off your local last- and first-frost dates.
Wildlife & pollinators
How pollinator value is scored →❧ Caterpillar hosts ~411 caterpillar species · keystone genus
Betula supports ~411 caterpillar species.
Native butterfly & moth caterpillars are the base of the terrestrial food web — most songbirds rear their young almost entirely on them. As a host for native Lepidoptera this is a powerhouse genus.
Recorded feeding on Betula in North America, including:
+ 8 more species → ↑ show fewer
Wildlife & visitors 2 birds · 1 mammal
Open records of who else uses Dwarf Birch — a generalist food-web signal, kept separate from the keystone Ecological Value.
Recorded eaten by 2 birds and 1 mammal species (fruit, seed, browse):
Across 210 U.S. vegetation-survey plots that recorded Dwarf Birch, these catalog species turned up most often in the same plot — a real field co-occurrence signal, not a planting prescription.
How we know this (4) Methods & honest limits
We read each species’ measured specific leaf area (leaf area per unit dry weight) from the Global Spectrum dataset and band it: thin & fast (high SLA), medium, or thick & tough (low SLA). The global median is about 10 mm²/mg.
Honest limits: A species-mean from pooled measurements — individual plants vary with light and site. A broad strategy signal, not a precise per-plant figure.
A recorded categorical fact: each species is tagged C3 (standard), C4 (heat/water-efficient) or CAM (succulent, night-time CO₂ uptake) — or a facultative combination. We only show a trait card for the noteworthy C4/CAM cases; C3 is the unremarkable majority, kept in the data but not surfaced as a card.
We take the plant’s U.S. county range and look up each county’s long-term climate, then summarise: native rainfall = the median annual rainfall across its counties; heat tolerance = the warm end (90th percentile) of average temperature across its range (mirroring how our cold-hardiness floor uses an extreme). Counties + medians blunt the roadside/observer bias that makes point-level climate unreliable. Needs at least five placeable counties.
Honest limits: A realized, sampling-biased niche (where it has been recorded, not its physiological optimum), and county climate is coarse — large Western counties span deserts and mountains. Derived guide, never a measured fact.
For woody plants that have a height but no measured crown, we estimate width = height × a crown-to-height ratio fit for that plant’s form (conifers narrower than broadleaf trees, shrubs widest), calibrated on our measured open-grown crowns and capped at the largest one ever measured. A measured crown always wins; herbaceous plants get nothing (no anchor).
Honest limits: A coarse class-median estimate for garden-scale spacing, not a measurement; woody single/multi-stem forms only.
Sources for this entry (38) Open & cited
Cite this page Open data, please attribute
PlantKey’s data is open under CC BY-SA 4.0 — free to reuse and adapt, with attribution and the same licence. Photos keep their own per-image licence + credit (see Sources above).
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