Photo: Greg Hume — CC BY-SA 4.0 · source
Survives zone 4 through 9
⚠ Honestly: can be tapped, but sap sugar is lower than the other birches here — worth tapping only if it's what you already have; paper, yellow and silver birch are better choices.
- Hardiness
- Zone 4 to 9
- Habit
- Tree
- Edible part
- Sap
- Ripens
- Early spring at the thaw — a short 2–3 week sap flow
- Mature size
- Large tree to ~25 m — not containerable
- Light
- Full sun
- Soil pH
- 6.0–7.5 (lime-tolerant)
- Environment
- Riparian
- Status
- Sap
- Years to fruit
- 3–4 yrs
- Pollination
- Wind-pollinated, monoecious catkins — irrelevant to a sap crop
Growing guide
Fertilizing. Needs little routine fertilizing in decent soil; keeping trees well-watered and adequately fed mainly matters for maintaining vigor and resistance to bronze birch borer. On alkaline soil, treat iron chlorosis directly with a chelated iron product rather than blanket-feeding.
How it spreads. Does not sucker or self-seed as a garden nuisance, but its shallow, wide-spreading fibrous root system can heave nearby pavement and outcompete lawn grass — best kept well clear of paths and foundations.
Growing tips. Strongly resistant to the bronze birch borer that devastates white-barked birches, provided the tree isn't drought-stressed. On high-pH soils it's prone to iron chlorosis (yellowing leaves with green veins); best sited in consistently moist, acidic soil.