Plant library
Pioneer species
Black Alder
Alnus glutinosa
Zones 3–7
The wetland pioneer: a nitrogen-fixing tree that thrives in saturated, compacted clay where nothing else survives, rebuilding soil and priming the ground for the forest that follows.
Sun
Full sun
Water
high
Spacing
15-20 ft apart
Soil
Wet or compacted soil, even standing water, pH 5.0-7.5
Difficulty
easy
Zones
3–7
When to plant
Mar
Apr
Oct
Nov
Timing shifts with your zone — the Genie can pin down exact dates for you.
How to care for it
Plant dormant bare-root trees directly into wet spots other plants can't handle. Stake the first year, then leave alone — it fixes nitrogen from the air and drops leaf litter that feeds everything after it.
Good companions
Nurse tree for wet clay; pairs with willows in reclamation plantings
Harvest
Not a food crop — coppice young stems for garden stakes or chip them for mulch.
Want a plan for growing Black Alder?
Your Genie can give exact timing and care for your zone.
