Black Ash Fraxinus nigra
Black Ash is a perennial tree native to Canada and the lower 48 states. It grows to 65 ft and blooms Mar in part shade – shade, with brown fruit. A keystone plant for native insects and the food web.
More about this plant
Fraxinus nigra, or the black ash, is a species of ash native to much of eastern Canada and the northeastern United States, from western Newfoundland west to southeastern Manitoba, and south to Illinois and northern Virginia. Formerly abundant, as of 2017 the species is threatened with near total extirpation throughout its range within the next century as a result of infestation by an invasive parasitic insect known as the emerald ash borer. Wikipedia →
Growing & care
USDA PLANTS · TRY- Sun
- Part shade – shade
- Soil & moisture
- High moisture
- Soil pH
- 4.4–8.2
- Fertility need
- Medium
- Adapts to
- Coarse (sandy), Medium (loam)
- Hardiness
- USDA zone 3+
- Drought tolerance
- Low
- Shade tolerance
- Moderate
- Wet-soil tolerance
- Moderate waterlogging
- Height
- 65 ft
- Mature width
- ≈ 30 ft wide wild/forest-grown — open-grown specimens spread wider
- Spacing
- 7–12 ft apart from USDA planting density
- Spread
- None — clumping
- Growth rate
- Slow
- Growth form
- Single stem
- Lifespan
- Perennial · moderate
- Foliage
- Deciduous broadleaf · coarse texture
- Active growth
- Spring & 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
- Routinely available
- Deer browsing
- Medium moderately palatable
- 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 ~149 caterpillar species
Fraxinus supports ~149 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 an exceptional genus.
Recorded feeding on Fraxinus in North America, including:
+ 8 more species → ↑ show fewer
Wildlife & visitors 1 nectaring
Open records of who else uses Black Ash — a generalist food-web signal, kept separate from the keystone Ecological Value.
1 adult butterfly & moth species is recorded nectaring at its flowers:
Related plants
More Fraxinus →
How we know this (3) 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.
Sources for this entry (36) 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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