Green Ash

Fraxinus pennsylvanica

green and gray leaves in black background

A tough, fast-growing native tree that adapts to almost any growing condition while providing excellent shade coverage. Its compound leaves create filtered shade perfect for lawns, and the brilliant golden-yellow fall color rivals any ornamental tree. Though emerald ash borer has created challenges, treated and resistant varieties continue to make Green Ash a valued choice for homeowners seeking a reliable, low-maintenance shade tree.

Sun

Full sun

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Zones

3–9

USDA hardiness

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Height

50-70 feet

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Planting Timeline

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Transplant

Showing dates for Green Ash in USDA Zone 7

All Zone 7 shade-tree →

Zone Map

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Green Ash · Zones 3–9

What grows well in Zone 7? →

Growing Details

Difficulty

Very easy

Spacing30-50 feet

SoilHighly adaptable, tolerates wet to dry soils

pH6.0-8.0

WaterModerate — regular watering

SeasonSpring and Summer

FlavorN/A

ColorMedium green compound leaves, golden-yellow fall color

SizeCanopy spread 30-40 feet

Zone-by-Zone Planting Calendar

Zone	Indoor Start	Transplant	Direct Sow	Harvest
Zone 3	—	June – August	—	—
Zone 4	—	June – July	—	—
Zone 5	—	May – July	—	—
Zone 6	—	May – July	—	—
Zone 7	—	May – June	—	—
Zone 8	—	April – June	—	—
Zone 9	—	March – May	—	—

Complete Growing Guide

Light: Full sun (6 or more hours of direct sunlight a day). Soil: Clay, Loam (Silt), Sand. Soil pH: Acid (<6.0), Neutral (6.0-8.0). Drainage: Good Drainage, Moist, Occasionally Dry, Occasionally Wet. Height: 50 ft. 0 in. - 70 ft. 0 in.. Spread: 35 ft. 0 in. - 50 ft. 0 in.. Spacing: more than 60 feet. Growth rate: Rapid. Maintenance: Medium. Propagation: Seed. Regions: Coastal, Mountains, Piedmont.

Harvesting

Fertilized female flowers give way to the fruit that is a single-winged, dry, flat samara. The wing extends less than half the body of the fruit, and there is a thin seed cavity. There are usually a large number of samara, and they appear narrow, 1 to 2 inches long, and 1/4 inch wide. Their color changes from green to tan as they mature. They hang in dangling clusters and are displayed on the tree from August to October. They can persist on the tree through the winter.

Color: Brown/Copper, Green. Type: Samara. Length: 1-3 inches. Width: < 1 inch.

Harvest time: Fall

Edibility: Bark can be used in cooking as a thickener for soups or mixed with grain in making bread.

Storage & Preservation

Green Ash is a shade tree and does not require post-harvest storage or preservation methods typical of produce. However, if propagating from seeds or cuttings, store seeds in cool, dry conditions (32-41°F) with 30-40% humidity in sealed containers for up to one year. Fresh cuttings should be kept moist in a cool location. For preserved wood/lumber from pruned branches, store in a dry location away from moisture to prevent rot and fungal growth.

History & Origin

Origin: Central and Eastern Canada to West Central and Eastern US

Advantages

+Attracts: Butterflies, Moths, Pollinators, Small Mammals, Songbirds
+Edible: Bark can be used in cooking as a thickener for soups or mixed with grain in making bread.
+Fast-growing

Companion Plants

The understory plants in our beneficial list — hostas, ferns, wild ginger, Solomon's seal — all succeed here for the same basic reason: they're built for the light conditions a large deciduous tree actually produces. A mature Green Ash at 50–70 feet casts variable dappled shade, and these plants fill that ground without competing meaningfully at the root zone. Ferns and wild columbine are especially tolerant of the shallow, fibrous root competition that surface-feeding trees create. Coral bells and astilbe handle the moisture swings well — wetter in early spring under bare branches, considerably drier by midsummer once the canopy closes. Violets near the drip line are useful because they tolerate both conditions and provide early-season ground cover that keeps weeds down while the tree is still leafing out.

The three harmful companions each cause trouble through a different mechanism. Black walnut (Juglans nigra) produces juglone, a biochemical compound that persists in soil and suppresses root development in nearby plants — Green Ash has more tolerance than, say, tomatoes, but sustained exposure within the walnut's root zone (which spreads well past the canopy edge) still weakens the tree over time. Norway maple is the more immediate practical problem: it's an aggressive, shallow-rooted competitor that crowds out understory plantings and will out-compete young ash trees for both water and light. Eucalyptus works differently again — it releases allelopathic compounds through decomposing leaf litter and root exudates that suppress germination and establishment of nearby plants. Give Green Ash genuine separation from all three.

Plant Together

Wild Ginger

Thrives in partial shade and helps suppress weeds while tolerating ash tree's root system

Hostas

Excellent shade tolerance and complementary root depth, won't compete with ash tree roots

Ferns

Natural woodland companions that thrive in filtered light and help retain soil moisture

Violets

Ground cover that fixes nitrogen and attracts beneficial insects while tolerating shade

Wild Columbine

Native understory plant that attracts pollinators and complements ash tree's natural habitat

Coral Bells

Shade-tolerant perennial that adds color without competing for nutrients at tree level

Astilbe

Thrives in moist, shaded conditions and provides ornamental value under canopy

Solomon's Seal

Native woodland plant with shallow roots that won't interfere with tree's root system

Keep Apart

Black Walnut

Produces juglone which is toxic to ash trees and can cause decline or death

Eucalyptus

Releases allelopathic compounds that inhibit growth of nearby trees including ash

Norway Maple

Dense canopy blocks light and shallow roots create intense competition for water and nutrients

Pests & Disease Resistance

Resistance

Susceptible to emerald ash borer, ash yellows, and various canker diseases

Common Pests

Emerald ash borer, ash flower gall, lilac borer

Diseases

Ash yellows, anthracnose, various canker diseases

Troubleshooting Green Ash

What you'll see, why it happens, and what to do about it.

Bark splitting or D-shaped exit holes in the trunk or main branches, often with S-shaped galleries visible under loose bark

Likely Causes

Emerald ash borer (Agrilus planipennis) — larvae feed in the cambium layer, cutting off water and nutrient flow
Tree stress from drought or poor drainage making it more susceptible to infestation

What to Do

1.Contact your county extension office before doing anything — emerald ash borer is a regulated pest in many states, and treatments or removal may have legal requirements
2.For high-value trees, a licensed arborist can apply systemic trunk injections (emamectin benzoate is the most effective option for established infestations)
3.If the canopy is more than 50% dead, removal is usually the only practical path; plan a replacement planting at least 30 feet from the stump

Leaves with irregular brown or tan dead patches, especially along the edges and between veins, appearing in spring after a wet stretch

Likely Causes

Anthracnose (Gnomoniella fraxini) — a fungal disease that hits during cool, wet springs when leaves are just emerging
Dense canopy or poor airflow slowing leaf dry-off after rain

What to Do

1.Rake and dispose of all fallen leaves in autumn — don't compost them, the fungal spores overwinter in leaf litter
2.Most established trees recover on their own; avoid heavy fertilization after an anthracnose year, which pushes soft new growth that's even more susceptible
3.If the same tree defoliates severely two or three years running, have an arborist assess overall health before considering fungicide applications

Dieback starting at the branch tips and working inward, leaves turning yellow or pale green well before fall, overall decline in canopy density over multiple seasons

Likely Causes

Ash yellows (caused by Candidatus Fraxinus virescence, a phytoplasma) — spread by leafhoppers, no cure exists
Canker diseases (Cytospora or Botryosphaeria spp.) entering through wounds or stressed tissue

What to Do

1.Have a certified arborist confirm the diagnosis — ash yellows and canker decline look similar and the management paths differ
2.For canker: prune out affected branches 6–8 inches below visible discoloration, sterilizing your saw between cuts with 70% isopropyl alcohol
3.For ash yellows: no treatment exists; removal and replacement with a non-susceptible species is the only real option

Frequently Asked Questions

When should I plant a Green Ash tree?▼

Plant Green Ash in early spring or fall when temperatures are mild and the tree can establish roots before extreme heat or cold. Spring planting allows the tree to settle through one full growing season before winter stress. Fall planting works well in most regions except the coldest zones. Avoid planting in peak summer or winter. Container-grown trees can be planted year-round if watered consistently during establishment.

Is Green Ash a good tree for beginners?▼

Yes, Green Ash is excellent for beginners. It's one of the easiest shade trees to grow, adapting to almost any soil type from wet to dry. It tolerates poor soil, compacted earth, and urban conditions without complaint. Minimal pruning and maintenance are required beyond occasional shaping. Its fast growth rate provides quick satisfaction for new gardeners seeking shade coverage without specialized care.

How long does Green Ash take to mature?▼

Green Ash grows rapidly, adding 2-3 feet per year under ideal conditions, reaching 50-60 feet tall at maturity. Full canopy development for adequate shade coverage typically occurs within 5-7 years. However, the tree provides some shade within the first 2-3 years. Maturity takes 20-30 years to reach full height and width, though it becomes a functional shade tree much sooner.

What should I know about Emerald Ash Borer in Green Ash?▼

Emerald Ash Borer is a destructive pest that has killed millions of ash trees across North America. If you plant Green Ash, choose resistant varieties or treated trees from reputable nurseries. Monitor for D-shaped exit holes, canopy dieback, or bark splitting. Professional treatment with insecticides is available but expensive. Consider consulting local extension offices about pest management strategies and variety recommendations for your region before planting.

Can Green Ash grow in wet or clay soil?▼

Yes, Green Ash excels in wet and clay soils where many other shade trees struggle. Its adaptability to poor drainage is one of its greatest strengths, making it ideal for low-lying areas, compacted yards, and regions with heavy rainfall. It also tolerates drought once established. This soil flexibility makes Green Ash an excellent choice for challenging landscape conditions where other trees would decline.

How much shade does Green Ash provide?▼

Green Ash provides excellent, filtered shade through its dense compound leaf structure. The dappled light allows grass and understory plants to thrive beneath the canopy, unlike trees that create complete darkness. At full maturity (50-60 feet tall with broad spread), it shades large areas effectively. The open branching pattern in winter allows some light through, while summer foliage creates substantial cooling for homes and outdoor spaces.