Green Ash: A Fast-Growing Native with a Complicated Story
If you’re looking for a fast-growing native tree that can handle tough conditions, green ash (Fraxinus pennsylvanica) might catch your attention. This hardy North American native has been a popular choice for decades, but recent developments have dramatically changed the conversation around planting ash trees. Let’s dive into what makes this tree special—and why you might want to think twice before adding one to your landscape.
Meet the Green Ash
Green ash is a deciduous tree native to much of North America, naturally occurring across an impressively wide range. You’ll find this adaptable species thriving from the Canadian provinces of Alberta, Manitoba, New Brunswick, Nova Scotia, Ontario, Prince Edward Island, Quebec, and Saskatchewan, all the way down through most of the continental United States.
This tree has quite a few botanical aliases, having been known by names like Fraxinus lanceolata and Fraxinus campestris over the years. But regardless of what you call it, green ash is unmistakably a member of the ash family, with its characteristic compound leaves and distinctive branching pattern.
What Does Green Ash Look Like?
Green ash is definitely not a shrinking violet in the tree world. This fast-growing giant can reach up to 80 feet tall at maturity, though you’ll typically see it hit around 35 feet after 20 years of growth. The tree forms a single crown with an erect, graceful shape that provides excellent shade coverage.
The foliage is where green ash really shines aesthetically:
- Compound leaves with a yellow-green color during the growing season
- Dense summer foliage that creates excellent shade
- Spectacular yellow fall color that’s quite conspicuous
- Coarse texture that adds visual interest to the landscape
The flowers are small and green, appearing in late spring, though they’re not particularly showy. The tree is wind-pollinated, so it doesn’t rely on attracting pollinators with flashy blooms.
Growing Conditions: The Good News
Here’s where green ash really earns its reputation as a tough, adaptable tree. This species is remarkably tolerant of various growing conditions:
- Soil flexibility: Adapts to coarse, medium, and fine-textured soils
- pH tolerance: Thrives in soils ranging from 4.7 to 8.1
- Moisture adaptability: Handles both wet and dry conditions (facultative wetland status in most regions)
- Temperature hardy: Survives temperatures as low as -47°F
- USDA Hardiness Zones: 3-9
Green ash is particularly valuable for challenging sites where other trees might struggle. It can handle urban conditions, compacted soils, and seasonal flooding—making it a go-to choice for difficult landscaping situations.
The Emerald Ash Borer Problem
Now for the complicated part. Despite all of green ash’s positive qualities, there’s one major factor that has changed everything: the emerald ash borer (EAB). This invasive insect has devastated ash populations across North America since its introduction in the early 2000s.
EAB larvae tunnel under the bark of ash trees, disrupting the tree’s ability to transport water and nutrients. The result is usually death within 2-4 years of infestation. Millions of ash trees have been lost to this pest, fundamentally altering forest ecosystems and urban canopies across the continent.
Should You Plant Green Ash?
This is where the decision gets tricky. Green ash is undeniably a valuable native species with excellent growing characteristics, but the EAB threat makes it a risky long-term investment. Here are the key considerations:
Arguments for planting:
- Supporting native biodiversity
- Excellent adaptability to tough growing conditions
- Fast growth provides quick results
- Beautiful fall color and summer shade
- Some trees can be treated to prevent EAB damage
Arguments against planting:
- High risk of EAB infestation and tree death
- Treatment costs can be significant over time
- Large mature size requires significant space
- Relatively short lifespan even without EAB
If You Decide to Plant Green Ash
Should you choose to take on the challenge, here’s how to give your green ash the best chance of success:
Planting tips:
- Plant in spring after the last frost (needs at least 120 frost-free days)
- Choose a location with plenty of room for mature size
- Ensure good drainage, though the tree handles periodic flooding
- Space trees 300-800 per acre if mass planting
Care requirements:
- Minimal fertilization needed (medium fertility requirement)
- Moderate drought tolerance once established
- Benefits from cold stratification if starting from seed
- Regular monitoring for EAB signs
- Consider preventive EAB treatments in affected areas
Native Alternatives to Consider
Given the EAB situation, you might want to consider other fast-growing native trees that can provide similar benefits without the pest risk. Depending on your location and specific needs, alternatives might include native oaks, maples, or hickories that can provide comparable shade and ecological value.
The Bottom Line
Green ash represents both the promise and peril of working with native plants in a changing world. It’s a genuinely excellent tree with outstanding adaptability and aesthetic appeal, but the emerald ash borer threat makes it a complex choice for today’s gardeners.
If you’re in an area where EAB isn’t yet established and you’re willing to commit to monitoring and potentially treating your tree, green ash can still be a rewarding addition to large landscapes. However, for most gardeners, exploring other native alternatives might be the wiser long-term strategy. Whatever you decide, make sure you’re purchasing from reputable nurseries and never moving ash materials from infested areas—we all have a role to play in slowing the spread of this devastating pest.
