A Guide to Green Ash Trees

Green ash trees are one of the most planted urban trees in the Midwest, yet many homeowners don’t know they have them, let alone how to care for them. In this guide, we’ll help you identify if you have a green ash tree and how to keep it healthy.

What to Look For

You can identify ashes by looking for trees with opposite branching (not many trees do this) and compound leaves formed by clusters of leaflets. Ashes also tend to have distinctive bark that vary by species.

When it comes to green ash trees specifically, look for compound leaves with 5 to 9 leaflets, each of which can grow as long as your hand. The leaflets are usually a long oval shape with a tapering base. They’re shiny green on top, while the lower surfaces are lighter green. Size-wise, green ashes are fairly large and can grow to 70 feet tall and 40 feet wide.

Why We Like Them

Green ashes are one of the most adaptable trees that grow here in the Midwest. They have a high tolerance for poor growing conditions and can be used as a street or shade tree in urban areas where other species might not thrive. In addition to their toughness, they’re fast-growing when planted in a full sun site in moist, well-drained soils. Green ashes can also tolerate a wide range of soil conditions.

How to Care for Green Ash

Light: Make sure it’s positioned in a place that gets plenty of sun.

Soil: These trees thrive in moist, fertile soil conditions. They aren't particular when it comes to pH levels, but better growth can happen in loamy, sandy, or clay soil types.

Watering: They prefer to be kept consistently moist, but some standing water or dry conditions won't kill this tree off.

Fertilizer: If you have a mature tree already established in your garden, they won't need fertilizing unless they're showing signs of stress.

Pruning: Young green ash will need more pruning to help manage their form, but mature trees won't need much pruning. It's only necessary if branches become brittle or diseased if they have suffered weather damage or they're growing too wide or tall for the space.

Pests: Green ash is susceptible to emerald ash borers. They can feed on your tree from the inside and prevent it from being able to carry nutrients and moisture effectively. In fact, an infestation can kill a green ash within a few years.

If you suspect your green ash tree has an emerald ash borer infestation, it's best to consult a professional - and quickly. Here at Arb Tech, we can determine what’s best for your tree, whether that’s an application of pesticides or removal.