Fraxinus americana ‘Autumn Purple’
Family: Oleaceae, Olive

Key Steps

• 1a – Opposite leaf arrangement on stem — go to 2
  • 2b – Leaf compound — go to 14
    • 14a – Leaves are pinnately compound — go to 15
      • 15b – Leaflets are uniform in shape; margins are entire or slightly serrated. Leaf scars do no meet across the stem — go to 16
        • 16b – Bud sits inside the leaf scar. Leaflet margins entire, except for a few faint rounded teeth — White Ash

Description

Leaf: Oddly pinnate, 5-9 leaflets, egg-shaped, long pointed tip. Wedge base. Margins barely toothed or smooth. Very nice maroon/purple fall color.

Bud: Sits within the leaf scar, not on top like green ash.

Leaf Scar: Half circle or shield-shaped, straight across top. Many bundle scars from a continous half circle within leaf scar. Bud sits at top of leaf scar. Leaf scars do not meet across stem.

Stem: Gray-brown, pale lenticles, stout, stiff, compressed at nodes. Long ridges. May be hairy.

Bark: Vertical ridges form a diamond-shape; ridges are flat on top like they’ve been planted.

Pith: Six-sided, white

Flower: Green to reddish-purple, tiny.

Fruit: Samara, single wing shaped like a canoe paddle. Pointed at top, round at other end. 1 to 1 3/4 inches long.

Habit: Large shade tree to 60+ feet tall by 30 feet wide. Several main branches, irregular spreading.

Culture: Performs poorly in Colorado, short lived. Extremely prone to Lilac/Ash borer.

Resources

• Identifying Broadleaf Flowering Trees and Shrubs, CMG GardenNotes #173
• List of trees in this key
• Glossary of Terms
• Front Range Tree Recommendation List
• Online CSU Extension publications on Tree and Shrub Selection