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How to Propagate Ash Trees

mountain ash image by wildman from

The emerald ash borer, a tough little beetle, is working on decimating ash trees in the United States. Because of that, the U.S. Department of Forestry is stockpiling ash tree seeds to be used in case of extinction. Ash tree seeds are deeply dormant when harvested and require special treatment in order to get them to germinate. In the wild, the process takes two years. By warm and cold stratification, you can cut this time down to nine months. Harvest the seed in the fall.

How to Propagate Ash Trees From Seed

Pour seeding mix into the pot to within 3/4 inch of the rim. Water the soil well and allow the tray to drain for two hours.

Plant the seeds 1/2 inch deep and cover with soil.

Seal the pot in the plastic bag and place it in the refrigerator for three months.

Remove the pot from the refrigerator and place it in an area that remains 70 to 75 degrees F. If this is not possible, place the pot on a heat mat set to 75 degrees F. Again, allow the pot to remain for three months.

Return the pot to the refrigerator for an additional three months. Be sure to periodically check the soil and moisten it if it feels dry.

Remove the pot from the refrigerator. Your seeds should germinate within six weeks.

Propagating Ash Trees With Cuttings

Fill the planting pot with sand and water well, allowing the water to drain from the bottom of the pot.

Remove an 8-inch section of green wood from the ash tree. Remove all the leaves except for a few at the top of the cutting.

stem image by Adrian Hillman from

Dip the cut end of the stem into the rooting hormone, then place it into the sand. Make sure you bury at least three nodes (portion of the stem where the leaves were attached).

Place the potted cutting in a warm area, such as on top of the refrigerator. Mist the soil daily to keep it moist, and mist the cutting as well.

Check the cutting to see if it is rooting by gently feeling around the soil. It will begin to root within eight weeks but will take months to develop a strong enough root system to be planted outdoors. As soon as you see new growth you will know that it is time to plant outdoors.


If you would like to help the National Ash Seed Collection Initiative, go to


Harden off your cutting prior to planting it outdoors. You can do this by placing it in a protected, shady area for 10 days. Then, plant it in its permanent location, in full sun.

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