How to Propagate Ash Trees
To some of us, ash trees may seem as American as baseball. After all, baseball bats are traditionally carved from ash. So are bows and tool handles. Ash is a strong, elastic, and hard-working wood.
While there are many varieties of ash found in North America -- including the white ash, black ash, water ash, green ash, pumpkin ash and blue ash -- varieties of the ash tree are also native to Europe, North Africa, and Southwestern Asia.
Ash trees are valued for their quality of wood and for their aesthetic value.
In 2005, the U.S. Department of Agriculture launched an initiative to preserve seeds from ash trees, as several species were threatened by widespread infestation of a pest known as the emerald ash borer.
Seed propagation is not the only method of creating new ash trees. Plants produced from shoot or branch cuttings are a faster and perhaps more efficient way for the home gardener to cultivate new specimens.
Ash trees produce sprays or clusters of long brown or green paired helicopter seeds. Green seeds may be planted immediately and will usually germinate right away, or at the latest during the following spring, unless they are dormant.
Even if seeds are dormant, it is possible to speed up germination by creating conditions that simulate the warm and cold cycles that, in nature, end their dormant period.
To achieve this, plant the seeds about 1/2 inch deep in moist potting soil. Seal the pots in a plastic bag. Store them in a refrigerator for 90 days. Next, store them in a warm place for an additional 90 days. After a third cycle in the refrigerator, the seeds should be ready to germinate and you will have shortened a 1.5 year process into one taking only 9 months.
Another method of propagation is through shoot or branch cuttings. Make sure you take your cuttings from green wood. Take cuttings in spring after the danger of frost has passed. Cut on the diagonal with a clean, sharp tool, and remove all leaves except a few at the tip of the cutting.
Dip the cut ends in rooting hormone, which is typically in white powdered form and available at garden centres. A small package of rooting hormone will be sufficient to facilitate rooting for a small forest of plants grown from cuttings. Using a pencil, make holes in a commercial rooting medium. Insert the cuttings and tamp the medium gently around the cuttings. Reinforce the planted cuttings with supports such as wooden skewers if necessary. Rooting will begin in several months.
Transplant your rooted cuttings to larger pots, or directly outdoors if spring has arrived and danger of frost has passed.