How to Grow River Birch From a Cutting

River birches are widely grown in landscaping as shade trees since they will thrive in areas with poor drainage where other species fail. The unusual, peeling bark provides visual interest in landscaping both for its texture and the cinnamon-brown color it acquires at maturity, which contrasts nicely with the glossy green, serrated leaves during the summer months. Like most birch species, river birch trees will grow from softwood cuttings taken in early summer, but they have a high failure rate so it is best to strike multiple cuttings at once to ensure success.

Things You'll Need

• Anvil shears
• 0.8-percent IBA (indole-butyric acid) rooting talc
• 2-gallon nursery container
• Coarse horticultural grit
• Garden hose mister

Instructions

1. Harvest a river birch cutting for propagation in midsummer around late June. Select a 10- to 12-inch-long section from the tip of a leafy, vigorous branch. Choose one with a 1/4-inch diameter.

2. Sever the cutting at a 45-degree angle 1/2 inch below a set of leaves using anvil shears. Scrape off the bottommost leaves with the blade of the shears so the lower half of the river birch cutting is defoliated.

3. Dip the cutting in 0.8-percent IBA rooting talc so the entire lower half is completely coated. Shake the cutting to dislodge the excess powder.

4. Hold the river birch cutting upright inside a 2-gallon nursery container. Orient the cutting so the talc-treated end is held below the edge of the container and the leafy portion is above the edge.

5. Backfill around the river birch cutting with coarse horticultural grit until the lower half is buried. Shake the container to settle the grit and add more, if needed.

6. Set the nursery container under dappled shade or in a greenhouse with 40-percent shade cloth. Limit direct sun exposure to less than 45 minutes each day.

7. Run water into the nursery container to moisten the sand. Run the water at very low volume around the base of the cutting until the coarse horticultural grit feels moist at a depth of 4 inches. Maintain that level of moisture during the rooting period.

8. Mist the foliage at least five times each day to keep it from dehydrating. Use a garden hose mister, a spray bottle or an automatic misting system, if one is available.

9. Check for roots at the end of summer by tugging on the base of the cutting, or by observing any new growth.

10. Move the river birch cutting to a protected spot for the winter such as a cold frame, greenhouse or a sunny, south-facing wall with barriers against strong wind.

11. Plant the rooted cutting in a permanent bed with sandy, moist soil the following summer around early June. Spread a 1-inch-thick layer of chipped wood or mulch around the base of the tree to protect the roots from drying out.

Tips & Warnings

• River birches grow best in USDA hardiness zones 4 to 9.

References

• Texas A&M University Department of Horticulture; Propagation of Ornamental Trees, Shrubs, and Woody Vines; Fred T. Davies, Jr.
• University of Florida; Environmental Horticulture; Landscape Plant Propagation Information; Betula Nigra
• "American Horticultural Society Plant Propagation: The Fully Illustrated Plant-by-Plant Manual of Practical Techniques"; Alan Toogood; 1999