How To Plant and Grow a River Birch Tree

Most ornamental trees are valued for their spring and fall foliage displays, but offer little aesthetic value during the winter. Not the river birch tree.

In late summer and fall, river birches produce attractive reddish-green flowers (catkins) on the ends of the branches. But the most stunning feature of the river birch is its brilliant white bark that peels back in thin layers (also known as exfoliates) to reveal a salmon-colored inner bark. When the tree drops its leaves in the winter, the bark offers an ornamental centerpiece in the landscape that will add magic to even the dreariest day.

While these features apply to most birch trees, the river birch has an advantage as one of the hardiest varieties. It can grow in most regions of the U.S. Here’s everything you need to know about growing a river birch, plus expert tips on where to plant your new tree and how to keep it looking spectacular with regular pruning.

What Is a River Birch Tree?

The river birch (Betula nigra) is a fast-growing, deciduous shade tree that’s prized for its rapid growth, environmental resilience, and ornamental value. It has arched, drooping branches with oval-shaped green leaves and serrated edges. The river birch’s beautiful bark offers year-round beauty along with gorgeous foliage from spring through autumn.

A river birch tree can grow between 40 and 70 feet tall and can grow up to 13 to 24 inches per year so annual pruning is recommended to promote healthy and attractive development.

Where Do River Birch Trees Thrive?

River birch’s native habitat is near river banks. “Like their name suggests, river birch thrive in moist environments and are a great choice for areas with poor drainage,” says Benjamin Hanley, founder and managing director of Hanley Landscape Design. “Rather than fighting against existing site conditions, a good landscape designer uses them to their advantage.”

However, the river birch can tolerate drier soil as the tree matures and the roots become well-established. This makes mature river birch trees relatively drought-tolerant, which is unique among birch varieties. The river birch prefers acidic soil, and can develop iron deficiency if the soil’s pH is above 6.5.

River birches thrive in full sun, and are hardy in USDA Plant Hardiness Zones 4 through 9. They can also tolerate partial shade, particularly when grown in hotter regions such as Zones 8 and 9.

Common Pests and Diseases That Target River Birch

River birch trees are generally more resilient to pests and diseases than other varieties of birch. However, they are still prone to the following:

• Bronze beach borer. A roughly 1/2-inch-long, bronze- and black-colored beetle that bores into a tree’s bark to feed on the cambium layer. Common signs of infestation are yellowing and thinning foliage beginning at the upper canopy, and D-shaped holes in the trunk where the insect bored into the bark.
• Birch leafminer. Roughly 1/8-inch-long, black insects that closely resemble flies. Their larva feeds on the leaves’ green tissue and causes a partial to full browning of the leaves.
• Birch dieback. A disease that causes the branches in the upper canopy to die off. It can be caused by a fungal infection or a bronze beach borer infestation.
• Anthracnose leaf blight. A fungal disease that initially produces brown spots on the leaves until they curl and die back completely.

How to Care for a River Birch Tree

Like most trees, river birch should be installed with 2 to 4 inches of high-quality mulch, but be sure to keep the root collar visible, Hanley notes, which is key to long-term development.

“When the root collar is buried, the tree will struggle to breathe and will often send roots upward in search of oxygen, which leads to issues like root girdling, damage from lawnmowers, and sometimes, short-term or long-term failure,” he says.

Here’s a more detailed look at caring for a river birch:

• Water. Water deeply once or twice a week to keep the soil and roots moist. Maintaining moist soil is especially important during the tree’s first couple years of growth, and during the hot summer months.
• Mulch. Apply a two- to four-inch layer of mulch around the tree’s base for moisture retention.
• Fertilize. Apply a fertilizer formulated for acidic soil as the first leaves start to unfurl in the spring. Prevent iron-deficiency in alkaline soil by providing an iron amendment
• Test the soil. Test the soil’s pH every two to three years. Add a soil acidifier to lower the pH if it’s above 6.5.
• Control pests and diseases. Inspect the tree periodically and eliminate any pests with insecticide or predator insects like lady beetles or pirate bugs. Prune back diseased branches, or use a fungicide for severe infections.

How to Prune a River Birch Tree

The best times to prune river birch are during late spring, late fall and winter. Pruning in the spring before the first leaves emerge will cause the tree to lose sap, and fresh pruning cuts can attract birch borers in the summer.

Prune a river birch with bypass pruning shears or a pole pruner, following these steps:

• Remove stems or branches growing out of the trunk or around the base of the tree (AKA suckers).
• Remove diseased branches as soon as they’re discovered, regardless of the time of year. Sterilize the blade of your cutting tool between cuts to prevent disease spread.
• Remove dead branches.
• Remove branches that are rubbing against each other.
• Trim back branches that are closer than two inches apart to promote airflow through the canopy.
• Trim back branches that detract from the desired appearance and balance of the canopy.

How to Propagate a River Birch Tree

River birch seeds can be harvested from catkins in late spring when they start turning brown, but keep in mind that after the seeds are collected, they should be planted in pots immediately for best results. You can also propagate from cuttings.

Here are steps for propagating a river birch both ways:

Propagating from Seeds:

1. Collect catkins and place them in a dry location inside a paper bag for three to four days, or until the seeds naturally separate from the fruit.
2. Sow a thin layer of seeds in a tray filled with soilless growth media.
3. Place in a protected area with indirect sunlight.
4. Water seeds twice a day until the seeds germinate and sprouts form. This usually takes four to six weeks.
5. Transfer to a nursery pot filled with potting soil mix after the second set of leaves have formed, typically two to three weeks after germination.
6. Keep the soil moist by watering two to three times a week. Keep in a protected area until the following spring. Learn what a tree watering bag is.
7. Transplant the saplings outdoors after spring’s last frost, after acclimating them by setting the pot outside in direct sunlight for about a week.

Propagating from Cuttings:

1. Fill a small nursery pot with a soilless medium.
2. Cut a six- to eight-inch-long section off the tip of a branch, just below a spot where a leaf meets the stem (leaf node), at a 45-degree angle. Place in the potting mixture.
3. Place the pot on a heat mat in a protected area with indirect sunlight.
4. Mist the cutting twice a day. River birch cuttings require mist to successfully root.
5. After about six weeks, check for root development by gently tugging on the cutting and feeling for resistance.
6. Transfer to a larger pot filled with potting soil after the roots have formed.
7. Keep the pot in a protected location until the following spring, then transplant into the ground after the last frost

FAQ

Can I plant a river birch near my house or driveway?

Since the roots of a river birch will aggressively seek out water, especially when planted in a dry area, they should not be planted near septic systems, pools, or house foundations, Hanley says. However, he has had success planting river birches near a driveway, as long as the placement is well thought out.

“We planted river birch in a part of the property with dense clay soil, which naturally retains water,” Hanley says of one particular landscape project. “The trees were placed at the lowest point of the driveway to help absorb stormwater runoff. The result is a beautiful, functional barrier of river birch that adds character while managing water on-site.”

How much water does a river birch need?

According to the U.S. Forest Service, during the growing season, a slow (2-3 hours), deep (8-18 inches) watering once per week is a general rule for maintaining adequate soil moisture for a river birch. Watering should be decreased by late August to allow for proper winterization of a tree.

About the Expert

Benjamin Hanley is an award-winning landscape designer and founder of Hanley Landscape Design based in Newport, Rhode Island. He is also a Certified Invasive Manager for the State of Rhode Island Coastal Resources Management Council and a member of the Association of Professional Landscape Designers (APLD).