Water Collecting in River Birch Crotches: No Need to Drill Drain Holes

Those Water-Filled Crotches in Your River Birch Are Normal

Multi-trunk 'Heritage' river birches often develop depressions where trunks meet, collecting rainwater. While it may look concerning, these pockets rarely cause rot or harm the tree. The bark in these areas is adapted to periodic moisture.

When to Act

If water stands for several days in summer, mosquitoes may breed. Simply drop a Bacillus thuringiensis israelensis (Bti) mosquito dunk (available at nurseries) into the water. It's safe for wildlife and lasts 30 days.

What NOT to Do

Never drill a drain hole. This creates an entry point for decay fungi, insects, and disease, causing far more damage than the standing water ever would.

Bottom Line

Leave the tree alone. River birches are adapted to wet conditions—their natural habitat includes floodplains and stream banks. A little pooled water is business as usual.