Bald Cypress Knees Threatening Foundation: Root Barriers or Removal?

The Problem

A 20-ft Bald Cypress planted 10–15 ft from a house in a low, wet area is sending up "knees" (aerial roots) toward the foundation. Oklahoma City's wet year exacerbated it. Roots can spread 45–60 ft; knees form in saturated soil to access oxygen.

Options

1. Root barrier: Install a vertical HDPE or geotextile barrier along the foundation to deflect roots.
2. Remove the tree: If roots already threaten the foundation, this is the only permanent fix. Treat the stump with concentrated glyphosate (Roundup) painted on the fresh cut to prevent root sprouts.

Key Points

• Knees won't regrow if cut, but new ones form if soil stays wet.
• Cypress roots seek water—leaky pipes, drains, wet yards attract them.
• Roundup on the stump translocates to roots, killing the system. Use a brush to avoid drift.

Given the proximity (13 ft to foundation) and active knee formation, removal + herbicide is the safest long-term choice.