Cypress Knee at House Foundation: Immediate and Long-Term Fix

Immediate

Cut knee at soil level.
Paint cut immediately with concentrated glyphosate (Roundup). Kills connected root segment.

Glyphosate translocates locally—may not kill all roots under patio. Watch for new knees; treat same way. May take a spring to clear.

Consider 24″ deep root barrier along foundation if knees persist. But single knee treatment often suffices.

Trees: Killing Bald Cypress Knees with Herbicide: What to Expect; Cypress Knees Under a House: Removal and Management; Can You Remove Bald Cypress Knees Without Killing the Tree?; Bald Cypress Knees at Foundation: Root Barrier Solution; Controlling Weeds and Cypress Knees Around a Lakefront Cypress; Cypress Knees in the Lawn: Cut, Grind, or Mulch?; Bald Cypress Knees vs. Roots: Identification and Management; Eliminating Cypress Knees Without Killing the Tree; Managing Cypress Knees in Tight Spaces; Removing Cypress Knees Without Killing the Tree

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