How to Kill Willow Saplings Near Water

Basal Bark Treatments

• Willows have good susceptibility to herbicides applied to their trunks. Use low ester products mixed with oil to saturate the lower 12 to 18 inches of the trunk. Begin applying herbicides in early spring and repeat until mid-fall if the tree does not die before then. Herbicides containing dicamba, Imazapyr, Triclopyr or Dichlorprop (also called 2,4-DP) are most effective, but check product labels for proper, legal use and timing for repeat application.

Foliage Treatments

• If the trees are under 15 feet tall, a foliar herbicide may be effective. Spray the canopy with any quality commercial herbicide formulated for foliar applications and follow label directions. Be especially mindful of wind conditions to avoid spray drifting to nearby desirable plants or into the water. Do not drench the foliage. Check the product label for application instructions and timing, as some sprays work best in summer and some in the fall. Herbicides containing 2,4-D, glyphosate, dicamba and other chemicals work well on willow trees.

Cut Surface Treatments

• If the willow tree trunk is more than 5 inches in diameter, make downward cuts all around the trunk and pour herbicide into the wounds. Leave the chips on the trunk when you cut, to form a cup for the herbicide. Use Picloram plus 2,4-D, dicamba, Imazapyr or Triclopyr. Injection applications are similar to cut bark applications, but require the use of a specialized injection tool. Treat small saplings at chest height for best results. Follow label directions for proper herbicide application.

Non-Chemical Treatments

• To eliminate the danger of polluting the water with herbicides, try girdling the trees. Cut the bark off the trunk in a band 2 to 3 inches wide, completely encircling (girdling) the trunk. The band should be close to the base of the tree. Scrape away the green tissue under the peeled area until you reach the xylem, or inner wood, of the tree. This process cuts off the flow of nutrients to the canopy. It may take until next spring for the willow sapling to die completely.

  Another method is to cut the tree down two weeks after new leaves appear in spring. Drill holes in the stump and fill the holes with saltpeter, or have the stump ground down to below the soil.