Weeds with which type of leaf surface are more difficult to kill?

Weeds with a hairy leaf surface are more difficult to kill because the hairs can serve as a protective barrier, hindering the absorption of herbicides. The presence of these hairs can diminish the effectiveness of chemicals by causing them to be repelled or absorbed less effectively, leading to suboptimal control of the weed. Additionally, the hairs may trap air and moisture, which can further impede herbicide uptake.

In contrast, plants with smooth leaf surfaces often allow for better contact with herbicides, promoting more effective penetration into the leaf tissue. Leaves with a thin cuticle might also facilitate herbicide absorption, while broad leaf surfaces do not inherently present a barrier to chemical uptake in the same way that hairs do. Therefore, the presence of a hairy leaf surface is a significant factor that complicates the spraying and effectiveness of herbicides in controlling those particular weed species.