Mechanical Control methods physically disrupt weed growth. Mechanical weed control is the oldest and most often used method worldwide. Tillage, hoeing, hand pulling, blading, grubbing, cultivation, mulching and mowing are examples of mechanical control.
The Most Commonly Used Mechanical Controls
Tillage works by disturbing the root system. The objective is to dislodge or cut the root system so the plant dies from drying out before it can reestablish its roots. Tillage easily controls small weeds and is most effective in hot, dry weather with dry soils. To effectively control noxious weeds, repeat tillage each time new shoots emerge (about every two weeks) for one or two growing seasons. Make sure you cut off every plant. Tillage can also kill weeds by burying them. Most annual weeds die when all growing points are buried. Burial is not effective on most established noxious weeds since their underground parts will resprout.
Mowing reduces annual weed growth, but will not prevent seed production because most weeds just flower again closer to the ground. This is especially true with Spotted and Diffuse Knapweed. The knapweed plant will adjust to the level of the mower and will go to seed at only a few inches tall.