Controlling Weeds                                           

Weeds can make ornamental plantings look unsightly. Weeds also may harbor insects and diseases that may cause problems on more desirable ornamental plants. 

The weeds will  also compete for light or use water and nutrients that ornamental plants could use for growth.         

Successful weed control depends on preventive methods, proper weed identification, and the timely use of cultivation or chemicals.

Prevention

Mulching is the easiest way to prevent weed problems in your landscape (See Mulching and Using Organic Mulches).  These materials shade out weed seeds located under the mulch and also prevent the weed seeds on top of the mulch from making contact with the soil. Mulching will not solve all your weed problems but will make life a lot easier.    

Pre-emergence herbicides are another option for preventing weeds in the landscape. Products like Preen®, and weed preventing products, keep seeds from germinating and growing. They do not effect existing weeds, so you must apply these products before you have weeds, either in the early spring or right after you've cleaned up a bed. 

Post-emergent, non-selective herbicides can be used effectively to control established weeds. Round Up® and Finale® are two of the common brands on the market. These products  do not differentiate between weeds and ornamental plants. If they are applied improperly, they can injure ornamentals.  The most serious problems occur if you use them when it's windy. If the wind is blowing and the spray drifts, these chemicals will injure the trees and shrubs. These products are systemic and travel through the plant and dill the top and the roots, making them very effective against perennial weeds. For tough weeds more than one application may be necessary. The products mentioned leave no residual in the soil. The weeds will die in one to two weeks and you can plant or sow seeds in the same location.   

When trying to control existing weeds in established planting, direct the spray at close range to individual weeds. It only takes a drop or two to kill the weeds. Another option is apply these products with a sponge or paint bush. Use gloves when doing this and again be careful only to apply the material to the weeds.

Products that are designed and sold to control existing broadleaf weeds in lawns, should no be used in planting beds. Care should also be taken not to let lawn weed control products drift onto planting beds.