Declaring War on Weeds

Walking around outside I can see many lawns that are quite nice and yet are tarnished by weeds. Sporadically located straggly weeds can ruin the beauty of an otherwise nice looking lawn. Or maybe there is a whole patch of weeds where turf is desired. Either way, weeds are not desirable and will out-compete your grass if not kept in check. Weeds can also be viewed as indicators of other underlying issues with soil or environmental conditions that need attention. The simplest definition of a weed is "a plant out of place". By this definition, a typically desirable plant like St. Augustine grass could be considered a weed if it is located in the middle of a predominately Zoysiagrass lawn. Weeds are typically very tough plants that can grow well in adverse conditions such as drought, very little soil (cracks in the concrete), poor soil quality, extreme heat, etc. This is what makes weeds so darn pesky. There are several ways to prevent and combat weeds. The best way to manage weeds is to prevent them before they can even sprout by maintaining a thick and healthy lawn. When weeds do pop up there are several options depending on the type of weed your are dealing with and the time of year.

Know Your Enemy

Weeds come in many types, shapes, and sizes. They are either warm season or cool season and can be broken down into three groups: the broadleaves, the grasses, and the sedges. Within these broad groupings, weeds can be either  annual - growing for one season and dying, biannual - growing for two seasons and dying, or perennial, growing for three seasons or more,. These groupings will help determine what methods of control and what herbicides should be used. 

A Healthy Plentiful Army is Crucial

Your army is your lawn and the more healthy and full it is, the less weeds you will have. Therefore weed control begins with the selection of a turfgrass species that is suitable to its growing environment and proper turf management practices. Proper fertilization, pest management, watering, soil drainage, and mowing will be key in keeping your army of turfgrass ready for battle. A full and healthy lawn shades the soil preventing light from reaching weed seed and causing them to germinate. In addition, thicker grass does not allow much space for weed competition. 

Weapons of War

Although not very appealing, in smaller areas, hand weeding can be a very effective method of controlling weeds. When hand weeding, it is necessary to remove root and other underground portions of the plant otherwise it may grow back. For certain annual weeds, simply mowing them off before they go to seed can be an effective form of maintenance. This type of control will not be effective in most scenarios. In relatively small areas where you are trying to remove entire patches of weeds, smothering with a tarp can be an effective option. When necessary, herbicides can be quite effective if used properly. Herbicides are categorized as either post-emergent or pre-emergent.  Pre-emergent herbicides are used to kill weeds while they are germinating before they can arise from the soil. Therefore they must be applied before the weed can even be seen. This means applying them in early spring for summer annuals, and late summer/early fall for winter annuals. Post-emergence herbicides are applied after the weeds have emerged from the soil. They can be taken up by the weed through the leaves or the roots. Herbicides are also considered either selective or non-selective, meaning that it may kill everything it comes in contact with (non-selective) or it may only kill certain species (selective). The most well known herbicide on the market is probably Round-Up which is a non-selective herbicide that kills everything it comes in contact with. This type of herbicide therefore is not very suitable where there is turf intermingled with weeds. Selective herbicides are needed to eradicate weeds from within the lawn and different types of weeds require different herbicides. Whenever using an herbicide or pesticide always read and follow the label, damage to turf as well as bodily injury can occur if they are handled incorrectly. There is a plethora of resources available online on this topic, I highly recommend looking into them. Here is a useful resource geared towards weed control in southern lawns.