Weed Growth and Control Guide

Weed Growth and Control

Site preparation.

The most frequently overlooked aspect in the area of ​​landscape maintenance is site preparation. Control existing weeds, but especially perennials, before beginning any correction and development. Non-selective translocated herbicides (those that move from the application site to other parts of the plant) that contain the active ingredient glyphosate (such as Roundup ) or glufosinate (such as Leopard or Finale) can be used to kill existing annual grasses and many other types of perennial weeds. Non-selective contact herbicides, including synthetic active ingredients (such as diquat-dibromide) or organic ingredients (such as acetic acid (acetic acid) and clove oil (clove oil)) are effective for the control of young annual plants if when they are well covered with the solution. Soil solarization can be used, but the soil must be covered with clear plastic for four to six weeks. Solarization is effective when done during the time of greatest solar radiation — June through August, in most of California, but also later in some parts of the state.

Annual weed numbers can be reduced by watering the area after final correction, allowing the weeds to sprout. While weeds are small, remove them using a shallow rake (less than an inch deep), scraping them out of the ground, or spraying them with a non-selective post-emergence herbicide and repeat this process of watering, sprouting, and removing two or three more times.  This will greatly reduce competition from annual weeds and their numbers.

Define the type of plantation.

Proper choice of plant types and landscape design can facilitate weed control. For example, installing mowing strips , planters, and flower beds to help reduce weed invasion and outline planting types (Figure 2). Woody plants, especially those that are already established, are more tolerant of most pre-emergence and closely grown herbicides. Consequently, there are more weed control options if the plantation consists entirely of woody plants, compared to herbaceous annuals or perennials or a mixture of all three.

Choosing drip or underground or micro-sprinkler irrigation instead of using rotary or lawn-type sprinkler heads also helps reduce weeds, as the water is placed on or near the plants. Rotor and lawn-type sprinklers are designed to irrigate large areas, such as lawns and playing fields, but in a landscape, there are often larger spaces between plants. In addition to wasting water, this type of irrigation only promotes weed growth.