Noxious weeds can be poisonous or act as an irritant to humans, but not all are directly harmful. However, indirectly, noxious weeds also compete with native species, effectively affecting our local ecosystems of plants, pollinators, and other animals.

The main problem with crabgrass is that it produces thousands of seeds that can remain dormant until the following season. To get rid of it, you have to remove existing plants before they have a chance to spread seeds and stop old seeds from germinating.

You should add 1 to 4 inches of mulch, depending on your garden type and needs. Keep in mind that no amount of mulch can completely prevent weeds, but a heavier coverage (closer to 4 inches) can suppress weeds enough that you are only seeing them sprout every few weeks. Finer mulch prevents weeds more effectively than large mulch, so if you’re using mulched leaves or shredded bark, 1 to 2 inches will likely suffice, while 3 to 4 inches is best for larger mulch, like bark chips or straw.

Landscaping fabric can only help to prevent weed growth in the short term. It's not an ideal long-term solution because dirt will eventually make its way on top of it, causing weeds to sprout. These fabrics can also leave microplastics in the environment for many, many years, so pulling weeds using one of the methods in this guide as soon as you see them is a better long-term prevention strategy.