There are several weeds that any gardener has to know and treat in order to prevent them from developing.
Ragweed is a common plant that causes allergy reactions. In its blooming period the ragweed can be dangerous. It is very common in sunny locations and needs to be treated with chemicals.
Mushrooms are another plant that could be dangerous, but there is nothing which could prevent them from growth. They won’t hurt your lawn, but don’t eat them, because some of them might be toxic.
Clover is often seen at the lawns in early spring. Its produces puffy flowers and actually these flowers can damage your grass. In order to get rid of the clover, you need to spray the grass with herbicide; the best in this case is triclopyr in the fall.
The ground Ivy is a flowering weed that usually spreads very quickly. It is also perhaps the only weed that doesn’t respond on herbicides, so you need to remove the creeping stems of the plant. The best time to get rid of the ground Ivy on your lawn is to control it when it first begins to flower. Overall, spray you lawn with herbicide once in a month to prevent bad weed growth.