Answer: If there are many weeds in the planting bed then you have a choice. You can spray them with an herbicide containing glyphosate, or you can physically remove them, or you can trim them off short and smother them under a layer of newspaper.
If you use the herbicide, read and follow all of the label directions. This is a contact herbicide and will kill your trees or shrubs if it contacts them, so be very careful when you apply it.
Depending on the product you use, there may be a waiting period before it becomes fully effective. Wait that time, then remove the killed foliage and stems, before mulching. It is important to allow adequate time for the herbicide to translocate through the plant to the roots where it actually kills the weed.
To physically remove the weeds, pull them out or dig them out. Be sure to take the root as well as the stem and leaves. If the weeds are very small, they can be hoed off at the soil surface. Immediately cover with a layer of organic mulch several inches thick.
To smother the weeds, mow or cut them off very short at ground level and cover with layers of damp newspaper. Cover the paper with several inches of organic mulch.
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