|do I have to spray some weed killer before putting down the mulch? if so what kind of weeds control should I buy for the flower shrub beds.|
|It is a good idea to pull and/or hoe off short any existing weeds before you spread the mulch. If you have quite a few weeds, you could layer some damp newspaper on top of the soil and then put the mulch on top of that. (It excludes light and prevents most weeds from growing.) Organic mulches and the paper will eventually break down and help feed the soil.
When you mulch, spread it out several inches thick in a flat layer over the root area. Do not allow it to touch the stems. Fluff the mulch periodically and top it up as needed to maintain a layer two to three inches deep. This helps prevent weeds from germinating in the mulch layer.
If you also wish to use a pre-emergent weed preventer product, please read and carefully follow the label directions on that product.