Flower beds: weed prevention and when to plant flowers
To reduce weeding maintenance put soil sterilants into the soil about three weeks before planting. Just before or in a short time after planting, apply a pre-emergent herbicide and leave it undisturbed on the surface. (But read before about plant sensitivity to various herbicides.)
Other methods of weed prevention on flower beds include the use of a physical barrier such as black plastic which you may covered with a thin layer of decorative mulch. Check whether you punched numerous holes in the plastic to ensure adequate water supply and penetration.
Most spring flowers can’t be planted until the danger of killing frost has passed. Many warm season plants, such as periwinkles and caladiums, cannot tolerate cold soil temperatures, so you need to wait and delay planting until the medium temperature reaches 70 F.
Shed any plants that may have re-sowed themselves from last season. They’ll be less healthy and may differ from their hybrid parents. If it is impossible for you to plant right away, keep plants in a lightly shaded spot and do not forget to water them as needed. If possible, it is best to plant on a cloudy day or late in the day to reduce transplanting shock.