You can safely plant a tree or shrub in an area where Glyphosate was used without any serious plant injury. If rain is expected within eight hours of application, wait until a dry period occurs because the effectiveness of Glyphosate is greatly reduced by rain. Dacthal and Surflan are both similar in action and both give good control of weeds. They will not, however, control any weed that is already growing. Hand weeding of annual and perennial weeds is often practical especially where there are few weeds in a small area.
Herbicides are only substitutes for hand labor and are only as effective when properly applied.
Preemergence weed killers are normally applied in November and June, just prior to the rainy seasons. If however, you decide to convert your lawn at another time of the year, treat the area with the preemergence at this time and again in November and June. If you plan on planting seed of African Daisy or California Poppy, these chemicals will prevent their establishment. After the first year full control is usually achieved. Roundup is used at a diluted rate of 6 tablespoons per gallon of water.