Sorry for the slow response. These questions can't be answered with a simple response. There is a great deal of complexity in the landscape and lawn areas and it is important to identify the types of weeds to be controlled before the best control methods can be provided.

However, in general, all herbicides are safe when used according to label directions. Weeds found growing in planting beds will require special care in selection and application of herbicides. Many weeds are broadleaf weeds growing along broadleaf ornamental plants. There are not any broadleaf weed killers selective enough to use near desirable plants without the potential for damage. Spot spraying, hand application, or the use of special formulations may be needed in these situations. Even natural or organic formulations must be used cautiously around desirable plants to avoid damage. Of course, hand removal is the safest method of removing weeds. 

If grassy weeds are growing in broadleaf ornamentals, there are some potential grass weed killers that can be used to control the grass safely around broadleaf ornamentals. Products containing fusilade or sethoxydim are selective grass killers that you might be able to use. Be sure to read the labels of these products to make sure it is safe to use around the ornamental plants you are growing.

Application of herbicides in lawns must also be done carefully. Not all lawn herbicides can be used on all species of turfgrasses so it is important to know your turfgrass species and select the right herbicide for the types of weeds to be controlled. There is also pre-emergent and post-emergent herbicides. A program of both pre- and post-emergent herbicides can often provide better control of some weeds.

The most common post-emergent products are designed to kill broadleaf weeds and most contain combinations of active ingredients such as 2,4-D, MCPP, and dicamba or other related ingredients which make them more effective in weed control. Grassy weeds like crabgrass can be controlled with products typically with the active ingredient of quinclorac, which can also provide control of some broadleaf weeds. 

Herbicide products with iron HEDTA (FeHEDTA) that recently came on the market are organically acceptable products believed to have minimal human health or environmental effects. They are considered safe to control some broadleaf weeds and not harm turfgrasses. Other organic herbicide products are available but most are non-selective, meaning they will kill both grassy and broadleaf plants.

In all cases, be sure to read and follow label directions. 

For additional assistance you can contact the Tulsa County OSU Extension Center.

4116 East 15th Street
Tulsa, Oklahoma 74112
Monday - Friday: 8 a.m. - 4:30 p.m.
Phone: <personal data hidden>

https://extension.okstate.edu/county/tulsa/horticulture.html

Find fact sheets on lawn landscape management at our OSU Publications site - https://extension.okstate.edu/fact-sheets/index.html.