How to banish grass from flower beds, conclusion
Johnson also recommended selective herbicides such as Ornamec, which can be applied broadly to some plants to kill grass.
The label should indicate whether a selective herbicide is safe for your garden.
If you are extremely careful, you can also use a non-selective herbicide for patching.
“To treat the grass growing close to the garden plants, put on rubber gloves first and then an inexpensive cotton glove,” Johnson instructed.
“Using two fingers on the cotton glove, dip in the herbicide and gently wipe the grass blades, avoiding drips on adjacent garden plants.”
If you wait until the dead of summer, it will be difficult to kill grass with herbicides: the products work best when the grass is actively growing and can lose their effectiveness in the heat.