I can find plenty of weed and grass killer‘s. I can find plenty of weed killers that won’t kill grass. But grass seed tends to make it into my mulch bed and I want to kill that grass without harming the bushes flowers etc. I cannot find any chemical it says it does that. Does it just not exist?

I think you're asking the wrong question.

The better question is how does the herbicide (aka weed killer) work?

What you're looking for is an herbicide that absorbs through weeds' leaves not their roots. That way as long as you only get the herbicide on weed leaves then your flowers and shrubs are fine.

There are going to be 2 classes of herbicides for grasses:

Non-selective - kills everything. The last few decades that product has glyphosphate and nearly all of it absorbs through leaves not roots. This year Bonide came out with an organic product called Deadweed brew that uses 2 acids.

Selective - only kills grasses. That's a much smaller number of products and usually marketed towards farmers or hunters (i.e. they grow food plots for hunting). Hunters who grow clover, alfalfa, etc. want to kill the grasses so they don't compete so they use a product like Arrest max

Herbicides can also be classified by when they kill:

Pre-emergent - prevent the grass from growing there. Preen would be an example of this.

Post-emergent - kills something that already grew. The previously mentioned glyphosphate, Deadweed brew, and Arrest Max are examples of this.

What I do is sprinkle the mulched landscape area (flowers and shrubs only. Don't do following on vegetables/fruits) with preen, and once or twice a year carefully spray anything it misses with glyphosphate. I live in the south and have St. Augustine grass which is much more aggressive than northern grasses like kentucky blue grass or fescue.

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Ego is the anesthesia that deadens the pain of stupidity

DISCLAIMER: These are the author's own personal views and do not represent the views of the author's employer.

IF you can't spray without hitting out foliage then use a paint brush with round up.

How deep is your mulch bed? Does it have a fabric weed barrier underneath? Does it have a barrier around the edges?

I have a large flower bed, which I keep mulched to 2-3 inches deep or so. It has a weed barrier under the mulch, as well as metal edging. I rarely have more than a stray tuft or two of unwanted plants at a time, which I just pull by hand.

If you have significant grass growing in your mulch bed, it sounds like you need deeper mulch, or a more effective barrier under/around it.

^^^ Pretty much what tatortodd says plus there are selective weed killers that will kill weeds (technically a weed is anything you don't want) or rather broadleaf weeds and not kill grasses.

Basically a "Roundup type" that kills everything or a Broadleaf killer that you can put on grass to kill dandelions and similar but it won't kill grassy weeds like crabgrass or similar.

What you need is a pre-emergent that is applied and keeps them from starting.

quote:

Originally posted by Skins2881:
IF you can't spray without hitting out foliage then use a paint brush with round up.

Another option is there are guards for pump sprayers. For example, my new 1-gallon Chapin Stand 'N Spray Sprayer comes with this:

There is a product called Preen that prevents the seeds from germinating. Won’t harm plants, just the seeds. It’s a granulated product.

quote:

Originally posted by Sigfest:
There is a product called Preen that prevents the seeds from germinating. Won’t harm plants, just the seeds. It’s a granulated product.

Yup. All my mulch beds get Preen works pretty well needs to be reapplied every couple of months though.

Tatortodd has it right, what he left out was the use of pre-emergent herbicides to kill newly-sprouted grasses and annuals. This has to be done carefully to avoid harm to any annuals later planted in the beds, but should have little affect on established plants. Pre-emergents, as the name suggests have to be applied before you see the weed, and after application should not be disturbed, e.g. by cultivation, as they act as kind of a barrier to new shoots.

If the weeds are already well-established, it's Roundup or similar. This, as noted above, is sprayed on the foliage and some weeks later kills the whole plant. Beware of wind drift during application as some desirable plants are very sensitive and a tiny exposure will wipe them out. But at least Roundup doesn't poison the soil like some of the older "total" herbicides do. The last time I looked at HD, it appears that Ortho, et. al. are now delivering products that contain a number of herbicides, most formulations combined with Roundup. I would be very careful using these products, test on a small area, etc. before general application.

Consult your county extension agent, they will be up on the latest "best practices," and their advice is already paid for by your taxes. Consider hiring a professional, but if you do, check their certifications and liability insurance.

quote:

Originally posted by architect:
Tatortodd has it right, what he left out was the use of pre-emergent herbicides to kill newly-sprouted grasses and annuals.

You should've read the whole post...