Hi & welcome to Gardenweb! Happened to click on this yesterday, an idea that might work for you. You just need to be SURE that's where you want it.

Hi! I can actually see a line defining the strip in front of those rocks! For what it's worth, I personally don't think the grass is so bad leading up to the rock border... probably just a pain to break out the trimmer every time you mow, though, huh?!

If you want a space between the grass and rock edge, though, I would first recommend using an edger/trencher (not sure what to call it) it cuts down into the soil (not across like a trimmer) so that you can easily sever the grass roots and dig up the unwanted strip of sod layer. I just borrowed my friend's last week, the deepest setting on it is 1.5" so it's really not that big of an undertaking. But it does create a "trench" which greatly deters the grass.

Then, I'd sprinkle some Preen on that strip every 3 months or so during the growing season to keep the grass/weeds at bay.

I don't think I would plant anything in that strip in front of the rocks as you will always be struggling to keep the grass out. But if you really want to, maybe a nice ground cover would work for you, like Thyme or Sweet Woodruff. I personally like the stone edge and would prefer it not being obstructed.

I hope this helps you... I'm slowly edging out all my beds this year b/c of the grass encroachment, too... so this is where my brain is currently! And I have to say, even just leaving the beds with a trench around the perimeters (since I haven't laid the mulch yet) - the beds look SO beautiful being so defined! :)

I put up some pics and info in another thread yesterday that might be helpful here also.

Flowergirl, although I've never used any, my understanding of preen is that is for the prevention of seeds sprouting. If your grass is invading via seeds sprouting, you may just need to mow more often, before the grass can make more seeds, and make sure the chute is shooting into the yard, not the bed. Once you have established an edge you can maintain, the grass will have an extremely hard time getting back into beds. A functional barrier does not need to be chemically maintained. A trench is not a permanent solution, unless you enjoy re-digging it periodically.

If the grass is invading through rhizomes/stolons, the preen will not do anything to it, and you wouldn't want it to because it could kill the entire "chain" of grass connected to the poisoned piece.

HTH you save $ and use the products more effectively. There are very specific instructions on the labels of chemical products. Using them other than directed is technically illegal, usually ineffective, and can be a waste of time and $.

to purpleinopp- I knew I was putting myself out there by mentioning Preen since it is a chemical. But I do want to say that I DO read all labels before applying, so please don't assume that I don't... to imply I'm doing something illegal is just ridiculous and quite frankly irritating to read on what should be a friendly garden forum. Also, just because I use Preen doesn't mean I'm all about chemicals, either... so please don't be a hater.

I would hope that anyone who is considering buying Preen will read the directions for themselves and decide if it's right for them. It was just a suggestion given to gstump, who can take it or leave it...

Gstump, I apologize if you find my suggestion as awful as purpleinopp apparently did- but despite what this person says, I'm just sharing with you things that have worked for me and my garden, which is what this forum is all about.

Lastly, I never said the trenching would be a permanent solution (I doubt "permanent solution" is a term that even exists in gardening!) but it's a good jumping off point (at least has been for me) and it does help immensely with the fight against grass growing into unwanted areas.

Sorry you got caught in all this gstump! :)

Flowergirl, I apologize that my intention, to help you, was not made clear in my message. I assure you, I'm not a hater, far from it. Look around a bit, I think you'll see. I most sincerely hope you will not consider me an enemy, nothing could be farther from the truth.

Chemicals have their place. My Mom is not capable of maintaining her yard without them and I don't have time to pull all of her weeds. I don't begrudge her methods even if they are not identical to mine. However, using chemicals to maintain what could be a functional border need not be necessary for anyone. I reiterate this opinion because I feel strongly about it, not against anything anyone said.

May not be the case for everyone who reads it, but your description of your use of preen: "...sprinkle some Preen on that strip every 3 months or so during the growing season to keep the grass/weeds at bay", left the incorrect impression with me at least, that one can control the edge of grass with this product.

If what I said about trenching not being permanent felt like I had put words in your mouth, I apologize for that also. My intention was to simply finish what you said about it. "But it does create a "trench" which greatly deters the grass." Deter does not equal prevent.

If you are happy with your current situation, it is the perfect solution for you. Pointing out what I think are more long-lasting and easier to maintain alternatives are not a dig at you, just an attempt to enlighten you if interested, or others who may read.

Did you have a chance to look at the pics, my (I hope) new friend?

purpleinopp- Hi- glad to hear you're not a hater :) Your pics are very nice! While those applications would not work for us in our yard, hopefully gstump got some good ideas! thanks for sharing :)

yes, FYI to fellow readers: Preen only prevents weed seed/grass seed from germinating- if they have germinated though, Preen will be ineffective.

I, also, don't believe Preen would prevent grass by runners, but will prevent seed sprouts like those from ornamental grasses and annual grasses like crab, etc.

gstump: We have multiple, curvy, mulched beds outlining our property, but no formal (or informal) edging other than "where the mulch starts" and "where the grass (is supposed to) end" so it was a never-ending, overwhelming, and losing battle until I started trenching. I trenched the front of our yard 2 years ago and have been so pleased, I'm finally getting to doing it to our backyard!

To purpleinopp's point, trenching is not for everyone! However, aside from the initial labor (of love), trenching for me has proved long-lasting, easy to maintain, and pleasing to the eye!