Thanks for the explanation Laag. When I've referred to "bark mulch", I included all mulch that originated from trees and did not realize that there was a distinction between the wood and the bark in the mulch universe. I suspect that I am not alone. I recall someone telling me some years ago that mulch (without distinguishing between "wood" and "bark") should not be used near wood structures (e.g., porches) because it invites termites. I never did know if there was any truth to that. Back to the use of plastic--food for thought for the OP: I have 1-foot wide area between a fence and a walkway that I can do little with because of it's size and location. Tired of killing weeds, wanting to be able to simply ignore that area, and knowing I will never plant anything in that area, about 5 or 6 years ago, I leveled the soil so that it sat slightly below the adjacent walkway and laid down 3 mil plastic (secured with landscaping pins) and covered with several inches of mulch (don't know what kind, whatever the dark mulch that is commonly sold at gas stations). I have never had a problem with run off in that area and I must say, the weed control in that spot has been tremendous. Other than getting rid of an occassional weed and replenishing the mulch now and then, the area has been maintenance free for the most part.

We have mostly oak trees and tulip poplar trees. Even if I shred them with my leaf vac or lawn mower they remain a blonde shade of brown. Not really my cup of tea for more formal front beds. I use them in the backyard since it has a more naturalist look and it is so thickly planted once spring comes I can't see the mulch anymore. BUT... our county collects leaves in the fall and they offer shredded leaves mulch for free. I am guessing they are right in the middle of decomposing because of the smell and heat but they are black. I went to the leaf deposit site with an armful of garbage bags and got enough mulch for the front beds. I don't think they will last more than a year but since they are free I am ok with having to redo it annually. Question: how deep should shredded leaves be for weed suppression? 2 inches, 3 inches?

I concur with the above about your poor burned cedars. If you can water them, slowly, deeply and widely, over the summer, whenever the ground dries out in the top 2-4", and maybe mulch around them, it will help counter the stress and aid the re-growing process. Maybe next year, or even this summer, when you notice the grasses in the ditch getting to the danger point, you can trim them back with a weed eater - maybe even before, so there is no critical mass of flammable material? Another fire may well kill the trees. I think moving any trees out of a row so closely planted and so mature will only result in the death of the ones left, if the ones moved don't die also. It's just possible that some will survive, but after 33 years, their roots will be so intertwined and maybe even grown together, that they will all, those moved and those left, suffering from major shock. With careful watering for the next 2 years, at the least, careful mulching and a lot of luck you might get away with it. Refilling the holes PROMPTLY with a good quality soil would also be necessary. AND you will have the problem that the trees will have self-pruned on the sides facing the other trees in the line, and may never branch out well on those sides when standing in the open. I really think you would be better to thin them, cutting down every other one or so, or at a minimum, taking the weaker ones, leaving the 2 end ones, as they will have green growth on their outsides. You would still have to contend with the problem of branch growth into the new space, but the disturbance to the roots would be a lot less, especially if you only cut the "extras" off at ground level and then left them alone.

I'm not knowledgeable in any way, but I don't think it would be worth it to remove all the mulch you already put down. I'm betting that the cedar mulch helps to repel insects that might live in the soil, like earwigs and centipedes. Most butterflies spend their time up on the plants rather than on the ground. You may limit the number of butts or moths that burrow, but only in the areas that you mulched. Hopefully some one more informed than me will respond. It is an interesting question. Welcome to the world of butterflies. Need any seeds? Martha