sidewalk strip landscaping around tree with raised roots

[yubafarm]

Hello, I have a strip of ugly weeds between the sidewalk and street that is about 30' long and 6' wide. For the outer 10' sections, I am going to dig out the top ~4" of weeds/roots/soil,then sheet mulch with compost/cardboard/compost/mulch with ground cover and stepping stones. I am probably going to put some concrete scalloped edging around the perimeter so that the depth of mulch can be deeper and to keep stuff from blowing around.

For the middle 10' of the total 30' length I don't know what to do. There is a mature carob tree with roots that are 10" higher than the sidewalk right near the trunk, tapering down to 3-6" above the sidewalk for 5' in each direction from the trunk. The entire raised area around the roots are covered in weeds that are impossible to pull up. here is that nasty grass that grows by rhisomes and is impossible to dig up or get rid of. I know I shouldn't put mulch within 12" of the trunk. how can I keep weeds down around the tree? T Can I spray the weeds with vinegar to at least kill them first? Otherwise they will come right through the mulch. I don't use pesticides or herbicides, but have fantasized about using roundup to get rid of these weeds. Someone please stop me!

I can plant a ground cover but it will be infested with weeds in no time. I could put down a weed block fabric but have mixed feelings about that and don't know how close to the trunk it should go. Have thought about a weed block fabric then compost/soil on top, with ground cover seeds planted in it, with jute fabric on top to hold it in place for these areas that are higher than the sidewalk as the ground cover gets established, then I could put mulch on top of the jute. Worried that the roots might not breathe well under the fabric and also worried that I made up this idea and not sure it will work. This will be a lot of work for me and I'd like to get it right the first time.

I appreciate your advice! I am in Oakland CA, a temperate climate and headed into the dry season.

 

[patandchickens]

IME you are never, ever, no matter what, going to get rid of that grass if it is a perennial, without hurting the tree. Well, MAYBE with careful repeated painting on of Roundup, but certainly not through any other means. Because it will be all underneath the roots (where yo cannot pull its rhizones up) and woven into the roots' "bark", with so much underground stuff that some will survive no matter how vigorously you go at it.

Vinegar will likely not kill the grass (of course I don't know what kind you have, but, most kinds that could be described as you're describing it will laugh off vinegar, the foliage may wither and die but it'll just sprout right back again, over and over) and too much *repeated* vinegar application may not be good for the tree.

So my suggestion for that would be to learn to like the stuff and call it part of your lanscaping. Perhaps add some Very Large Decorative Rocks (not everywhere). If you were very very lucky you might be able to find something that can at least "hold its own" with the grass, not necessarily outcompete it but at least mix in with it so it looks better; but note that things like that are often rampantly invasive in their own right, and you may not want to send the spider in to catch the fly, and then the mouse to catch the spider, and the cat to catch the mouse...

You could TRY smothering it out with one or two thicknesses of carpeting, removed once or twice a season to pull out the grass that has started to grow into the structure of the carpeting; but that is pretty likely to be bad for the tree (I don't know about carob trees in particular) and would take years to work if it were going to, and then chances are one little piece will come back and you'll be back where you were.

Or, if you have spare time, just plan on ripping up as much of it by hand as you can, every weekend til the end of time. This is not actually such an unreasonable plan, and as time goes by less and less of it will grow back. But you do have to do it VERY REGULARLY or you're right back where you started only with a lotta wasted effort

For the rest of the boulevard strip, rather than digging it all out (which is likely to be Bad for the carob tree, plus lotsa work) why not just fit a piece of discarded carpeting onto it, upside-down, and cover that with mulch for a few years? Unless you want to plant in it *now*.

Also, btw, if you are going to put raised edging around the boulevard strip, make sure your city bylaws permit it; a lot of places would not let you do that (tripping hazard)

Good luck, have fun,

Pat

 

[yubafarm]

Hi Pat, thank you so much for the advice. You confirmed a lot of what I've been thinking: leave with the weeds around the tree as I'll never get rid of them, but perhaps beautify them if possible. Makes sense.

The reason I wanted to dig up the rest of the strip (away from the tree) is that if I don't, the mulch will end up several inches above the sidewalk and it won't stay in place. I've also worried about the trip hazard of using the edging to hold the mulch in place. I've seen others do it but don't know if it's legal. If I avoid the parts near the tree I could get away without any edging. I was thinking that I wouldn't find many surface roots from the tree in these areas, if I do I won't dig. Do you think this could still be bad for the tree?
thanks again,
Colleen