How to expand a grassy mulch bed under Kwanzan cherry tree

[j-nova]

Hi everyone,

I have a large Kwanzan cherry tree in my front yard and have been informed that I should expand the mulch bed to the drip line of the tree. The current mulch bed goes about 2 feet from the trunk, and the drip line is about 12 feet, so I have a long way to go.

I have grass all around the tree, and I even have an exposed root from the tree in one spot, so I want to be careful in how I do this. I've seen other posts about how to kill off the grass, but my understanding is the cherry has shallow roots and I need to be pretty careful.

Can I trim down the grass real short and do the wet newspaper layer + mulch? If I do that, is it ok to cover up the exposed root of the tree with the mulch as well? I would assume so, since the issue is that it just needs oxygen right?

 

[Jason Douglas]

My method for killing grass under a tree:
Mark the border first then spade the edge.

String trim the hell out off the grass. Down to the soil and turf crowns.

In a few day, the grass will start to grow again. Spray with vinegar and surfactant. Be mindful of avoiding surface roots.

In a few days, you can put down your mulch.

If grass survives and pops through the new mulch, now you can use Roundup as surface roots will now be covered with mulch.

Yes this is time consuming but you'll avoid pitential glyphosate toxicity this way.

 

[ATH]

I'd do similar except skip the vinegar step...just put mulch on the injured grass and kill what comes through.