Mulching mature trees?

[whitenack]

I have some mature trees in my back yard that I want to mulch.

They have never been mulched before, and I was wondering the best way to go about it.

I know I should only put a thin layer down, as to not suffocate the roots, but I was wondering if I should dig up the grass before I put the mulch down, or just put the mulch down on top of the grass.

Thanks,

 

[Redbull]

Personally, I remove the turf first. Just be careful not to damage any roots in the process. Here's some pics of a younger tree that I mulched.

 

[Kneejerk Bombas]

The problem with removing grass is that tree roots are very shallow. Over 90% of tree roots are in the top 12" of soil. If you remove 2" of soil and grass, you've also removed over 15% of the tree's roots in that area.
My favorite method is to mow the grass as short as your mower will go, or even weed whip it right down to the soil, then cover the area with newspaper, and compost, then chip. Total added compost and mulch should never exceed a 3" depth, and should not touch the trunk.
The newspaper keeps the grass from growing and then decays away into compost. Wood chips can have the effect of absorbing nitrogen and can create a slight deficiency until the chips start to decompose, so that's why I like a layer of compost below the fresh wood chips, to make up for that slight nitrogen sink.

To critique RedBull, he took away too much soil and tree roots, he plunged his shovel deep enough to cut any root that was out there, the tree is planted too deep (he should have replanted it while he had a shovel in his hand and was cutting roots off anyway), and his time would have been better spent fixing the co-dominant stems.
Other than that, it sure look nice.

 

[Redbull]

Mike, you're right, the tree was planted too deep. This tree was here a few years before I started caring for it. Question though, would I have been able to replant a tree that size by myself? It is about 3.5"D, which seems like a good size tree to be digging up and moving. How far out from the base would I be safe to dig? Also, I was very careful when removing the turf so as not to cut any tree roots. I think the pic might be a little deceiving. The turf was Zoysia (very thick), and I removed maybe 1.5"-2" of soil when I pulled it up. I just rolled it like sod. The reason I did this was because the tree was planted too deep from the get go, and I wanted to expose the root flare. The co-dom. stems were pruned after these pics were taken. Mike, I value your opinion greatly and appreciate you feedback.

 

[Big Woody]

landscape fabric

Is there any problem with putting landscape fabric under the inch or two of mulch to keep grass or weeds from growing up through the mulch? Seems it should be OK but someone told my wife it was not good.

 

[Kneejerk Bombas]

Trees like a lot of decying organic matter in the soil. Much of this normally comes from litter that falls, lays on the surface and decomposes. More of it comes from roots of plants that grow and die, grass for example, will lose about 50% of its roots each year, and annual grass loses 100% of them. Growing 6 to 8 inches deep, you can see these roots can add significant amount of organic matter over time.
Landscape fabric creates an impenetrable barrier for this organic matter to reach the soil, it just builds up on top. In time the weeds will grow right on top anyway. What's more worrisome is this build up will eventually bury roots too deep to get what they need, oxygen, water, and organic matter.
If the area of fabric is small compared to the root zone, then its not such a big deal.

 

[whitenack]

Another thought I had:

I live on a cattle farm. In the winter, we feed the cattle hay in the same spot year after year. Over time, a mixture of mud, hay and manure is built up around these sites.

Would this stuff be good for anything?

 

[pmuscato]

Whitenack, sounds like an excellent organic mulch, use it. And Mike is right stay away from Landscape fabrics they do more harm then good. IMO