mulching trees

I have always had no trouble with letting the grass grow under my trees but the man on ask this old house says to always mulch is okay just letting the grass grow under them.

Mulching to suppress other vegetation reduces competition with the tree's roots for soil moisture and nutrients. This can aid in more rapid establishment of a newly planted tree, and reduce stress on a tree during weather like droughts, etc.

Mulching to suppress other vegetative growth also reduces the likelihood that the tree will suffer damage from vegetation management tools - like mowers and weedeaters - which is one of the biggest reasons for failure of woody plants in managed landscapes.

No one HAS to mulch around trees. Many trees live long full lives with being mulched by humans. Trees also tend to congregate amongst themselves when left to their own devices, and most of the time that is NOT in a manicured lawn environment.

Forests....for very good reasons.

Excellent, sensible advice and observations. :-)

This message was edited Feb 23, 2015 4:50 PM

I never like to use mulch around my trees due to when I use the mower it got thrown everywhere and one time I put a bunch of mulch down and put it to thick and it actually cause more problems even keep my perennials for come up.

Around here the summer is so dry that mulch is a great idea to keep the soil cooler and moist. It also keeps the weeds down, and improves the soil in several ways.

I have a red maple that has a lot of roots coming up through the grass and the trunk has been damaged by the weed whacker so I've decided to mulch around it. My question is, should I put topsoil over the exposed roots at the base of the trunk before covering it with landscape fabric and mulch? You can see in the pictures that the base of the tree is quite a bit higher than the lawn around it. Thanks in advance for any help!

No more soil, no fabric. Just mulch.
The fabric tends to work its way up through the mulch.
The roots are used to being exposed to the air. A coarse enough mulch that does not hold the water too much is good. Soil might exclude oxygen a bit more than the tree would like.

Those pictures are a very good reason that people should think about the future when planting a tree, and set it up for the roots to go deep. Lightly sprinkling the soil with water does not get the water down deep. If the water is only at the surface, that is where the roots will be.
On the other hand, watering deep is very good, but if it is done so frequently that the water excludes oxygen from the deeper zone, then the roots will be at the surface.

This message was edited May 13, 2015 6:11 PM

Hi DomesticLaura:

First, let's properly ID your plant. You have a red-leafed maple, and that species is a Norway Maple (Acer platanoides) - likely a named clone like 'Crimson King'.

You do not need to add soil over roots that have grown to diameters such that they are now exposed. It would be a different story if you were experiencing severe erosion, and soil had been washed away. Maples as a genus form many roots shallowly in the soil profile, and thus as they increase in diameter the "tops" of the roots become visible at the surface. Improper watering practices might exacerbate this characteristic, but the trait comes with the Maple territory regardless.

I would NOT suggest use of landscape fabric, but highly recommend that you mulch around your tree to protect the exposed root surfaces and tree trunk. You won't need mulch up against the trunk, but be generous (2-3 inches thick) with mulching the soil surfaces and places where roots can be damaged.

You should plan to widen the ring of mulch area periodically, as Norway Maple is a densely branched tree casting pretty deep shade, and with characteristically shallow roots it is a vigorous competitor to most lawn grasses.

I'm so glad I asked my question, thank you for the answers and the tree ID! I will lay down some mulch but nothing else. I'm now wondering if I should do the same with another tree that appears to be the same species and was probably planted at the same time. That tree has moss growing under it, mixed with some grass, a few hostas, and some weeds. The roots aren't as shallow and the trunk doesn't have weed whacker damage. Should I still do 2-3" of mulch, or should I leave it as is? Aesthetically the mulch isn't necessary as that portion of the yard is a huge mess (I can just barely keep up with the kudzu, glossy buckthorn, and poison ivy that keep invading from the adjacent woods, but that's another post).

It is always your call about mulching versus not. Just because there currently is no damage...

It is an investment to keep up with, but it never hurts to mulch when applied properly. You can always cease mulching in the future.

Mulch will slow down weeds that grow from seeds. Many weed seeds need to be exposed to light to sprout, or will only grow a short distance before dying. So a couple of inches of mulch is enough to stop this sort.

The invaders you describe, however are not going to let a little mulch stop them. They are going to invade whether there is mulch there or not.

If you did a good clean up under the tree, then mulched it would slow some of the weeds from returning. The Hosta would probably like it, too.

Make sure you don't over mulch. Your tree roots are close to the surface because they need more air than some other trees. A heavy mulch layer reduces the tree's ability to get air and could risk its health. Attached is a pic I found on mtbnj.com of what not to do. Also, if you mulch with something like pine bark, you might spend more up front but you would not have to mulch nearly as often as it breaks down slower than shredded hardwood.

Wow, Sequoia! That is a really good example of how not to mulch!

Yes, keep the soil next to the trunk bare.

Yeah it was quite fun typing 'mulch volcano' into Google and looking at all the images.