Stormy, first, take a few deep breaths please! First off, there simply is no hard and fast rule about such. True, trees often compete poorly with a heavy turf, and the reverse is true also at times, but that's just the fact of the matter-nothing you do will change the facts. Now, what "look" do you prefer? Wide rings of soil or mulch around your trees? Grass right up to the trunk? The problem with the latter, besides the already-mentioned competition issues, is that people often bang up the trunks of their trees when mowing around them. so from that standpoint alone, a mulch ring or some kind of planting bed is preferable. Sometimes, we do in fact remove all turf in large, old trees experiencing decline issues. This is an attempt to make the soil conditions more forest-like and has shown varying degrees of success. But to jump from there to saying-as one of your sources did-that no turf should share space with trees, is an overboard take on things.

The biggest issue I see in your post is that you apparently added a lot of soil around this magnolia, right? This can be very damaging to trees-to have the grade changed over their roots. so tell us more about what was done please. We may be able to intervene before the tree starts to show its resentment of having that done.

+om

Stormy, did you read my response to your last post regarding this subject in the Landscape Design forum? I hope I explained clearly to you how important it was to keep the additional soil well away from the tree, beginning at the dripline. You should be able to grade the soil so that the transition from the area around the tree, where the soil level should remain unchanged, blends smoothly with the raised soil area of the rest of the garden.

And just so +om knows I didn't give you bad advice (!), I did indicate that you could lay the sod under the tree but to allow a clear area surrounding the trunk that can be mulched to keep weed free and to allow for ease of mowing. You could certainly extend that to create a planting bed surrounding the tree but I got the impression that was not your intent or preference.

Garden Gal, I hope you don’t mind that I asked the opinion of more than one person. Lots of feedback is what makes Garden Web so great! Since this is about a tree, I thought I should at least post one question with our friends on the tree forum. But, I do greatly value your advice! :)

I agree with wisconsitom. The grass issue isn't that crucial. There are all sorts of "rules" about the "right" way to do things...but not all rules are equally important. If you plant grass too close to the tree it will compete with the tree...but that's nothing a mature, healthy tree can't handle. These rules are mostly or people planting baby trees.

There are other things in your post that pose a bigger risk. If you cover the roots with too much dirt, it could suffocate them. If you pile dirt or mulch around that trunk it could make the tree rot. Of course, the biggest threat mature grass poses to a mature tree is the equipment you use to mow it. I recommend you use marker or paint to mark the root line of the tree so you know how deep to bury it. I also recommend you take pictures of the roots, and put a small fence around the tree trunk.

I'd just like to make an overarching statement about the turf/trees interface: Namely, that it is a human introduction, such plants never having lived together in nature. Grasses mostly have the ability to aestivate, ie. go dormant due to drought. Trees have no such mechanism and must continue pumping water all growing season long. They therefore have very different competitive advantages, and that is why, as Ed said, this is mostly a factor in young tree growth. In such situations, the thick web of turf can quite easily outcompete a small, young tree for water/nutrients when the going gets tough. Now take that same tree, blow it up to mature size, and the tables are somewhat reversed. The tree at that point has spread its roots far and wide, it has cast much shade-turf grass species mostly can't handle shade-and it has laid up tons of stored energy in its wood tissues. But in that early game, grass usually wins.

+oM

I think there is a basic question that has not been asked about the 50 year old Magnolia. What was the tree's shape before you started the project I have seen some Magnolias that through out their lives have been trimmed up so the first branches are some distance from the ground. (You can walk up and touch the trunk with out stooping)

I have seen others trees that have been left alone, and you could no more walk up to the trunk than you could fly.

If the shape of the tree was the former you may get grass to grow under the tree, if so as Stated I would leave a 6 to 12 foot diameter ring around the tree. I would mulch it, and plant shade plants.

If its shape is the second you probably can not do anything under the tree with out damaging the tree. If you have all ready trimmed up the tree, it still maybe difficult to grow grass because of the decades of material that has accumulated under the tree.