I'm strange in that I don't worry too much about trees and foundations. If I see a problem starting I have no problem cutting a root, taking down a tree, or cutting patio slab. I'm considering cutting a hole in our wide driveway and planting a tree. That's where I'm coming from.

I do know the patio slab is not connected to the slab your house is on. And also, unless there is some leak someplace, the soil under your patio and house is probably bone dry. I don't see why a tree would send roots under there and if they did, why the roots would get big. No juice, no roots.

So, to me, 9' away is plenty. Branches hitting the roof will be an issue but pruning can handle that.

Thanks Waterbug! I'm thinking I'm going to go for forward with this spot. I do have a second question which I'm going to post but I may as well leave it here too.

I dug the planting hole about two feet deep (for starters) to test the drainage. I filled it with water about one foot deep yesterday afternoon. This morning the water is pretty much exactly at the same level! In other words, I think there's NO drainage. How deep do I need to dig to assure the roots will be able to anchor in downward? If there is a caliche or clay layer, how deep might it be? Some of my neighbors have really tall trees and I'm assuming their backyards have the same drainage issues that mine does. Again, Thanks for all your help.

Mesquite can send a tap root down something like 190' at least for one tree some university dug up to see.

Caliche can be anywhere say in the 1' to 10' range and be thin to foot or two thick. In general caliche is not a continuous unbroken surface. I would never worry about caliche unless it's a known issue. Let the tree earn its keep and let it find the cracks it can send roots through.

It's kind of like the drainage issue...if there's standing water the tree won't grow roots in that area and keep roots higher. As long as we're not talking about a bog the tree will probably find a way.

A lot of these rules for planting stuff are the absolute best possible environment. But plants, like people, can handle a less than perfect world. I may have mentioned in another thread, this year I grew Mesquites from seed in a bucket with no drainage, watered everyday, so it was sitting in water. If you asked a 100 gardeners 99.9 of them would say that's impossible. Most of what you hear is just repeated from person to person, there's little actual testing or knowledge. A bit of common sense goes a long way when listening to advice.

My two cents: I have three Chilean mesquites that are 10 years old. The area from one side of the canopy to the other is an average of 60 feet - yep 30 feet out from the tree trunk. We haven't given these trees a lot of water, and they are not in a grass lawn, this is just how they grow. If I was you, I'd be just as concerned about where all those branches are going to go once the tree gets some size. You risk roof damage if the branches brush the roof or if they fall on the roof. IMHO planting as close as you're describing to the house in going to be a pain in the rear to keep the branches off the house.

Regarding drainage - you may find that the problem is a layer of concrete waste that is buried in the soil. It's not uncommon for builders in these area to do a lousy job with clean-up leaving all sorts of surprises for gardeners to deal with later. Once you dig down another foot or so and get into native soil your drainage may improve.

Our developer planted 2 mesquite trees in our front yard with another tree between them, not sure what the middle tree is. The Mesquite are about 5 feet from the center tree and I’m concerned they are too close. I’ve heard bad things about mesquite trees and I’m not sure what type of mesquite we have. Any suggestions on how to keep them from overwhelming our front yard?

That's a lot of trees. How big is your front yard? Most mesquite get a very large canopy, as stated by crista above. They are also very messy trees. Can you post a picture of how it looks now? This board has been really quiet lately, not sure how much feedback you will get but I'll help if i can. I have two mesquites in my very large back yard.

Well, I'm back nine years after my last comment. Planting the mesquite five feet from the center tree is ridiculous! That would mean they are 10 feet apart, if I'm interpreting this correctly, with another tree in the middle. You are absolutely right - they are too close! You're going to have an overgrown mess in just a year or so. Please replant these trees farther apart ASAP before they get settled. There is really no way they won't overwhelm your yard, and each other, in addition to completely blocking a view of your house from the street if you don't take some sort of action by moving them. They become huge trees. Even if you lion tail trim them they're way to close to each other! Good for you, noticing this problem!

Thank you Crista. My thoughts exactly. I looked on the internet and the mesquite tree gets tall and wide. The tree planted between the two mesquites is a Mulga tree.

The center tree is a Mulga and the two on either side are Mesquite

Oh boy! One tree is plenty for your yard! I'm not familiar with mulgas. Perhaps someone else could jump in. IMHO even one mesquite tree would be too large for your yard. We have one that is 30 feet from our house and we still have to trim it to keep it off the roof. The other thing to consider, is to make sure that no tree is planted near water lines. The roots will eventually crimp the pipes and cause leaks.