Large lilac tree beside house--risk of foundation damage?

My friend, a new homeowner, just called me with a question: He has a large lilac bush/tree that reaches as high as the peak of his one-story ranch house. It’s very close to the house (a few branches are brushing against the house). His neighbor suggested that he take the tree down, to avoid any damage to his foundation. My friend’s wife likes the lilac where it is.

What’s the dope? Great risk to his foundation? Mild risk? I’m aware of the risks of some types of trees’ roots invading septic and other plumbing lines, and obviously of the danger of roots pushing up sidewalks/driveways from beneath, but hadn’t heard much re: danger to foundation and house (other than from damage to siding from branches, risk of rot/termite/ant contamination from mulch touching the wooden parts of a house, etc.).

I’d guess the lilac tree is about as big as it’s going to get. It’s not like it’s a sequoia, so I imagine the risk to the foundation is small. In any event, if there were damage to the foundation, it’d likely be visible, inside or out. And generally, if the sewer pipes are not on that side of the house, I wouldn’t worry too much about roots. Bottom line? I wouldn’t sweat it, though I would keep an eye on it over time.

How close is this lilac to the house’s foundation? They can damage foundations, but you’d have to have them very close to the house to do that. 5 feet is the minimum suggested distance, i’ve read. The damage they do probably wouldn’t be as bad as planting a pine right up against the house, but my guess is they can cause cracking.

Where does your friend live? The climate is probably going to be the determining factor in whether or not the lilac gets much bigger.

Near Framingham, MA.

Hmmm… this reminds me of a good question – how far away should an Austrian (or was it Australian?) Pine be from a foundation? I don’t want to kill the tree, but if it’s the tree or my basement, then, well, I’ll be merciless.

I can ask one of my mail lists, but why keep the tree anyway? Casuarina equisetifolia (Australian pine), is considered to have no good benefits unless you absolutely cannot get your hands on a better tree, or they’re growing where they’re actually native. The roots are desne, they drop lots of needle like branches, the fruits are like spiny little cones. I’d cut the thing down and plant something else. There’s lots of interesting plants native to Sonora like tree morning glory (Ipomoea arborescens), or Torotes (Bursera microphylla – related to Frankincense and Myrrh and also has odoriferous wood and sap).

On second thought they’re probably not available there, if Querétaro is any indication of nurseries in Mexico (they grow nothing but Jacaranda, Eucalyptus, Italian cypress, and your Australian pine everywhere). But really, Australian pine is pretty much useless except maybe beach locales or where you cannot get any other tree suitable for windbreaks.

Oops! My fault entirely. My house is in Michigan, where I normally live, and that’s where the pine is. It preceded my presense in the house as well, and it looks pretty good there. Need something to fill the massive amount of space that we enjoy in the United States compared to how houses are butted up against each other here!

I think having driven between Phoenix and Kingston not too long ago, I’d like to try to get one of those joshua cactuses to grow here if I weren’t just a renter. That was an interesting looking tree.

As for native trees here, about the only think I ever see is mesquite.

Oh. Well. Either way, I think Australian pines are ugly and you can do much better, even in Michigan! But, if you like it, hey, it’s your tree. How close to the house is it? They tend to root deeply, but they have lots of fine surface roots. The best use for this tree is firewood (it is said they are excellent for that, especially in 3rd world countries). If the tree is close to the house and has lots of surface roots, it may not be a good choice to keep it. Even some big trees can grow close to buildings or roads. I’ve seen Cupressus macrocarpa growing so close to sidewalks that the trunks look like they’ve melted over the sidewalk, but the sidewalk shows no sign of cracking.

Yucca brevifolia is the Joshua Tree, and ranges only in western Arizona. A Similar looking plant found in Mexico is Yucca filifera which i believe is a lot more common.

There is actually more than mesquite. The two I mentioned earlier are native, you just have to know where to look and what they look like :).

Wow! I do have yuccas in front of my house (in Michigan). No, I have no idea how they live through the winter, but they do. I have no idea what kind of yucca it is, but do they all form “trees” like that eventually? Mine’s pretty much at ground level, and I think it’s reproducing at that level – there seem to be a couple of mini-yuccas near it.

Not all Yucca become “trees”. Y. elephantipes does (and is common), but many others stay at ground level, like Y. whipplei (Our Lord’s Candle), native just south of here and Y. rostrata (Bird’s Beak). They’re all quite variable.