3

Context. I plan to grow a tall tree on the front yard to achieve a natural look. The surrounding area is limited by walls and powerlines in the ground. So this tall tree better not have its roots expand horizontally too aggressively as it will damage the walls and powerlines. Horizontal expansion of roots must be roughly limited within 2 by 2 meters.

Question. Which trees can grow up to 5 meters tall (at least) such that their roots expand vertically mainly, and not much horizontally?

1
  • I would be amazed if there's a tree that qualifies. Even a mere palm tree (very little vegetation for it's height) cracked our block fence something like 20 years after the neighbors planted it a bit over a meter from the fence. Oct 17 at 1:38
6

Typically, deciduous North American and European trees grow roots 50% beyond their canopy, so a 5 meter tree with a 5 meter wide canopy will require a root run of 7.5 meters, regardless of whether it has deeper roots (like an oak) or not. Conifers are a littler more compact, but any tall conifers will still require much, much more room than a 2 meter wide "flower pot". Even if you were to plant a tall tree in the area you want, the lack of root run will dwarf the tree, as if it were a bonsai, which will stress it and most likely lead to an early death.

It seems to me that you either have to vastly downscale your tree or think 'large, tall, shrub'. For a tree, you could, perhaps, try a fastigiate (columnar) serviceberry (Amelanchier sp.) at 3m x 2m would work. For tall shrubs (technically, small trees but usually sold as shrubs), there are fastigiate arbor vitaes (Thuja occidentalis 'Emerald Green' at just under 3m x 1.5m. for example) or junipers like 'Skyrocket' that could work, but the tallest of those would be no more than 3 meters.

4
  • Any workarounds? E.g. can the roots grow as they want, for as long as they grow underneath structures/wires? E.g. under house's foundation, or under wall's foundation?
    – caveman
    Oct 16 at 23:12
  • I wouldn't worry about roots interfering with buried utilities, although it's important to note that any trenching done by a utility company will kill tree roots and could, if done close enough to the tree's trunk, seriously harm the tree. Most trees won't grow under a house's foundation because it's too deep, but can grow under a shallow wall foundation if there's water and nutrients to be had on the other side. I had a 150 year old silver maple growing 4m from the corner of my 70 year old house's foundation with no affect on it, but the tree had tens of meters of root run elsewhere.
    – Jurp
    Oct 17 at 14:12
  • What if the tree dies. Will the roots underneath the house decay and create a void? Ultimately leading to at least causing the house to tilt?
    – caveman
    Oct 17 at 16:22
  • 1
    It's true that the stumps and upper roots of large trees will cause the ground to sink as they decay, any tree roots that low down in the soil will be much smaller and will cause no problems. The structural roots of trees like oak and buckeye will probably not grow under foundations and if they did, the rotting process down that deep is, if I remember correctly, different because it's anoxic.
    – Jurp
    Oct 18 at 12:14
4

Tree roots grow where they want regardless of what a book says, although there may be preferences. Southern pines, oaks and sweet gum grow roots randomly based on trees cleared from my lot: the dirt man pushed over many with a bulldozer so the roots were visible. I have dug hundreds of smaller trees to transplant and never noticed a particular growth habit. I notice my fig tree has many surface roots. I live in an E. TX rain forest and have not noticed utilities ( buried electric, gas, water, sewer) having problems with tree roots damaging facilities. Southern pines are generally 100 feet tall here.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.