“How close should I plant a tree to my house?” is a question I have been getting a lot lately. It makes sense as it is Spring tree planting season. Today I will try to answer this question.
Why would I want to plant a tree close to my house?
There are at least two reasons you would want to plant a tree close to your house. They are aesthetic and energy savings.
Aesthetic reasons to plant a tree close
The main aesthetic reasons to plant a tree close to your house is it just looks better there.
It is because we typically plant trees much smaller then they will ultimately grow. We see the cute little plant we are putting into the ground and think it looks ridiculously small planted thirty feet away from our front door.
Of course we know that trees DO grow. That little oak tree will hopefully eventually grow to look something like the mature ones we see that dot my neighborhood.
But that it will probably be LONG gone before this happens in your yard with a Burr Oak. So instead we plant that tree a lot closer to our house so that it looks good now. Or at least sooner.
It’s understandable. It just looks better 10-20 feet from your house then it does 30-40. Plus you will get some shade on our house sooner, which could result in energy savings.
Energy saving reasons to plant a tree close
The other reason to plant a tree close to your house is to help keep it cool in the summer. This can help you save on your air conditioning costs.
Some guidelines for planting trees for energy savings include:
- Plant large deciduous shade trees on the east, west and southwest sides of the home to shade your house. Avoid planting them south where they block the warming winter sun.
- Shade air conditioning condensers to make them more efficient. Shrubs or a small tree can do this easily.
- Plant trees and shrubs that will act as wind tunnels to direct breezes into the house. Limb the branches up to allow breezes to pass under shade trees.
Shading your house with a tree
The sun is highest and hottest in the early afternoon just after noon. For houses however, this sun typically hits the roof.
To help cool our home’s interiors, we should be shading the late afternoon sun which is coming in at a lower angle and can enter our houses through the windows. This sun also heats ours walls which can then radiate into our homes into the early evening.
The Distance a tree is set from the house will control the amount of shade a tree gives in a certain area.
- Since the sun at noon is is so high in the sky, even a tree 40 -50 feet high will cast a small shadow at this time.
- The same tree, with say a 30-foot spread will cast a shadow equal to the tree height at 3 to 4 p.m. in midsummer.
Therefore in order to get the most useful shade on the house, you should place a shade tree about 20 feet from the house.
Problems from planting a tree too close to your house
If 20 feet will make our 40 feet tree cast the most shade on our house, why couldn’t we also plant one 5 feet from our house for even more shade?
There are 3 main issues that could result from planting a shade tree too close to our house.
- Mechanical damage – roots get near a foundation or utility line, & exert pressure against it. Hence the raised and broken sidewalks we see near some species of tree, such as Norway maples.
- Trees make the soil moisture fluctuate due to taking water up. This can cause problems when soils expand & contract which can stress your foundation by pressure.
- A branch could fall on a house, or the tree could topple.
How wide and deep will the roots extend?
In general, tree roots grow between one and three times the width of the canopy of the tree. This does not mean that you have to freak out all the trees in your yard are reaching out and trying to destroy your house and sidewalks.
The reality is that most of these tree roots will not be that large or strong. These are mostly smaller fibrous root hairs and the smaller roots that support them. There are exceptions though.
Trees with aggressive roots
These trees are probably NOT safe to plant even 20 feet away from your foundation. There are enough other better trees to plant in residential settings, so don’t bother with these.
If you must have them, get them way out there away from foundations, water pipes, septic fields, and sidewalks.
Poplars, Cottonwoods and Aspens (Populus) – nearly all have wide-spreading root systems that desperately seek out water. They are one of the worst to plant near homes.
Silver Maple (Acer saccharinum) – have shallow and dense roots, plant well away from foundations.
Norway Maple (Acer platanoides) – Large, near the surface roots are notorious for raising concrete. There really is no reason to plant this invasive bully when there are so many better trees.
Willows (Salix spp.) – all of the tree’s have extensive root systems which help to anchor willows in their native wet environments. They also run deep looking for moisture. Definitely keep these away from your home, septic and water systems. These trees really don’t belong anywhere near a home.
American Elm (Ulmus americana) – American Elms have deep roots that often clog sewer lines and drains. These should also be kept well away from anything related to water.
Two Others to avoid near your foundation: Black alder (Alnus glutinosa) and Black Locust (Robinia pseudoacacia).
Smaller trees can be planted closer
If you want to plant a tree closer then 20 feet from your house, say 10 feet, it’s best to plant one that has well behaved roots. These include most smaller trees like crabapples and serviceberry as well as most conifers.
Some trees like Japanese maples can be planted as close as a few feet away from a foundation and pose virtually no risk to the foundation.
For more information on some other smaller trees that can be planted closer then 20 feet see my posts on Paperbark and Three-Flower Maples as well as my posts on More smaller shade trees and Smaller understory trees for your yard.