Question
We've been doing some landscaping in our backyard and have replaced a pear tree that was located too close to where our new retaining wall would go ( in addition to the fact that it had some other problems ) Now that the retaining wall is in we were wondering where to plant our new pear tree. From the the retaining wall to the house is aprox. 26 feet.  We have an existing nectarine tree planted 16 feet from the wall and 13 feet from the north end of the yard. We'd like to keep the fruit trees on that end of the yard. Can we plant it close to the retaining wall(it is only 2 feet high on that end of the yard)or is it best to put it elsewhere? Thank you for any direction you can give!

Answer
Hi Sunny. It really depends on the individual tree for deciding how close to any wall or structure it can be planted. There are also different types of pear trees and the root systems can vary between varieties. (Not a major factor with pears though).
I wish I had a picture of your yard. It can be tough to visualize and take in all factors of practical designing without physically seeing the yard. As a landscaper, we take in everything we can when we walk through a yard.
Generally with trees, the root spread underground is closely equivalent to the canopy/drip zone (outer branch spread above the ground) With that in mind, I usually try to find out the full grown spread of the canopy. Now you should be able to plant far enough away from the wall so the roots never interfere with the structure. This is your way of insurance. Anything inside this area becomes a possible risk. (Especially in cases of severe winds, hurricanes, etc that can uplift a tree and the root system).
I hope this helps you a little? also considering factors are overhead lines, underground lines of gas, water, electric, irrigation etc..
enclosed are a couple of links for you that are related to your question. One on care for pear trees and on on planting and transplanting info. Have a great day Sunny. Kevin

http://www.portkellsnurseries.com/?id=growingpears

http://www.ag.ndsu.edu/horticulture/trees