Question
We live in a part of northern California where redwoods grow well. Trees
planted within the last ten years in public parkways are already huge towering
lush trees.

Our neighbors just planted a line of redwoods about a foot away from a
common fence. We are concerned that we will lose the use of the garden area
on our side of the fence.

What is the root zone of a redwood. With lateral root zones, are they larger
than other conifers? What can we do to lessen the impact on our small yard?

Answer
Height: 60 to 120 feet spread: 25 to 35 feet.  The root system is composed of shallow, wide-spreading lateral roots. The roots will have a width of 1 1/2 times the foliage width. There are dwarf varieties that will grow much smaller and the roots spread will be about half this width. Some of the notable dwarf varieties include: Kelly抯 Prostrata (low spreading form) Cantab (Beautiful full growing semi-dwarf form) and Albo-spica (dwarf upright with white tips).

The main impact will be the shade. This is not a good tree for a small yard and a foot from the fence will be a problem with the limbs hitting the fence. This is entirely too close to the fence--5-10 feet away would be a normal distance. Any limbs on your side of the fence can be pruned to the line which will make the tree lopsided. The roots on your side can be cut along the fence to keep them from spreading that way but you will still have the shade problem later. You can spray a herbicide along the fence to keep down weeds and unwanted root invasion. A Root barrier can be installed along the fence these will divert the roots away from your property. These are dug into the ground about 18-24 inches deep and the roots will turn back when they grown to the barrier. Here is a web site for these barriers. http://www.4specs.com/s/32/32-9452.html

I would lean toward trenching along the fence and keeping the roots out by annual trenching and spraying Roundup on the exposed roots when they enter my land.