Question
Hi,
I planted three Sequoias about five feet from my pool. Am I asking for trouble? Thanks.

Answer
It depends. Sequoia have a fibrous root system the can  spread about 2-3 times the width of the foliage. All trees will seek water and if there is a water leak from the pool the roots will grow seeking the water and could damage the pool. Also depends on the type of pool--cement or  liner. The cement type will be less prone to leaks and is a better barrier for the roots then the liner type. These trees are very slow growing so the problem IF there is one will be many years down the road. You can also keep the trees pruned to a smaller size reducing the root system. You can install a root barrier between the trees and the pool this will deflect the roots away from the pool. Here is a web link to these barriers. http://www.4specs.com/s/32/32-9452.html

I think the main problem will be the dropping of the needles into the pool. Sequoia tend to drop needles throughout the growing season and being this close can get into the pool.
  
Since they are planted I would enjoy the for now and try to keep them pruned to a size that fits the area. Years do the road you may get tired of the needles and the size may over grow the planted site and then you can decide If they need to be replaced.e