My husband planted a holly bush in the fenced in area of our swimming pool about 10 years ago. It is now about 10 feet tall and 8 feet in diameter. I am worried that the roots will start to invade and crack the gunite in the pool as it is planted about 8 feet from the edge of the pool. Is this a reality or just my imagination? If you think that I should move the holly bush ( or is it a tree? it really is very lush and bushy) when would be the best time of the year to do so?