Q&A: How do I prune a low laying pine?
A. I'm not sure the type of pine you have, but the method of containing growth on pines is quite simple.
In the spring you will see new growth taking place on the ends of the branches. This new growth, commonly called 'the candles,' should be cut back with a sharp pair of pruning shears when they are about three or four inches long. Prune them back two-thirds or down to one inch. This slows the growth of your pine and you should be able to keep your pine to a reasonable size for a number of years. Cut the candles before they start to open, otherwise it will be too late.
John Craw, Master Gardener