Pyracantha, or firethorn, is an evergreen shrub hardy in USDA zones 6 through 9. It adds brightly colored berries to the landscape during the cooler months and flowers at other times. It grows rapidly and requires frequent trimming.
Decide to grow the pyracantha as a hedge or an espalier
While the espalier requires a support, the plant also does well as a hedge. For the espalier, trim branches that do not conform to the pattern. When growing pyracantha as a hedge, pruning should begin late in the first season after you plant it or before buds form after the dormant period. Remove approximately half the plant during this pruning and during the pruning for the second growing season.
Shape the hedge
During the third growing season, begin pruning the hedges to the desired shape. Continue this process until the plants mature to a full hedge.
Maintain the hedge
Once established, prune to maintain the general shape, usually two to three times during the growing season. While trimming in the dormant season does not hurt the hedge, it affects the number of berries the pyracantha produces. For the greatest show of berries, leave as much of the last year's growth as possible. Trim overgrown pyracantha as needed, as it responds well to heavy pruning.