Cotoneaster shrubs are common in modern landscaping and can produce a considerable amount of new growth each year. Cotoneaster hedges can grow well over 10 ft tall so it is important to trim and prune them every year to keep them shaped to the size that you want and prevent them from becoming too large. Cotoneaster can also be affected by Fireblight which can kill parts of the hedge and requires extra pruning.
Plug in your electric hedge trimmer and use it to cut the new growth of the cotoneaster shrub back to the woody old growth. Electric hedge trimmers should be with a controlled sweeping mooting that travels parallel to the surface of the hedge so that it mainly clips off the ends of new growth rather than cutting into the hedge. If you want to allow the shrub to get larger in some areas, do not cut the new growth all the way back to the woody parts of the hedge in those spots.
Use a ladder to reach the new growth on the top of the hedge if necessary.
Remove any dead branches or branches affected with Fireblight by cutting them off as close to the ground or as close to healthy growth as possible using a wood saw. Old dead branches will not have any leaves while branches that are dying or affected with Fireblight will have brownish or yellowish leaves that may be shriveled, which should stick out against all the healthy green leaves.
Use a manual hedge trimmer to clean up the trim job you did with the electric trimmer.
Rake the trimmings into a pile and place them in a leaf bag. If you had to remove dead branches, cut the dead parts into sections so that you can fit them into the leaf bag.