How do i get my forsythia bushes to thicken up?

they are 7'to 8' tall, have been in the ground for 4 years


i have never cut them.

How do i get my forsythia bushes to thicken up?
Right after they bloom is the time to prune these spring flowering plants.I like them best when they are not sheared. Cut off old and crossing branches and that will generate some newer lower growth. For me a pruning book with some pictures that show you exactly how to make the cuts is helpful.They say to take about three years to do a gradual reduction of old growth. They are pretty tough plants, so doing a fairly good pruning this year probably won't kill it. Then just do a bit each spring after they have finished their blooming.
Reply:cut it right back after blooming and for a few months after that. then leave it to make the flower buds for the next spring, do same next year
Reply:CUT THEM BACK HARD