We have a row of very mature Pieris along a narrow walkway They are over 5 feet tall even after we recently trimmed off the new growth. These bushes have just grown too big for the space. They get regular water during the summer with full sun. How far can we cut them back and or thin out, and still have them put out new growth?
Thanks for your question and the photos.
It appears your plant is a Pieris japanica which can grow to 12 feet tall. Consequently, to keep then below 5 feet will require major pruning every year. Compact forms are available.
You can prune to limit height, but don't just cut off the top growth.
- First, cut out all dead and dying material.
- Remove any branches that cross over the center.
- Remove any branches that rub against other branches.
- Lastly, shape the shrub into a natural form.
To guide you, two publications from the Oregon State University Extension are attached. The first, "Pruning to keep ornamental shrubs healthy" can be viewed at this link: http://extension.oregonstate.edu/gardening/prune-keep-ornamental-shrubs-healthy
The second, "Pruning Trees and Shrubs" can be seen at: http://extension.oregonstate.edu/mg/metro/sites/default/files/Pruning_trees___shrubs.pdf