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My rhododendron loderi is losing leaves and becoming too leggy. #748261
Asked May 05, 2021, 5:36 PM EDT
Multnomah County Oregon
Expert Response
Thank you for your question, Paul. I believe I answered your questions about this plant last year. It really needs to be pruned, but you might want to wait until the blooms are spent. You'll need to prune rather severely, but be sure to leave a growth node near the base of the stems, or nothing will regrow. The plant will look rather sad for a few years, until it has produced new stems and foliage. You probably will get no blooms for a few years. Here is an article on pruning basics.
Did you do a soil test before adding sulfur? You may have added too much or not enough. Here is a list of labs you might want to consult: Analytical Laboratories Serving Oregon | OSU Extension Catalog | Oregon State University
Finally, since rhododendrons have very shallow root systems, they are stressed by not having enough water. Regular watering plus a good mulch which holds it in and keeps the soil cool should help. I hope these plans, over time, will restore your plant to health.
Kris LaMar
This link was not included: https://extension.oregonstate.edu/sites/default/files/documents/12281/pruningtreesshrubs.pdf