I have a rhododendrum bush that is at least 35 years old. i have noticed over the past few years that the blooms are less and that the leaves have gotten progressively smaller. I have the bush on the northewast side of my home, sheltered in a corner away from winds in the winter time. Please tell me what is the lifespan of this type of plant? 40 year? 50 years? more? It has been beautiful over the past 10 years or so, but has gradually diminished in size and blooms. What is the solution?
Though some heirloom Rhododendron have been know to live 100 years, their are many factors that go into the life expectancy of a shrub in the home landscape.
Environment conditions, soil, nutrients, disease and pests can all play a part in the health of a plant.
These links will help refresh you on the care requirements.