Rhododendrons

Rhododendron vulcan

To be a gardener in the Northwest means you have dealt with Rhododendrons at some point. It is the state flower of Washington, so you know they are everywhere.

Unfortunately, many of us have rhodies planted right in front of our windows. Perhaps like me, you bought an older house and needed to figure out what to do with all those misplaced rhodies.

When I bought my 1930s house in the early 90s, the main landscape plant was Rhododendrons. Some were probably 50 years old or older. Several had been planted close together in one long row and had grown into each other. Others were standing alone but were very large. I could tell some were special, and the person who planted them probably knew something about plants. I addressed each one as an individual plant to see what could be done, even if it meant removal.

Rhododendron ‘Sir Charles Lemon’

Making Decisions

Fortunately, Rhododendrons (even older plants) have a fairly small root ball, so they’re easy to work with. A few Rhododendron rex in our front yard were very tall, about 15 feet, so I cleaned out the deadwood in the center and arborized them to show off the beautiful bark. They looked great as small trees.

Some were rather spindly, so I cut them back hoping they would grow back, and they did. A few I gave to a friend, and I moved a few to other parts of the garden. When I was done, I had about two thirds of the original plants, but they looked like they belonged there, and the garden still felt like an old garden.

Rhododendron pachysanthum

Learning to Love Rhodies

I didn’t like Rhododendrons at first because many of the cultivars were cultivated for the flower color, so most of the plants looked alike with mid- green leaves, oval, and mounding.

When I started to work at the Miller Botanical Garden, I gained a whole new appreciation for the Rhododendron. There I got to see a whole range of Rhododendrons, many of them species I had never seen before. A big collector of the genus, Mrs. Miller grew many of the Rhododendrons in the garden for almost 50 years. She thought they needed to pull their weight in the garden and needed more than just one season of interest.

My very first job at the Miller Garden was to help deadhead a rather large Rhododendron loderi right by the road. I appreciated how it had been arborized to accent the beautiful trunk, and its fragrance was a nice bonus. I also fell in love with the big leaves of Rhododendron macabeanum and Rhododendron sinogrande. Those large leaves gave the plant year-round interest.

Rhododendron quinquefolium

I wasn’t familiar with the deciduous rhododendrons, so Rhododendron quinquefolium and Rhododendron schlippenbachii became my new favorites. I especially liked the pale green of the new growth of Rhododendron quinquefolium lined with a red band. Both also had excellent fall color. Then there was Rhododendron strigilosum, always the first to bloom with the most brilliant red color.

With dozens of different species and cultivars, it was hard to find ones I didn’t like but with my preference for plants to have more interesting foliage, I was drawn to the Rhododendrons with good indumentum, which is a layer of fine hairs that cover the top or bottom or both sides of the leaf. A few good selections of these were Rhododendron ‘Sir Charles Lemon’, Rhododendron pachysanthum, and Rhododendron campanulatum ssp. aeruginosum. These selections made you want to pet them, in fact many people did. Some of the plants close to the path would have the indumentum rubbed off them from people touching them.

Rhododendron impeditum

Choosing Rhodies for Home

When I bought my current garden about 10 years ago, I was able to put all these lessons to work. I planted Rhododendron impeditum as a small shrub along the borders, and I planted a Rhododendron ‘Sir Charles Lemon’ so that it would be back-lit at sunset, showcasing its beautiful indumentum.

I also incorporated Rhododendron pachysanthum along the long border so people can appreciate the indumentum, and yes, pet it. I bought one big leaf species each year from Chimicum Woods or the Rhododendron Species Botanical Garden at the NHS plant sale and planted it as a stand-alone specimen plant. I added Rhododendron quinquefolium and Rhododendron schlippenbachii in sunnier spots for good fall color. I also moved a couple big specimen plants to the back of the border. I even planted Rhododendron sinogrande in a container that I drag in and out of the greenhouse just so I can enjoy the spectacular foliage. (It isn’t hardy enough for my location.)

Now all I need to get is the Rhododendron campanulatum ssp. aeruginosum for its beautiful blue foliage, and I’ll be set—until the next NHS plant sale.