Deadheading Rhododendrons

Seeing the fantastic Spring blossoms on Rhododendrons, brings up the next question, to deadhead or not to deadhead?

And probably then, what is deadheading?

We’ve been noticing a large number of blossoms on Rhododendrons around western Pennsylvania this Spring, thinking that they are having a banner year! Those flower buds are set during the previous year’s growing season, and probably benefitted from that rainy start to last summer, as they were ‘setting their buds.’

In my early days as a nurseryman, when I was still learning both ends of a digging shovel, so to speak, I became especially enamored with Rhododendrons, enough so, that I joined The American Rhododendron Society and purchased the book on Rhodies authored by Ted Van Veen, “Rhododendrons in America” which has since been donated to the library.

I was telling my first mentor, Walter, who was a retired coal miner turned nurseryman, how much I liked the Rhododendrons with yellow blossoms. In his basic, age old wisdom, from planting and maintaining high- end landscapes in posh neighborhoods, he said, “Bob, how many yellow Rhododendrons do you see growing in gardens around here?” My answer was a very simple, “None.”

Walter, who grew mostly Taxus evergreens, (commonly known as Yews) went on with his Yoda- like wisdom, asking, “What color Rhododendrons do you see growing here most?” My answer then, and to this day, is “Purple.” Usually the light purple ones.

That being said, we have a red one, a Nova zembla, next to our front porch. There used to be two of them, and the remaining one is only a small remnant of the broadleaf evergreen it used to be, yet it is just now, beginning to open up about 15 blossoms, on its few remaining branches. It’s always a special May event, seeing those gorgeous flowers, with their fine detail, and snapping photos to send to our daughter, while remembering that she spared it from being ripped-out, during one of our many front yard landscape renovations, over the past 38 years.

Rhododendrons join Azaleas in being a bit contrary, when it comes to getting them established and growing well, due to some inherent insect and disease problems, as well as being very site specific. They won’t tolerate “wet feet” from heavy soil and poor drainage, prefer an acidic soil pH, and would much rather live on the east side, right next to a building with morning sun, than in a more exposed or blistering hot southern exposure, where solar panels would thrive.

So it never fails, that you will see some of the older, established Rhododendrons, light purple of course, ten feet tall and often wider, crowding the side of a house or garage. Native Rhododendrons, with their larger leaves, later bloom time, and pale pink- white flowers, thrive in the understory of Pennsylvania forests.

Back to the term “deadheading.” That’s the basic term for removing spent flower blossoms. The old debate with Rhododendrons, was whether or not that added maintenance step, strengthened this broadleaf evergreen. Last I recall, university research indicated it did not make that much of a difference in this broadleaf evergreen’s vigor, but the one true benefit, in any case, is that it improves its appearance through the rest of the year.

In this short video from 2011, I demonstrate how to deadhead a Rhododendron:

The one additional piece of advice, besides taking in their Spring beauty, up close, is to deadhead them before new growth gets a head start, since there’s more room to work. Then you can decide if the extra effort was worth it, on your Rhododendrons.