Rhododendron Pruning: Now that was Easy!

With the peak Rhododendron season of this year just behind us, it is the ideal time to deadhead and do any pruning, especially heavy pruning, that needs to be done on the Rhodies in your yard. Read on to learn about Rhody pruning and the term "adventitious buds," then use the term to prove to friends and neighbors just how much of a green thumb you really have.

Before picture of a Rhody needing some pruning

Many varieties of Rhodies can grow too large for the space allotted to them. If too much time goes by without action some of these varieties will eat up your yard, taking up valuable landscaping space. Because Rhodies will begin setting their buds for next year, a little extra time now can keep these guys under control and encourage heavy flowering next spring.




Follow my 3 Easy Steps:

1)  Start by taking a pair of loppers and reduce the height by taking the tallest branches and cutting them down low in the plant. Once you get the tallest ones out you can always go a bit further by cutting back additional branches, but always remember to step back every few cuts and take a look from different angles so you end up with a balanced plant that doesn't look too crazy.

2) Next, with either your favorite pair of small hand pruners or with just your thumb and forefinger pinch off all the spent flower remnants that remain on the plant. I strongly recommend this step for all your Rhodies each year even if you don't need to reduce the size of your plant as described in Step 1. Leaving the spent flowers allows the plant to expend energy into making seeds and reproducing. We would rather have the plant spend energy making more flower buds for next year. Note: This step can be sticky.


3) Lastly, stand back, take a look, then fine tune the shape and size of the plant by making any additional smaller cuts on a branch here or there by using your small hand pruners to cut back any additional branches that just need to go. For a cleaner look you can make these cuts just above a whorl of leaves along the stem.





Adventitious Buds

Alright, now to the adventitious buds I promised to talk about and an important part of understanding Rhododendron pruning.  Adventitious buds can be described as new buds that break out along the stem where branches and leaves didn't exist before. These develop from particular cells laid down along the stems or branches where they lay waiting just under the bark for the right conditions to break forth. In Rhodies we trigger these adventitious buds to break forth when we cut back larger, woody stems and branches.

Heading cut made to force adventitious bud break

In other words, by cutting back large overgrown branches in the spring, we can force from near these cuts new, young, tender growth to break out and replace the old overgrown areas. It is actually incredible to watch Rhodies and other plants do this.  Many times I will head back a large branch, cutting it half or two thirds of the way down (as opposed to all the way to the base) because I want new growth to break at that point and rejuvenate the plant in that area.  

After picture of Rhody after 3 Easy Steps

Here is a finished look at the Rhody I started with above. From a few feet away it doesn't look like I did anything to it, but compared to the before picture it is smaller, lower, and cleaned up.

This is just what your looking for here, a nice natural looking pruning job, highlighting the plants natural form, but keeping everything under control and flowering well.

Plant Profile: PGM Rhododendron

PGM Rhododendren, Seattle, WA LDS Temple

The PGM Rhododendron is an early flowering, compact, broadleaf evergreen shrub.  I love this plant for its loud profusion of lavender flowers and fragrant scent. To me it smells like some sort of a bubble gum from my childhood.

It likes slightly acidic, organically rich soil which is moist, but not too wet and does well in the shade. 

The PGM is one of the earliest flowering not only Rhody's but spring shrub. It explodes with brilliance in April and, in the Puget Sound, vigorously beckons in spring earlier than spring wants to be beckoned.

Design uses could be as a broadleaf evergreen screen for year round green or as a spring focal point. I recommend planting the PGM in close enough proximity to patios and walkways where the flowers and fragrance can be enjoyed up close and personal. This little guy can certainly stand alone, but if so repeat it in several other places throughout the yard for balance and repetition. In the right area it could also be used as an informal, loose hedge as is done on the grounds of the Seattle LDS Temple in Bellevue, WA. There it is used to create a ring hedge around a circle of lawn resulting in a perfect outdoor room.