En EspaŅol

Q. Who is Mr. Smarty Plants?

A: There are those who suspect Wildflower Center volunteers are the culpable and capable culprits. Yet, others think staff members play some, albeit small, role. You can torture us with your plant questions, but we will never reveal the Green Guru's secret identity.

Help us grow by giving to the Plant Database Fund or by becoming a member

Did you know you can access the Native Plant Information Network with your web-enabled smartphone?

Share

Ask Mr. Smarty Plants

Ask Mr. Smarty Plants is a free service provided by the staff and volunteers at the Lady Bird Johnson Wildflower Center.

Search Smarty Plants
    
 
See a list of all Smarty Plants questions
Can't find the answer in our existing FAQs, submit a question to Mr. Smarty Plants.
Need help with plant identification, visit the plant identification page.
 
rate this answer
Not Yet Rated

Tuesday - July 12, 2011

From: Southampton, NJ
Region: Mid-Atlantic
Topic: Pruning, Shrubs
Title: Pruning smooth azalea in NJ
Answered by: Anne Bossart

QUESTION:

I have a Smooth Azalea growing in my woods. It was verified by the Master Gardeners of Burlington County New Jersey. It's 12 feet tall and lanky. Can it be trimmed in hopes of thickening up? If so, any tips on trimming it?

ANSWER:

What a great find!  I am sure the Master gardeners can give you pruning advice as well, but yes, with careful pruning you should be able to sculpt your shrub and thicken it to a degree.

Rhododendron arborescens (Smooth azalea) is a deciduous azalea which means that it can tolerate (and in the north, require) more sun than its evergreen relations.  If it is not flowering well, its lankiness could be as a result of not enough light.  You don't mention how thick your woods are.

If you decide to prune it, there are two things you must remember: never cut back more than one third of the plant in a growing season, and pruning stimulates growth.  The one third rule means that you can cut back all the branches one third or you can prune one third of the branches to the ground.  The pruning stimulates growth rule means that wherever you cut, that is where new growth will appear.  That is why you sometimes see shrubs that have been sheared to a globe or square shape that are green only on the surface of the plant and have crazy shoots sticking out all over.

So examine your plant carefully and before you make each cut, try to picture how the plant will look without that branch and also realize that exactly where you cut it is where the new growth will appear.

Check out this video on YouTube and watch a demonstration of rejuvenation pruning on some large deciduous azaleas.  That is; one year they cut back one thrid of the branches to the ground and new branches grew from ground level, the second they cut another third and the final year they cut out the last third.  This makes the plant seem juvenile again.  Note that the plants they are demonstrating on are growing in an open, sunny area.

I would also recommend David Joyce's book: Pruning and Training Plants.  It is a great reference for doing all sorts of pruning and it has diagrams.  I am a big believer that a picture is worth a thousand words so it will likely be more helpful than my description.

 

From the Image Gallery


Smooth azalea
Rhododendron arborescens

Smooth azalea
Rhododendron arborescens

Smooth azalea
Rhododendron arborescens

More Shrubs Questions

What about the brown dots on my Silver sage?
June 27, 2008 - During the past year, the leaves on my silver sage bushes around the perimeter of the front of my house have turned yellow in places and there are tiny brown dots on virtually all of the leaves. If I ...
view the full question and answer

Need shrubs to plant alongside a swimming pool in Tampa, FL.
September 05, 2011 - I Have a 3 1/2 foot gap between my pool screen and back fence. This gap runs about 30 ft. long. I would like to place small trees to look beautiful and to grow 6-8 ft. high to screen out my neighbor...
view the full question and answer

Enough sun from San Marcos TX
February 22, 2013 - I would like to plant both Lantana urticoides and Salvia farinacea in area that only has morning to 1pm sun..Will this amount of sun be enough?
view the full question and answer

Plant for full sun behind waterfall
March 21, 2009 - I have a 24 inch waterfall around my pool. I need to plant something behind it. I have full sun and hot Texas weather. I will be watering everyday, so what do you think would grow well in this area?
view the full question and answer

Transplanting native flame leaf sumac in Eden, TX
October 26, 2008 - We have tried without success to transplant a flame leaf sumac from the ranch to the house. What are we doing wrong?
view the full question and answer

Support the Wildflower Center by Donating Online or Becoming a Member today.
E-NEWSLETTER | BECOME A MEMBER | DONATE NOW | MEDIA | SITEMAP | STAFF
© 2016 Lady Bird Johnson Wildflower Center