Georgia Garden Girl

Ladies and gentlemen, sharpen your clippers.  It’s time to prune in Zone 8.  Before you go to your yard and start whacking, make sure you know what needs to be pruned, what doesn’t need to be pruned, and the basics of how to prune.

The most common pruning question I get relates to the crape myrtle.  People ask, “I see that lots of people cut their crape myrtles way back.  Do I have to do that?”  I say, “Heck no!”  Horticultural experts and master gardeners refer to the practice of hacking off the top of a crape myrtle as “crape murder.”  Southern Living even has a contest to find the worst perpetrators because Steve Bender (aka SL’s Grumpy Gardener) reckons that the “best way to stop crepe murder is to humiliate the criminals by posting photos of their heinous acts on The Grumpy Gardener” website.  If you will promise to refrain from crape murder, I will promise not stop my car to take a picture of your landscaping and post it on the internet for all the world to ridicule.  Plus, you will not waste your valuable time on unnecessary work.

First things first, though.  I should start by explaining why to prune, when to prune, and how to prune.  Then I’ll address specific plants, including the crape myrtle.  Before I sat down to write this post, I thought it would be easy to condense this topic into an article of reasonable length.  Ha!  There are hundreds of books and articles about pruning.  I checked several books out of my local library and browsed a few others at a local bookstore, and I reviewed dozens of articles.  I was happy to discover that these sources are all very repetitive, which I suppose is good—everyone agrees on the basics.  I also realized that sometimes a drawing or picture really helps.  Given that I have removed most of the “pruning nightmare” plants from my yard, I don’t have many great examples that I can photograph, so I need to point you to someone else’s photos.  And if I tried to draw pictures it would take me so long that it would be autumn before I could publish the post, and autumn is generally not a good time to prune, so I need to point you to someone else’s drawings.  For these reasons, I decided to try to put together a clearinghouse of information, which is mostly from the following trusted sources: UGA Extension Service, Clemson Extension Service, Walter Reeves, Southern Living, Pruning Trees, Shrubs & Vines by Karan Davis Cutler (a publication of the Brooklyn Botanic Garden), Gardening in the South by Don Hastings, and Georgia Master Gardener Handbook.

Why to Prune
Safety First.  Let’s say you’ve got a tree whose branches are unhealthy and loom precariously over your neighbor’s garage.  Prune!  Or a tree whose branches are tied up in the power lines.  Call the power company and ask it to prune (then call a line-certified tree guy when the power company says “that’s not our line”)!  Or a bush that blocks your view of the road from your driveway.  Prune!  Or a bush that invades your neighbor’s property year after year (yes, neighbor, I’m talking about that cherry laurel and privet you let creep under the fence into my vegetable garden).  Prune!

Prune for Health.  For any woody plant from a tree to a shrub, you need to get rid of damaged and dead wood.  Leaving it may promote disease.  If you do have a plant with a disease problem, make sure you sterilize your pruning tools between cuts.  Just dip the blades in rubbing alcohol or a weak bleach solution (one part bleach, ten parts water).  Remove suckers, which are sprouts that come up from the base of the tree or shrub.  Suckers only take nutrients and water away from your plant.  For trees, there are a few other guidelines for good health.  Remove branches that grow inward, branches that grow straight down, branches that cross each other, and branches that rub other branches.  Over time, branches that are permitted to rub together will wound each other and may even affect the trunk of your tree.

Keep Plants In Their Place.  I’m going to preface this one by stating what should be obvious.  If you want a small bush, plant a bush that stays small.  Why plant a Natchez crape myrtle, which will grow 20-30 feet tall, when what you really want is a bush that tops out at six feet?  Plant a Dwarf Snow instead.  And why plant a Burford holly that really wants to be 15 feet tall in front of your windows that are three feet off the ground?  If you want to be able to see out of your windows, plant a dwarf cultivar instead.  You can save a lot of time and energy by simply choosing the right plant for the site.

That said, if you’ve made some bad plant decisions or inherited some plants need to be constrained and you are reluctant to remove them, Prune!  You might even get to prune monthly!  (See above regarding Burford holly vs. windows.)  Remember, if you’re trying to constrain a plant, it’s best not to wait until the plant is already tremendous.  If you have a plant that has outgrown its space and you don’t want to do a single “ground level prune,” then you may need to work in phases so the plant will have a chance to recover—never remove more than 1/3 of the healthy growth during a growing season.  And you should know that some plants won’t recover from a severe pruning (sometimes euphemistically called “renewal pruning”)—don’t try this with boxwoods, junipers, pines, cedar, arborvitae, or yews.

Shape Up.
Whether you want a unicorn-shaped boxwood, an espaliered fig tree, or just a tidy looking row of dwarf yaupons, you’ll need to do some pruning.  I like a natural look, so I usually just try to follow the plant’s shape and take out any wacky rogue branches.  I don’t have a great spot for espaliering, so I’m not the best resource.  Visit http://www.caes.uga.edu/publications/pubDetail.cfm?pk_id=7656#Specialty to get started.  I haven’t got the patience for topiary, so you’ll need to do some independent research to achieve that unicorn.  Check out http://www.hort.cornell.edu/livingsculpture/topiary/index.htm for some basic information and resources on topiary.

Get Productive.
You can affect the productivity of your plants by pruning.  With roses, for example, if you want a lot of smaller flowers, prune lightly.  If you want a few large flowers, prune heavily.  Remember, pruning promotes vegetative growth and may delay the production of flowers and fruits.

When to Prune
The “when” of pruning depends on your hardiness zone and on the plant.  Now, you can remove dead wood any time.  But for other types of pruning, there is a “best” time to prune.  Here in Zone 8, we try not to prune our shrubs and trees during the late fall or early winter because pruning promotes new growth that may be damaged by a freeze.  We prune non-flowering shrubs, including hedges, in late winter or early spring.  And we typically follow the “May Rule” of pruning for flowering shrubs.  Under the “May Rule,” we prune spring-flowering plants that bloom before May after they bloom, and we prune summer-flowering plants that bloom in May or later in late February or early March.  So prune your azaleas, dogwoods, flowering cherries, forsythia, and winter daphne after they bloom.  Also, if you have hydrangeas that bloom only on old growth, prune them after flowering (I realize that hydrangeas bloom during after May, but this is an exception to the rule; old-school hydrangeas only bloom on the previous season’s growth.  If you’ve got Endless Summer or another newer cultivar that blooms on new wood, prune away in February).  On the other hand, prune your roses, gardenias, crape myrtles, tea olives, and camellias in the late winter, before spring growth begins.

Totally confused?  Walter Reeves developed a super helpful chart designed to help you decide when to prune each type of plant.  Check it out.  http://www.walterreeves.com/uploads/WRshrubprunning.pdf or http://www.walterreeves.com/landscaping/shrub-pruning-calendar/.  See also http://www.caes.uga.edu/publications/pubDetail.cfm?pk_id=6098#Time.  Another helpful resource: the Grumpy Gardener’s list of 10 Plants You Should Never Prune in Fall (Azalea; Flowering cherry, peach, plum, pear, crabapple; Forsythia; Lilac; Loropetalum; Oakleaf hydrangea; Rhododendron; Saucer or star magnolia; Spirea; Viburnum).

How to Prune
Mama had a professional horticulturist come out to her house to show her how to prune her shrubs.  He told her that she should “prune like a ballerina.”  I’m pretty sure he did not mean for her to put on a tutu and tiara.  What he meant is that for most plants, you need to follow the shape of the plant, and you should proceed gently.

First, make sure you have the equipment you will need.  Most of us need hand pruners and lopping shears.  Those of us who want to prune trees may also find it helpful to have a pole pruner.  And those of us who want to prune hedges will need some hedge shears.  For more information on pruning tools, see http://www.caes.uga.edu/publications/pubDetail.cfm?pk_id=7656#Tools.

Second, you might find it helpful to know some basic science behind pruning.  The extremely abridged CliffsNotes version is this: pruning promotes growth, and most regrowth occurs within six to eight inches of the cut.  For more information on the science of pruning woody plants, including an explanation of terminal buds, lateral buds, nodes, apical dominance, auxin, responses to pruning, etc., please see http://www.caes.uga.edu/publications/pubDetail.cfm?pk_id=6098

There are two main types of pruning.  The first type is called “heading back” or “shearing.”  With heading back, you remove the ends of the twigs and branches.  This practice encourages thick growth near the site of the cut, and the most vigorous growth will be near the cut and toward the outside of the plant.  This may sound great, but as Walter Reeves says, if you head back to just one height (as you might with power hedge clippers), “you’ll end up with an eggshell of greenery covering an interior of brownery.”  That’s because you need light to reach the interior of your plant in order to have leaves grow there.  The solution?  If you want to head back your hollies or your boxwoods, try to head back to several different heights.  And make some thinning cuts (see below) so the light can get to the inside of your plant.  Caveat: this technique will result in a less formal look.  For information on pruning hedges, see the “Hedges” section of http://www.caes.uga.edu/publications/pubDetail.cfm?pk_id=7656#Guidelines

For most plants, the preferred method of pruning is called “thinning.”  With this method, you remove the entire branch or shoot all the way back to the main trunk, limb, or branch.  This approach encourages new growth within interior portions of a shrub.  The best way to prune a tree is to cut back to the main trunk, a lateral branch, or a bud.  Never ever leave a stub!

For more information and to see some pictures of proper pruning techniques, see http://www.caes.uga.edu/publications/pubDetail.cfm?pk_id=7656#Technique, http://www.caes.uga.edu/publications/pubDetail.cfm?pk_id=6098#Types, and
http://www.clemson.edu/extension/hgic/plants/landscape/trees/hgic1003.html.

Pruning Trees
Improper pruning is the second leading cause of tree death (construction damage is the first).  The most important rule of tree pruning: do not top trees.  In other words, never cut branches back to stubs like the crape murderers do.

Crape Murder in Midtown Columbus

Good job, Carmike! Thanks for not crape murdering!

Why not?  Topping produces a ton of new shoots just below each cut—the tree has to replace all the leaf area it just lost.  The shoots are not strong like the old branches, and they are prone to breaking.  Topping also destroys the natural branching structure of a tree, and it actually makes the tree more top-heavy and prone to wind damage.  And topping opens the tree to decay, infection and insect infestations.  For example, crape myrtles that are topped are far more susceptible to powdery mildew than crape myrtles that are properly pruned.  So what do you do if you think your tree is too tall for its space and you don’t want to take it down?  Thin the tree by removing branches back to their point of origin.  Cut branches back to a strong lateral branch, to the parent limb, or to the trunk itself.  If you’re in doubt about the best way to prune your tree to reduce its height, you may want to consult an arborist.

There are several other important rules of thumb for tree pruning.
* Never remove more than 25% of the foliage in one year.
* Do not paint the pruned area of a tree.  Just do a good cut.  And do it in the spring if possible, when wound closure is fastest.
* How do I make a good cut, you ask?  Well, you want the cut to be as close to the trunk as possible.  Most tree folks recommend the “three-cut” approach.  First, you want to make a notch on the bottom of the branch—the notch should be several inches from where the branch meets the trunk.  Second, cut through the limb from the top, a little farther from the trunk than the notch you just made.  Third, remove the remaining stub by cutting just outside the branch collar.  For a picture of the proper three-cut technique, see http://www.caes.uga.edu/publications/pubDetail.cfm?pk_id=6098#Types (Figure 8(b)).  For more information on tree pruning in general, see http://www.clemson.edu/extension/hgic/plants/landscape/trees/hgic1003.html.

Crape Myrtle
With this information in mind, I can now explain how not to commit crape murder.  First of all, for a large old crape myrtles in tree form, there’s just no reason to do much pruning.  Just remove dead wood and suckers, and you should be good to go.

There are, however, times when you may need to prune a crape myrtle.  If you need to prune, do it in late winter (late February is a great time).  If you’ve got a baby crape myrtle and you want to make sure you are encouraging a tree shape, select between three and five nicely spaced shoots as the main trunks and cut out the rest.  Remove the side branches from the bottom half of the shoots.  And remove suckers.  As the crape myrtle continues to grow, you will want to continue to remove the lower branches so that your canopy starts between three and four feet above ground level.

Now, if your crape myrtle is growing up into the roof of your porch, I’m sad to say that it’s just plain in the wrong place—it should have been planted farther from the house.  Bless your pour little heart.  You can try to thin the tree.  Another option: you can try growing your crape myrtle as a shrub.  According to the UGA extension, a crape myrtle will grow as a compact shrub if you prune the stems back to approximately six inches above ground level each year.  For an “intermediate size” crape myrtle shrub, prune by removing growth smaller than a pencil.  Don’t cut large limbs or leave stubs!  For more information on pruning crape myrtles, please see http://www.caes.uga.edu/publications/pubdetail.cfm?pk_id=6861#Pruning and http://thedailysouth.southernliving.com/2009/02/24/what-concerns-p/.

Other Trees
Most trees, including ornamental flowering trees, hardly ever need pruning.  Just prune dead or diseased wood, and prune suckers.  You may also need to prune rubbing or crossing branches (for flowering trees, do this after flowering).  For more information, see http://www.caes.uga.edu/publications/pubDetail.cfm?pk_id=7656#Guidelines (Sections on Deciduous Shade and Flowering Trees and Broadleaf Evergreen Trees).  For an article on general care of ornamental cherry, plum, apricot, and almond trees, see http://www.clemson.edu/extension/hgic/plants/landscape/trees/hgic1018.html.

Fruit trees are an exception to this general rule.  Pruning and training are especially important for young fruit trees.  For information on pruning fruit trees, see generally http://www.walterreeves.com/food-gardening/pruning-fruits-and-fruit-trees/

See also:
Apple
http://www.caes.uga.edu/publications/pubDetail.cfm?pk_id=6364#Pruning
http://www.clemson.edu/extension/hgic/plants/vegetables/tree_fruits_nuts/hgic1351.html
Fig
http://www.caes.uga.edu/publications/pubDetail.cfm?pk_id=6802#Train
Peach
http://www.caes.uga.edu/publications/pubDetail.cfm?pk_id=6365#Training
http://www.clemson.edu/extension/hgic/plants/vegetables/tree_fruits_nuts/hgic1355.html
Pear
http://www.caes.uga.edu/publications/pubDetail.cfm?pk_id=6366#Handling
http://www.clemson.edu/extension/hgic/plants/vegetables/tree_fruits_nuts/hgic1351.html

Pruning Shrubs
In this section, I’ve listed some of the most common shrubs grown in Zone 8 and given a short explanation on when and how much to prune each plant.  If possible, I’ve included a link to a fact sheet on the shrub.  For more plants/information, see http://thedailysouth.southernliving.com/2011/05/09/can-i-prune-it-now-grumpy-cuts-to-the-chase/.

Azaleas.  Prune in the spring after the plant flowers, and only if necessary.  Do not prune if the azalea looks good.  See http://www.caes.uga.edu/publications/pubDetail.cfm?pk_id=7732#Maintenance.

Beautyberry.  Prune in late winter/early spring to thin out the plant prior to spring growth.  Avoid fall or winter pruning.  You can cut back pretty hard because beautyberry flowers and fruits on new growth.  See http://www.clemson.edu/extension/hgic/plants/landscape/shrubs/hgic1086.html.

Blackberries.  Make sure you know what kind of plant you have.  Most blackberries have a biennial cycle, and they fruit on last year’s growth.  So after the plant fruits, you should only cut out the canes that fruited this year (they’ll probably look dead, anyway).  But do not cut out the new vegetative growth.  Now, if you have “primocane” blackberries, they fruit on first-year growth, so in winter you can cut off all the canes.  For more information, see www.caes.uga.edu/publications/displayPDF.cfm?pk_ID=6371;
http://www.walterreeves.com/gardening-q-and-a/blackberries-and-raspberries-fruit-growth/.

Blueberries.  If you’re growing rabbiteye blueberries (the kind that do best in Zone 8—they’re actually native to Georgia), you won’t need to prune much except when you plant the bushes.  When the bushes reach four to six feet in height, you’ll want to start a “cane renewal program” and prune between one and three of the largest canes back to 24 inches or less.  Prune in late winter.  See http://www.caes.uga.edu/publications/pubDetail.cfm?pk_id=6793.

Boxwood.  Prune in spring or summer.  Please don’t prune when it’s freezing.  Boxwood will not likely tolerate a severe prune, so don’t ever reduce by more than 25% at a time.  Remember to do some thinning cuts so that light and air can reach the interior of the plant.  See http://www.walterreeves.com/gardening-q-and-a/boxwood-pruning/.  Please note: Walter Reeves says that power hedge trimmers “are the devil’s tool when it comes to boxwoods.”  Also note: what you think is a boxwood may actually be a holly.  To tell for sure, pinch a small twig.  If the buds are directly opposite each other, then you’ve got a boxwood.  If the buds are not directly opposite but are, instead, “alternate,” you’ve got a holly.

Butterfly Bush.  Prune in late winter/early spring to thin out the plant prior to spring growth.  Avoid fall or winter pruning.  According to Clemson, “pruning butterfly bushes to within one foot of the ground annually enhances the flower display.”  See http://www.walterreeves.com/gardening-q-and-a/butterfly-bushes-pruning-2/

Camellia.  Important note: Camellias require very little pruning.  They also grow very slowly, so they don’t recover quickly from pruning.  I don’t understand why folks waste time shearing them into orbs.  They have a round growth habit anyway.  That said, you can cut back the wild shoots to maintain shape.  You can also control the growth of camellias using thinning cuts.  For sasanquas, which bloom in the fall, wait until late winter/early spring to prune.  For japonicas, which bloom in the winter, wait until after they bloom to prune.  You can cut out dead or weak stems any time.  http://www.clemson.edu/extension/hgic/plants/landscape/shrubs/hgic1062.html.

Elaeagnus.  Grumpy Gardener says that the best time to prune elaeagnus is “any time you have a chainsaw.”  I second that emotion.  I would also add that you may need a stump grinder in addition to your chainsaw.

Gardenia.  Prune in late winter/early spring to remove straggly branches.  You can also prune in the summer after the flowers turn brown and begin to drop.  Do not prune in late fall.  See http://www.walterreeves.com/landscaping/gardenia-when-to-prune/.

Holly.  Most evergreen hollies will tolerate a pretty severe prune, and they can be pruned most any time.  If you have a holly that produces berries that you like, prune in winter before spring flowering.  If you don’t care about the berries, you can prune just about any time during the growing season (late winter and early spring are always good times).  Remember—the holly will branch where you cut it.  Many of us use hollies in hedges.  For information on pruning hedges, see the “Hedges” section of http://www.caes.uga.edu/publications/pubDetail.cfm?pk_id=7656#Guidelines.

Hydrangea.  With hydrangeas, you need to know what kind you have.  Bigleaf, French, and Oakleaf hydrangeas bloom on old wood, which means that you should prune after flowering.  Peegee and smooth hydrangeas bloom on new wood and can be pruned back in late February or early March (if you prune back severely, you’ll get huge flowers but not a ton of them).  For information on hydrangea identification and pruning, see http://www.walterreeves.com/landscaping/hydrangea-identification-and-pruning/.  You may also want to read “Why Your Hydrangea Didn’t Bloom.”

Loropetalum.  Prune in March after the plant flowers.  If your loropetalum is very overgrown, you may want to replace it with a smaller cultivar if you don’t want to prune several times a year.  http://www.walterreeves.com/gardening-q-and-a/loropetalum-pruning/ and http://www.walterreeves.com/gardening-q-and-a/loropetalum-bush-pruning/

Muscadines.  Prune in February or early March.  See http://www.caes.uga.edu/publications/pubDetail.cfm?pk_id=6826.

Oleander.  Prune just prior to spring growth; oleander flowers on new growth.  In my experience, it’s best to wait until you’re pretty sure you will not have a frost.  So mid-March or so.  Always be careful with oleander.  It is one of the most toxic ornamental plants in the Southeast.

Pyracantha.  Grumpy Gardener says that pyracantha will eat your house if you don’t keep it pruned.  The best time to prune pyracantha is after flowering/fruit sets so you can make sure you’ll have berries in the fall (berries are only produced on old wood).  WEAR THICK GLOVES.  See http://www.walterreeves.com/gardening-q-and-a/pyracantha-pruning/.

Roses.  Prune hybrid teas, grandifloras, and floribundas in early spring when new growth begins.  Prune climbing and old garden roses roses after flowering.  See http://www.clemson.edu/extension/hgic/plants/landscape/flowers/hgic1173.html.

Knockout Roses.  Prune knockout roses in late February or early March.  See http://www.walterreeves.com/gardening-q-and-a/knockout-rose-how-low-to-prune/.

Whew!  I know you’re tired if you’ve stuck with me to the bitter end here—thank you, thank you.   Now I will have a glass of wine, listen to the rain, and peruse the new issue of Southern Living that arrived today.  Have fun with your pruning projects, and be safe!