When and What to Prune
If you haven’t read our last blog post, the aptly named Reasons to Prune , we suggest doing so before reading this one. A large part of good pruning includes understanding the reason you are pruning. Coming back to the reason throughout the pruning process will help you keep on track. When you lose sight of why you are pruning, you can also easily lose sign of how to prune and what your next cut should be.
What to Prune
This post is all about what to prune and when, which are the next pruning steps to keeping your garden healthy and thriving. Many plants don’t have to be pruned and only need occasional trimming to keep their natural form. Unless you are creating or maintaining a special feature like a topiary, we suggest working with the plants natural shape. It will greatly cut down on the amount of work needed.
Types of ‘Pruning’
As discussed in the Reasons to Prune post, there are different kinds of ‘pruning”, and shearing is one. One example of this process of cutting off the top of a plant Ornamental grasses and ground covers like liriope respond well to being sheared; old growth is removed before new shoots emerge from the ground. Another example of shearing is cutting off the ends of all the branches, which is often done to shape a hedge. This also works well. Some people like defined shapes and space between each plant, and shear back rows of foundation planting into a loosely round-ish or square-ish shape. Depending on what kind of plant you have, this may not be necessary and often times, it leads to plant decline due to lack of interior foliage. This process is often done with hand or power shearers versus pruners or loppers.
Trimming, Cutting Back and Cleaning Up
Trimming back a plant usually describes the light trimming a plant might need when it grows a random long shoot that is out of place. Also in this category of pruning is the clean up of perennials. Shrub roses such as Knock-Out and Drift Roses also fall in this category, since they are usually getting cut back to the same height, although some selective removal of old canes may occur as well. This is a more selective process than shearing.
This is the process of selectively removing branches from a tree or shrub, in a slow, thought-out process, keeping the plants’ natural shape in mind and thinning out to allow more light and air into the plant canopy. This isn’t the easiest or fastest method but depending on the plant, it may be the best method.
When to Prune
There are two ways of looking at this; if you want to think of it as a calendar of chores, here is a link to our Arkansas Gardening Calendar. You can look at each month for what should or should not be pruned at that time.
You can also think of pruning in categories and generalities; evergreen shrubs versus spring blooming shrubs. We thought that the most helpful way to look at it might be by plant categories with a little more in depth information on each. We start with some easy straightforward ones and build up to more complicated categories, like the ever tricky hydrangea! By the way, if that’s what you are most interested in, here is a post all about hydrangeas, include when to prune different species.
If you have a specific pruning question that isn’t addressed here, please call or email us before making the first cut. We don’t want you to cut a spring bloomer right before bloom time and miss out on all your blooms, for example!
A clean up of groundcovers like liriope, sometimes commonly called monkey grass, should be done before new growth begins in the spring. February is a great time to do this. Shearing back to remove winter damaged leaves before new green shoots emerge makes the clean up process easier and the plant will most likely flush much stronger than it would have if it was also struggling to keep damaged leaves growing.
Shearing isn’t recommended for all groundcovers; for example, vinca minor and semi-evergreen perennial groundcovers don’t really need pruning but might benefit from a light trimming. Or, if they have grown out of bounds, a heavier cut back and root prune (a whole other topic!).
Other groundcovers like Asiatic jasmine are sometimes sheared into short hedges, all the same height. This can be done in February as well, before new growth begins. This will help the area look more consistent as it grows.
Perennials and Hardy Ferns
Hardy ferns and most perennials (there are exceptions such as hellebores which are late winter blooming) can be cleaned up in the fall as needed. Unless you are keeping seeds for spring seeding or wildlife, spent blooms and stalks can be removed. Dead or diseased branches can be removed then as well. For non-woody, or herbaceous, perennials like hostas whose leaves die back in the first killing frost, you can remove the leaves.
A heavier handed cutting back of perennials should be done in February so the new growth comes back strong in the spring. Keeping the extra growth on between fall and late winter will help protect the plant from winter damage.
Since new growth for The Autumn fern, a popular evergreen fern, should be cut back now before new growth begins. Also, clean up any evergreen perennials before their new growth shoots up. Phlox
Hydrangeas (Timing depends on species)
As mentioned above, hydrangeas are interesting because different species needs to be trimmed differently for best results. Here is a link to the hydrangea post and quick details for different species are below. Remember, if you aren’t sure which kind you have, come talk to us before pruning.
Mophead and Lacecap Hydrangeas (H. macrophylla)- After bloom in June/July
Oakleaf Hydrangeas (H. quercifolia)- After bloom
Panicle Hydrangeas (H. paniculate, includes the popular Limelight)- fall, winter, early spring
There is always a bit of confusion about when to prune everblooming shrubs like Endless Summer Hydrangeas; since they bloom all summer, you can deadhead spent blooms throughout the season, then prune in the fall.
Spring Bloomers (After Blooming)
Most spring bloomers, especially ones that bloom in the early spring, such as quince and forsythia, can be pruned after blooming ends. Trimming in the fall or winter will remove flower buds. Light shaping can be done at the end of the growing season as needed but keep in mind, reducing plant volume will reduce blooms.
Prune back spring blooming viburnums and loropetalums after blooming as well.
Spring blooming spireas, such as Bridal Wreath, can be thinned after blooming. Avoid shearing back, as this will alter the graceful natural shape of the plant, in a way that’s hard to recover from.
Azalea (After spring blooming)
Azaleas have a wonderful natural form so it’s best to work with that when pruning. Look for the tallest branches that need trimming back and follow the branch down under the canopy height you are trying to keep. Prune just above a fork in the branch to encourage further branching. As a good rule of thumb, do not remove more than 30% of the plant at any one time. Since azaleas should be pruned mostly for shaping reasons, this shouldn’t be an issue.
Encore azaleas bloom often… so when do these get pruned? Same time as ‘regular’ azaleas, after the spring bloom!
Roses (Timing depends on rose type)
Prune your Knock-Out, Drift and Hybrid Tea roses around Valentine’s Day each year, but wait until after blooming to prune your climbing roses. Also wait to prune any other roses that only bloom in the spring until after they bloom.
Pruning shrub roses is pretty simple but important because they only bloom on new growth. This is why pruning out old, unproductive canes is important, as well as removing obvious dead wood. The goal with pruning shrub roses is to encourage new growth; you can cut Drift Roses back to about 8” off the ground, in a rounded shape. With Knock-Outs, you can prune those down to about 18” off the ground, and taking note of the remaining structure left. Remove shoots that cross through other branches, or ones
Hybrid Tea roses usually have many less canes than shrub roses. Identify the healthiest looking 5 to 7 canes and keep these, pruning to a height of around 18 inches off the ground. Remove old, unproductive canes. The easiest way to do to this is to cut the whole rose back to around 2 feet then make selective cuts and cane removals as previously described.
Ornamental Grasses (February)
The last few categories have been a little more complicated but here is an easy one! Let grasses to their lovely winter thing until February, then gather the top growth into a bundle and tie with twine about 2 feet off the ground. Most grasses can be sheared down to a height of about 8 to 12 inches off the ground. Taller grasses can be sheared on the higher end of the this and dwarf grasses on the lower end. The method of tying up the bunch makes clean up much easier!
This is a big one and it’s often done incorrectly. Avoid crape murder… read this post for details. Spoiler alert, less is more with crepe myrtles!
Camellias (After blooming)
Pruning of camellias is can be done for a variety of reasons and the reason will determine the pruning type. You might prune to remove dead or dying branches; this will help new growth emerge. If there is a severe scale issue, pruning the plant back hard (as well as treating the pest) could help it recover more quickly and vigorously. Pruning of camellias can also be done to re-shape, although we suggest working with the natural shape, as opposed to severe pruning or shearing. And last but not least, if you are growing yours as an espaliered tree, that will take some trimming, pruning and shaping.
As far as timing goes, any hard pruning should be done after bloom period ends, which differs between species. Lighter trimming can be done other seasons as needed but keep bloom time in mind (C. sasanqua bloom in fall/early winter, C. japonica bloom in late winter/early spring) so as to avoid removing too much before blooming.
Deciduous Trees (February)
Prune in late winter or early spring before new growth emerges. Trimming trees should always be a thoughtful process; consider each cut before making it. Pruning to shape trees is best done when they are young. As the trees mature, removal of branches growing into the canopy of the tree or ones crossing other branches may be needed. ‘Limbing up’ is the process of raising the canopy height of a tree and is the gradual removal of lower branches and twigs as the tree grows.
Broadleaf Evergreens (Early spring)
Prune boxwoods, hollies and other broadleaf evergreen shrubs in the spring after they flush out for the season. You can also lightly, selectively trim during the summer.
The above recommendation is for shrubby branched evergreens; ones with shoots that come out of the ground, instead of branching off a trunk are different. Plants with this cane-like growth pattern includes fatsia, nandina, mohonia and others. For these plant types, remove tall canes as needed to a 2-4 inches above the soil line. This thinning process won’t have to be done each year, only occasionally… and sparingly. It should only be done when these taller canes are too tall and shading out the majority of the plant canopy.
Most needleleaf evergreens don’t require trimming and can even start looking wonky with pruning so have a plan before trimming. Evergreens grown as spirals, like Blue Point Juniper often is, will require shearing back into shape a few times a year.
Summer Blooming Shrubs (Timing depends on plant)
This is a large group of shrubs and contains many different kinds of plants. Let’s talk through a few of the most popular, starting with summer blooming spireas such as Goldmound. Shear this plant back pretty hard in February; it blooms on new wood so the goal is to encourage strong new growth.
Indian hawthorns usually don’t require much trimming but if needed, they can be trimmed after summer blooming ends.
Gardenias can also be trimmed back after summer blooming ends. Bloom set for traditional gardenias is in the fall so avoid pruning during fall, winter or spring. This will remove flower buds. For re-blooming varieties, such as Southern Living’s Jubilation gardenia, you can prune after fall bloom.
Another summer bloomer is Rose of Sharon; this large shrub or small tree blooms on new wood and can be pruned during late winter or early spring before new growth emerges.
Annuals only grow for one season, either the warm or cool season here in Arkansas. Trimming usually consists of cutting back leggy growth to encourage new blooms. To keep annuals as healthy as possible, remember to fertilize throughout the season!
We have several new blog post for fruits; here are links to each. Pruning information for blackberries is in the post; fruit trees should be pruned in February, and blueberries should be pruned in the summer.
Pruning fruits is an intricate process, and is a whole post by itself… on each fruit type! We haven’t done these yet, so here are links to great resources from the University of Arkansas Division of Agriculture Cooperative Extension Service.
Research Before Planting
If you are thinking of adding to your landscape any time soon, and will be plant shopping, take note of the mature size of each plant before purchasing. Keeping a plant at half the mature size can be challenging to you, and potentially harmful to your plant. Choose a plant whose mature size will work in your space. We suggest measuring the space before leaving your home. If there are windows or a porch located behind the planting area, measure how far off the ground they are.
Last but not least, if you want a more mature looking landscape now, buy an older, larger plant as opposed to more plants that will then require more pruning maintenance. And exception to this would be when growing a hedge that will require frequent shearing anyway or green screen for privacy, where the goal is for plants to grow in together.
Still have questions? We can help; just come by and see us!