Is Your Native Shrub Too Tall? How to Resize!
- Nuts for Natives
- 2 minutes ago
- 5 min read
A number of native shrubs can be 'rejuvenated.'
Once you get your native shrubs in the right place, they will start to thrive and a lot of them can get quite large. In the some locations this is ideal. In others, they might become too large. This is where pruning comes in!
Pruning Basics
There are a couple of basics for pruning:
remove dead or diseased wood
remove crossing or rubbing branches (branches rubbing together can create wounds where disease can enter)
a general rule of thumb is not to remove more than 1/3 of a plant's size at any given time
You may also want to prune to remove suckers (weaker growth that stems form the base of a shrub or tree), to remove water sprouts (straight weak growth from branches) or to create better structure. There is another type of pruning called rejuvenation pruning and it can be used to resize shrubs that have become too large.
About Rejuvenation Pruning and Resizing Native Shrubs
I was reminded of rejuvenation pruning at an information packed talk this past August by Bill Cullina, Executive Director of the Morris Arboretum, past CEO of the Coastal Maine Botanical Garden, author, lecturer and noted authority on North American native plants. And these are just a few of his credentials! His talk was arranged by the Chesapeake's homegrown native preserve, Adkins Arboretum, as part of their Naturally Better landscaping series.
Bill Cullina shared really practical information we can all use. The number of shrubs native to the Chesapeake is significant. And a number of those also add three or four seasons of interest (flowers, berries, fall color and for some, interesting winter bark), always a big plus. Shrubs also bridge the space between shorter perennials and trees, adding the all important range of heights necessary to best support wildlife and to be more aesthetically pleasing in a garden setting.
There are cultivars resulting in smaller stature native shrubs -- summersweet 'Hummingbird' (Clethra alnifolia 'Hummingbird') and smooth witherod 'Winterthur' (Viburnum nudum 'winterthur') for example. Many of the straight species shrubs, though, can grow quite large once they mature. In urban gardens like mine, you may want to resize these shrubs from time to time to keep the right proportions. In larger gardens, you may need to rein in a thriving shrub in certain locations.
By way of example, look at these non-native yew shrubs (Taxus baccata) in my garden. I keep them because they provide a very effective screen from the street and a busy entrance to a City park. You can see they have grown too tall and are beginning to look awkward - a rejuvenation prune will allow them to regrow the following year and regain a more pleasing shape and somewhat smaller size. The marks indicate where one could rejuvenate prune to resize the shrub.
How to Rejuvenate Prune
Here are four best practices from Bill Cullina's talk.
The very best time to do this is in winter when the shrubs are fully dormant
Typically, when a plant is cut or pruned, the plant senses the cut as an injury and will try to regrow from the injured area. If you were to prune now, it's still warm enough that plants could try to push new growth out in response to the cut. That new growth is more tender and has not had time to harden off. This makes the growth very susceptible to damage. Instead, prune when the plant is dormant. The plant's energy will be in the roots and have the necessary energy stored to push the new growth in spring.
if you rejuvenate prune a shrub that blooms on old wood (last year's growth), rejuvenation pruning will mean you will have no flowers that year.
These oak leaf hydrangeas are getting to the point where they may be too large in scale for their location. If I rejuvenate prune to resize the shrubs this winter, I will not get any summer blooms in 2026. I will still get the foliage and fall colors though and the blooms will return the following year.
Native shrubs that bloom on old wood include:
Arrowood viburnum (Viburnum dentatum)
Black chokeberry (Aronia melanocarpa)
Carolina allspice (Calycanthus floridus)
Fothergilla (Fothergilla major)
Ninebark (Physocarpus opulifolius)
Oakleaf Hydrangea (Hydrangea quercifolia)
Possumhaw viburnum (Viburnum nudum)
Pussy willow (Salix discolor)
Red Chokeberry (Aronia arbutifolia)
Serviceberry (Amelanchier canadensis)
Sumac (Rhus typhina)
Winterberry (Ilex verticillata)
Witch hazel (Hamamelis virginiana)
Native shrubs that bloom on new wood include:
Beach Plum (Prunus maritima)
Beautyberry (Callicarpa americana)
Buttonbush (Cephalanthus occidentalis)
Coralberry (Symphoricarpos orbiculatus)
Elderberry (Sambucus canadensis)
New Jersey Tea (Ceanothus americanus)
Red twig dogwood (Cornus sericea)
Strawberry bush (Euonymous americanus)
Summersweet (Clethra alnifolia)
Wild Hydrangea including the cultivar Hydrangea "Annabelle' (Hydrangea arborescens)
If a plant bloom on new wood, if you rejuvenate prune you will not be forfeiting the next's years flowers.
Only rejuvenate prune an established shrub
This will typically be shrubs that have been growing well for at least 3 years as a rule of thumb. You also wouldn't want to rejuvenate prune a shrub that has recently been transplanted. You want them to be well established in their location before doing this type of pruning.
These are two native witch hazels in my garden. I would like them both to have the vase shape of the one on the left but since I transplanted both this year, I will wait another two years to rejuvenate prune the witch hazel on the right.
Cut back to about 10" to 18" above the ground to rejuvenate prune
This may seem quite drastic if you have not seen this type of pruning before. It really does work though.
This possumhaw viburnum (Viburnum nudum) in my garden is about ten years old. It grew from a 2 to 3 foot high shrub to a beautiful vase shaped shrub about 6 feet high and wide. The dry conditions over the past two summers though resulted in a couple of dead branches here and there and now it is quite lopsided in shape with one 7' tall long arm on the right and short stubby branches on the left. I plan to rejuvenate prune this winter. I've outlined the branches as they are today (left), the cuts I plan to make (in black - center) and the type of growth I would expect to see next year (in green - right).
Bill Cullina notes several other benefits to rejuvenation pruning. You may get more flowers and the fresher green growth is particularly attractive to the insects that require the plant to reproduce. You can watch all of Bill Cullina's talk here. It is packed with tips and info. There is plenty of time to watch between now and February when it's safe to rejuvenate prune!
Happy Gardening.
