06/15/2023
Urban Ag Council of Georgia Article - Georgia's professional association for the landscape, turfgrass and horticulture industry.
To Prune or not to Prune as We Assess Last Winter’s Damage
By Dr. Bodie Pennisi, Rick Smith, The Pruning Guru, and Dr. Jean Williams-Woodward
Without a doubt this last winter, Mother Nature threw some cold weather our way.
Having a hard freeze in December 2022 and January 2023 had homeowners and landscapers testing
their patience. Not only were they concerned if their shrubs survived, but they wondered if there’s
something that could be done to help things along. The question was, do we prune the damaged
plants now or wait? As difficult as it was, we kept telling folks to wait and see how the damaged plants
were going to respond to the spring warmup. Now that the dust has settled, we take stock.
We gathered information from North Georgia, Athens, Atlanta, Griffin, Fayetteville, and Stockbridge,
and visually assessed plant damage and recovery.
Naturally, the more northern locations experienced more severe symptoms but damage was
observed all throughout the state. Many shrubs, even some trees, and evergreen groundcovers were
affected. As ever - and to keep us from making blankets statements - boxwoods presented an
inconsistent picture - plants south of Atlanta, Athens, and White County showed damage (severe in
last two), while in north Metro locales they showed far less problems. Overall, the plants that took the
brunt were Osmanthus (Tea Olives), Pittosporums, Gardenias, Loropetalums, and Camellia
Sasanquas.
Osmanthus (Tea Olives) had the most noticeable effect with rapid defoliation within 3 days after the
initial freeze. The second cold snap came after the new leaves started to come out, which was the
equivalent of a one-two punch. This was a very concerning as it is not a common event. The good
news is that most of the shrubs we have seen survived. They will appear weaker than normal this
year but should fully recover in 2025. Of course, that depends on dry spells, and any other adverse
conditions, which may slow growth.
Pittosporums also took a beating, especially if they were the (MOJO). The bark on these literally
exploded and caused their demise. Of all the species, this one was probably the most expensive to
replace for homeowners.
Gardenias were the plant that everyone asked the most about. Out of all the plants, these beauties
really tested our patience the most. In North Georgia, they stubbornly held off giving any indication
which way they’d go, and only recently showing signs of recovery. Unfortunately, some plants in most
northern locations did not survive (Rick has to replace his). Good news is that they too, are starting to
push out new growth.
Loropetalums and Sasanquas were probably evenly matched when it came to the amount of cold
damage they experienced.
Overall, north Georgia had 20+ different species of plants that were mildly to severely damaged.
Here’s the list:
1. Osmanthus
2. Pittosporum
3. Gardenia
4. Loropetalum
5. Sasanqua camellia
6. Boxwood
7. Rosemary
8. Hydrangea
9. Abelia
10.Indian hawthorn
11.Fatsia
12.Cleyera
13.Nandina
14.Mahonia
15.Azalea
16.Ligustrum
17.Distylium
18.Sweetbox
19.Hinoki cypress
20.Arizona cypress
21.Spring Bouquet viburnum
22.Daphne
23.Ajuga
24.Confederate jasmine
25.Creeping raspberry
26.Spirea
27.Liriope
28.Aspidistra
As far as symptoms are concerned – immediate one within the first few days is light-colored,
bleached foliage/shoot, later turning brown/dark brown. Afterwards and depending on further cold
exposure, we see individual branch death, top dieback, complete dieback, exploded/sloughing bark or
vertical cracking on trunks, slow leafing out, and/or reduced bloom presentation (see photo gallery).
Most often, freeze damage is seen on the west-to southwest-facing sides of plants. The damage is
directional, along the coldest gradient. The amount of damage has to do with what stage of growth
was present at the time of the freeze event. Those that were growing well and flushing new growth
were most damaged. Those not showing as much damage now are actually more stressed and
slower growing plants. Their growth developed after the freeze event.
Plants under trees, near buildings, and/or on higher ground fared better. The cold air sat in one spot
longer than other, or the wind blew in the same direction pushing the cold air against the plants.
Worst case scenario is when a freeze event is followed by a prolonged warm spell, and tailed by a
second freeze/cold exposure. During the middle part, the plant starts pushing new growth, which is
far more susceptible to cold damage. The new growth taps into stored reserves, and when killed by
the second cold snap, those spent reserves are gone for good. This depletion of stored reserves
weakens the plant, causing slow leaf out and recovery. If this freeze-warm-freeze happens again
during the winter/spring, it could be disastrous for the plant.
Back to the original question, do we prune or not prune? In our professional opinion, it is now time to
prune them. If they have not produced new growth presently, they probably will not. If they are
opening new buds, pruning them will help promote the energy from the root system to go where it is
needed.
