On March 7th I wrote, “Patience is the key for winter-damaged landscapes.”
I went on to say, “The best plan, for now, is to pause and wait 2-3 weeks before making pruning and replacement decisions.”
Then I boldly said, “By the end of March we will know more (about what plants survived and what needs to be replaced)….”
It’s now 5 weeks later and although we know some of the plants that did not survive the winter freezes, there are still a few we are waiting on.
Climate factors that impact budding include day length, soil temperatures, amount of sunlight, and moisture.
At the end of February, most Deodar Cedars looked like this one.
In the last 10 days, the same tree has burst into life.
Recovery of winter-damaged plant material has been slower than expected for two reasons:
First, soil temperatures reached the critical point of 55 degrees on March 11th, a few days ahead of the average. They remained at or just above 55 for a week. Then, instead of continuing to warm up, they dropped below 55 degrees until the last day of March. The cooler soil temp slowed plant recovery. Over the last 10 days, soil temperatures have gradually increased to 60 degrees and finally, plants that appeared to be dead are starting to bud.
Now, the biggest factor impacting budding is the severe shortage of moisture. During what is supposed to be one of the wettest times of the year, Oklahoma City has not had a ¼” rainfall in 18 days. If you have not started regular odd/even watering, it is a good possibility that your plants are struggling to rebud due to lack of moisture.
(Sorry for all the geeky weather data. It is critical information for the landscape. Do you think I talk too much about weather statistics? Could this be the reason people often avoid me in social settings and sometimes walk away leaving me talking to myself? Please do not respond to this email with an answer to that question; it is a rhetorical question.)
Plants that took the brutal cold in stride:
Boxwood – Many varieties with varying growth patterns. They are vigorous evergreen shrubs with bright green foliage. Favorites: Green Velvet, Ground Mountain.
Juniper – With needle-like foliage in greens, blues, and golds, there is a variety for almost any location: groundcover, spreading shrub, or upright growth. Favorites: Saybrook Gold, Taylor, Blue Rug, Blue Arrow.
Junipers didn’t mind the record low temperatures this winter. Taylor Juniper has a narrow columnar form that creates an elegant look.
Endless Summer Hydrangea are flushing out lower on their branches.
Boxwood took on the extreme cold and won!
Yew – Dark green foliage with bright green new growth in the spring. Prefers to not be in the hot afternoon sun. Favorites: Dense Spreading, Capitata Japanese
Many Deciduous Shrubs – Oakleaf and Limelight Hydrangea, Goldmound and Bridal Wreath Spirea, Forsythia, Red Twig Dogwood, just to name a few.
Oakleaf Hydrangea are full of new growth.
Yews didn’t even notice the deep freeze of 2021.
Yew – Dark green foliage with bright green new growth in the spring. Prefers to not be in the hot afternoon sun. Favorites: Dense Spreading, Capitata Japanese
Many Deciduous Shrubs – Oakleaf and Limelight Hydrangea, Goldmound and Bridal Wreath Spirea, Forsythia, Red Twig Dogwood, just to name a few.
Commonly used plants that did not handle the extended, record cold well:
Indian Hawthorn – An evergreen, mounding shrub with small flowers in the early summer and berries in the winter. Popular as a foundation shrub and in mass plantings. Many are completely dead, and others are still alive near the base of the plant. Most will need to be removed but could be cut back to the live branches and allowed to regrow over a couple of seasons. I still believe it is a great plant for our area and would not hesitate replanting.
Indian Hawthorn are either completely dead or like this one have a few green leaves. If you decide to prune the dead out and keep the plant, expect it to take a couple of growing seasons to regain good shape.
The normally silvery green foliage of the Elaegnus is light brown this spring. Surprisingly we are see some with a green cambium layer that may produce new leaves after all.
Elaeagnus – Most common variety is Silverberry - a dense evergreen with a silver-green leaf. Best planted in areas where it can grow naturally with minimal shearing. Most are dead, but in the last few days we have noticed some with green cambium tissue higher up in the plant. Before pruning or removing, check for live branches.
Holly – There are many varieties of holly and each variety responded to the extreme cold differently. Burford Holly, Yaupon Holly, Nellie Stevens, and few others started producing new growth this week. Most will recover, but there will be some that will not. The good news is this time of year is a great time to do major pruning on hollies anyway.
The branches of many Holly varieties started producing new green buds this week. Overgrown Holly can withstand heavy pruning to reduce size when done early in the growing season. With all the freeze damage, now would be a good time to reshape your Hollies.
Now that Nandina have started putting on new growth you can go ahead and prune out the dead. Find the higher point on a branch where new growth has started (first photo). Prune just above the new growth (second photo) on an angle leaving a clean cut (third photo).
Nandina – This one surprised me. Nandina will drop their leaves during some colder winters, but I have never seen them suffer this much damage. An older favorite Nandina, Heavenly Bamboo, started leafing out this week. Many improved varieties, such as Gulf Stream, Firepower, etc., still need more time.
Live Oak – Southern Live Oak is a large evergreen tree that grows as far north as Hardiness Zone 7 but prefers to be in more southern climates. Some years winter temperatures will dip low enough to cause them to lose most or even all their leaves, but this year they went completely dormant. We started seeing some budding of new leaves this week. It is still too early to know if all Live Oaks will recover.
Pyracantha – A bold upright evergreen shrub with white spring flowers and bright red berry clusters late in the season that they keep through the winter. An excellent plant for espalier. Many are completely dead while others will come back from the base of the plant.
The best way to reduce the size of an overgrown Nandina is to remove the tallest branches at ground level. Nandina is a plant that does not look best when shearing is used to reduce size.
One of the greatest disappointments from this winter is the loss of three years spent espaliering this pyracantha along a walkway.
This photo is from last fall.
This photo is from this spring.
Pyracantha didn’t do well this winter. If you have some green at the base and can be patient to let it grow (first photo), start pruning at the top a few inches at a time (second photo) until you see a green cambium layer just below the bark (third photo).
Crape Myrtle – Our longest summer-blooming small tree and/or shrub. A deciduous plant that is one of the last to produce new buds each spring and it is common for them to have some die back each winter. Most need a few more weeks before we will know how much they are damaged. This week some started growing at the base, a few started budding up the trunk at 12-24”. We are still finding many with green cambium when you scratch the bark, but others have brown cambium and brittle branches. A common trend we are seeing is ones that do not have green cambium were not in good health last year suffering from scale, aphids, powdery mildew, or were newly planted last year.
Before you prune Crape Myrtles scratch the bark high up on the plant in a few places to see if there is any green just below the bark. If there is wait a little longer to see how high it is going to bud. If it is brown when you scratch the bark, it is ok to start pruning.
Always make cuts on the angle when pruning.
Try to select places to make pruning cuts just above new buds that are on the outside of branches.
The goal is to have branches at a similar height when finished.
I was paying my way through college by doing lawn work during the record cold in 1983.
In the spring of 1984, I removed a lot of old, mature pyracantha and crape myrtles that did not survive.
Steps for pruning and/or deciding to remove winter-damaged plants:
1. Inspect the plant for new growth. If you do not see any new growth, you may want to give it another 10-14 days before making pruning or replacement decisions.
2. When you prune, start at the tips of the branch, and gradually move down until you see a green cadmium layer. The cambium is the tissue right below the bark layer.
3. Once you reach live cambium, prune the plant to the best shape possible considering the conditions. If you are pruning back to a live bud, prune just above the bud on an angle.
4. If you must remove more than 50% of an evergreen, take into consideration the amount of time it will take the plant to regrow back to a desired size. It may be best to remove and replace. If the plant was overgrown, then the reduction in size due to the freeze may be good.
5. If Crape Myrtles are dead all the way to the ground, they can be cut down and allowed to regrow. This season the plant will produce several shoots that will result in a shrub-type plant. Next spring remove all but 5-7 of the best branches. Over a couple of seasons, you will be able to regain the multi-truck tree shape you desire.
6. Fertilize your plants to promote new growth and replenish nutrients the plant is using to recover from the winter damage.
If your landscape is like mine, it looks vastly different this spring than it did last year. My favorite tree is missing its oval shape this spring because of last fall’s ice storm. My three years of work creating an espalier Pyracantha is lost. The fiery red of my nandina has been replaced by dull browns.
But, all is not lost. It’s spring. Flowers, shrubs, and trees are blooming. Fescue and rye lawns are dynamic and Bermuda lawns are turning greener every day. There are more things sprouting new life than are not. I’m excited for the opportunity to try something new in a few places where things didn’t make it in my landscape.
If you have questions about your plant material, give us a call.
Lorne Hall
Hall | Stewart Lawn + Landscape
(405)367-3873