Winter Tree Manual
How to Winterize Your Trees and Plants
If you’re anything like us, winter is a great time to hunker down with family and cozy up to the fire with a good book. It’s also a fabulous time to inspect, prune and protect your trees. Put down that John Grisham for a moment and read through our winter manual on how to care for your trees this winter!
Our Winter Tree and Pest Manual will cover:
Winter Inspection & Pruning
During winter, when deciduous trees shed their leaves, it’s the best time to see the architecture and branch structure of a tree. This makes winter the perfect time for tree inspection and structural pruning. And there’s less pressure in the winter from tree pests and pathogens which allows us to do our jobs more effectively. In winter, these so called “naked trees” (wait, I thought this was a family-friendly tree company!) present an excellent opportunity for us to inspect for anatomical and architectural defects, tree decay and malformed unions—and work with you to prevent problems. With that said, at Carolina Tree Care, we try not to prune too early. We don’t want to expose any roots especially when a tree is dormant and cannot heal until it begins growing again.
What is a malformed union?
We’re in the tree business so we’re not talking about Kate Beckinsale and Pete Davidson. A malformed union is when two stems or trunks grow from a single union. If they are the same diameter, they’re considered codominant and often have what’s called “included bark” (a.k.a. bark in the center of the tree). Why do you care? Because trees with malformed unions are more susceptible to breaking especially those with included bark. We’re here to help.
Winter Tree Protection
Horticultural oils are good preventative measure in winter. Oils work by suffocating insects and larvae. The sprayed oil clogs their spiracles (i.e., breathing pores) which research indicates may inhibit feeding. In addition, the oil dries out their exoskeletons. Importantly, since oils only affect the development process of certain insects, they do not kill everything else non-selectively. They are environmentally friendly and less harmful to predators than other techniques – a nice, gentle treatment to get ahead of issues.
How much oil is needed?
In general, we opt for full coverage where we spray the whole tree and bark. Because oils only last a day or two until they evaporate due to sun and/or wind conditions, it may be necessary to spray a few times. We typically advise our customers to apply multiple layers (i.e., systemic vs. one-time treatment) especially for aggressive pests and scales. At a minimum, we’ll need to spray at least once. The more we spray, honestly, there are diminishing returns. If you get above three or four oils between winter and spring, it’s overkill. Don’t let anyone tell you otherwise.
Do you use a lot of oil on trees and plants?
Dormant oils range in concentration from 1% to 5%. When trees have no foliage, we can use a heavier concentration; however, as plants start budding in the spring and insects are more active, we lower the concentration. Trees and plants can become toxic (what’s known as cytotoxicity) when a new tender, without a waxy cuticle, is exposed to heavier oils. A good rule of thumb is a 3% concentration in January and February.
How do you know when to spray?
In general, for winter tree oils, we encourage you to schedule a spray crew for late January/early February. Temperature is a factor in when to spray. If temperatures are still fluctuating, where it’s warm and sunny and then dropping below freezing, we won’t spray. We are extremely mindful of the transitions between seasons—and associated logistic limitations—and can guide our services and timing appropriately to best serve you. On your behalf, we pay close attention to the area climates, microclimates and phenological indicators. Because every year is different (e.g., warm spring or delayed spring), we will watch your trees – especially dogwoods and cherries which are prone to fungal issues – to see when they begin developing and their buds start to swell as winter transitions to spring. We’ll even pay attention to your specific yard: do you get a lot of sun on one side and more shade on the other? We can plan for that. We also track growing degree days, so we know when to initiate spraying. As any expert will tell you, the timing is critical. When shoots and foliage are tender, and do not have waxy protection, spores can land on an undeveloped juvenile. We call this the “window of vulnerability.” At this time, we want to spray a protective, preventative, fungicide cover. Lastly, when it comes to needle blight, we pay attention to the length of your needles and spray based on elongation. If we’re expecting a two-inch needle, we will spray when the needles are an inch long (i.e., half elongated) and re-spray in two-week intervals.
How will we know if it’s working?
Unless you have a highly visible, recurring issue, horticultural oils are like taking probiotics. You have to trust that they’re working behind the scenes to control pests that lay eggs and overwinter on your trees (e.g., caterpillars, hemlock woolly adelgids). You’ll have a better idea of the effectiveness when spring arrives, and the pests have been minimized.
What advice would you give us?
Pay attention to the signs and call us to schedule in advance! Oftentimes, we receive pest-related calls in early spring but sometimes it’s too late. While we can do later sprays, there is no scientific evidence to support the efficacy at this time.
Our Winter Spray Programs
At Carolina Tree Care, we have two spray programs: one for leaf spot on deciduous trees and another for needle blight on evergreens. With our standard program, your trees and plants receive three sprays, two weeks apart. Depending on your concerns, we have organic or synthetic treatment options. Our synthetic options are a little stronger and more effective yet still relatively safe. For those concerned about drift onto other plants, we have organic treatments that are less harmful to the environment; however, these are typically a little more expensive and less effective. Our winter spray programs will get your trees or shrubs in a good place for spring. And, if desired, we can follow-up in early spring with an environmentally friendly insect growth regulator. Whatever works best for you and your property. Please note: We also have an autumn spray program for evergreens that have a high spore load in the fall. See our Fall Manual for more information on the benefits of fall spraying.
Winter Tree Cabling
Guess what, winter is a great time for cabling, too. Like pruning, we can better see the structure of the tree during winter and determine the necessary cabling physics to provide the optimal mechanical advantage. Do you have an oak tree like the picture-perfect Angel Oak tree? Or a beautiful willow leaning over a lake? We can help prop up your trees and branches for aesthetic or preventative purposes. Beyond cabling, we leverage the right ANSI supplemental support system to meet your trees’ specific needs (e.g., cabling, bracing, guying, staking). In general, the best time to cable your tree is after the leaves fall and before any ice comes. With heavy wind and ice, the chance of branch failure is higher when foliage is still on the branches. In other words, if your branches are weak, they’re more susceptible to breaking when heavily laden with ice and/or facing strong winds.
North Carolina Trees to Care for in the Winter
In North Carolina, there are a number of trees to care for in the winter (e.g., dogwood, cryptomeria, willow, and anything in the Rosaceae or rose family including fruit trees like apples, cherries, peaches). But other trees like Leyland cypress that are not known to be highly susceptible to fungus may require winter care if they are planted incorrectly—for example, only six feet apart allowing their roots to rot. A typically healthy tree planted in the wrong location where it doesn’t get enough sun or wind and stays consistently wet may be a good candidate for some extra winter care. Unsure about your trees? We’re happy to provide a free estimate. Here’s a clue for you: did one of your trees lose its leaves early last year? If the answer is yes, we’re here to help.
Prepare Now for the Blooming Season!
The winter is a great time to prepare your trees and shrubs before the blooming season arrives, but DIY projects can be time-consuming.
Let us take that off your to-do list. Fill out this form to get in touch with your area’s Arborist representative to schedule a an estimate or consultation today!