What happened to my Dogwood tree?
Published 12:32 pm Friday, March 10, 2023
Their graceful lying branches with creamy white flowers mark the beginning of Spring so beautifully. As I see them getting ready to bloom, I am reminded I have multiple calls a season regarding Dogwoods. Many of which question, “What happened to my Dogwood?” As usual, there is no short answer. By the way, those creamy white flowers aren’t actually flowers, they are modified leaves called bracts. Just in case you make it on Jeopardy, I thought you should know.
Dogwoods are a wonderful tree in their native environment. They complement the understory of a forest and don’t suffer from many of the stresses we subject them to in a home landscape. Growing in a lawn is not their native environment, it is a harsh reality to which they must adapt to survive. Does this mean we shouldn’t grow them – absolutely not! We always need to think, Right Plant, Right Place!
A dogwood adapts well to growing in a slightly acidic, moist, well-drained soil. As an understory forest tree, it enjoys protection from heat, cold, and the harsh wind that the larger, overstory trees provide. When we take a plant like this and throw it out in the full sun, subject it to the wind, heat, and cold, it causes stress. A dogwood is not a long-lived tree, averaging around 80 years in ideal conditions.
There are only a handful of disease and insect pests that plague dogwoods. The worst of which is dogwood anthracnose (Discula destructiva). The good news is this disease doesn’t usually happen in the coastal plains of North Carolina. Root rots often kill dogwoods in the coastal plains. These are phytophthora and armillaria root rots that can typically be traced back to soils staying saturated or inundated for long periods of time. The only insect that will do considerable damage to dogwoods is the dogwood borer (Synanthedon scitula). These holes can often be found near the base. The borer is the larva of a clear winged moth that resembles a small wasp. The borers will cause decline in older trees and death in younger trees. Look for sawdust at the base to see if you may have borers. More often, it is cultural issues, things that we can prevent, that cause dogwoods to die.
There are many cultural problems that a tree will be subjected to growing in a lawn which further compound these stresses. First is improper planting. This is true for most any tree I am called out to take a look at. Homeowners, and many landscapers don’t plant trees correctly. When planting a tree, first prepare the site. This includes getting a soil sample and taking a long look at how the site drains. Next, look for the first root on the tree, this should be planted no more than an inch below the soil surface. Dig a hole that is twice as deep and two and half times as wide as the root ball on your new tree. Backfill with the excavated soil until the tree will sit at the proper height (again, the first root should be no deeper than 1” below the soil surface). Now, plant your tree, lightly packing the soil around the roots. The soil should be lightly mounded to ensure water won’t pool over the top of the roots during a rain. Rain and irrigation serve to settle the soil over time. If you are planting a tree that comes in a container, it is important to check for and prune any circling roots. Nursery grown trees can be in pots for a long time. This can cause the roots to hit the side of the container and then to grow in a circle. If these roots aren’t pruned before planting, they will continue to grow in this circular pattern until they eventually girdle the tree. This cuts off the supply of water and nutrients coming from the roots and kills the tree.
Mulch is always a good thing, especially with dogwoods. A good ring of mulch, two to five feet in diameter and two to three inches deep, will serve many functions. It is like a blanket for the roots in the winter and an air conditioner in the summer. Mulch serves to moderate soil temperature effectively minimizing the highs and lows of the seasons. It will conserve moisture in the soil by lessening evaporation. A good layer of mulch will keep annual weed pressure down and lessen competition for nutrients with turf. Lastly, mulch protects the tree from mechanical injury by keeping weed trimmers and mowers away from the trunk. However, like most things in horticulture or life, it must be done correctly. Piling mulch upon the base of your tree, referred to as volcano mulch, has the opposite effect, often causing more stress than not having mulch at all. This will slowly suffocate the tree! When putting out mulch, be sure to keep it a good two to three inches away from the trunk.
Plant your dogwood in moist well-drained soil having full shade to partial morning sun. Make sure to prune dead and crossing limbs every year. Complete a good pruning to allow air movement through the tree. This helps dry the tree out after rain and heavy dew to lessen disease. Having a very shallow root system leaves dogwoods highly susceptible to drought. If we go more than two weeks without measurable rain, make sure to irrigate your tree. If using a sprinkler, do not let the water continuously hit the trunk of the tree, this will have the same effect as volcano mulch! Follow these simple things and watch your tree flourish.
“What you need TO KNOW so you can GROW” series will be taught every Friday from 9:00-11:00 a.m. throughout March. Please call the office for more information and to register for the classes.
If you are having trouble with growing in your home landscape, call the Extension office at (252)946-0111 or email me at firstname.lastname@example.org. There will be a tomato growing class on Saturday April 8th from 9:00 – 11:00 a.m. Please sign up by calling the office. Save the date for April 15 at 9:00 when the Extension Master GardnerSM Volunteers will be having their annual vegetable transplant sale. Until then, Happy Gardening!