What happened to my dogwood tree?

Published 4:25 pm Friday, March 15, 2024

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Their graceful lying branches with creamy white flowers mark the beginning of spring so beautifully. As I see them preparing 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 the flowers, they are modified leaves called bracts. I thought you should know in case you find yourself on Jeopardy!

Dogwoods are a wonderful tree in their native environment. They complement the understory of a forest and do not 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. Dogwoods do not adapt well, however. Does this mean that we shouldn’t grow them – absolutely not! We always need to think, Right Plant, Right Place!

A dogwood is well adapted to growing in slightly acidic, moist, but well drained soil. As an understory forest tree, it enjoys protection from heat, cold, and the harsh winds 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 tree is not a long-lived tree to begin with, averaging around 80 years in ideal conditions.

There are only a handful of disease and 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. However, root rot does often kill dogwoods in the coastal plains. These are phytophthora and armillaria root rots that can typically be traced back to soils staying saturated for long periods of time.

The only insect that will do considerable damage is the dogwood borer (Synanthedon scitula). These holes can often be found near the base of the tree. 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 frass (sawdust) at the base of the trees to see if you may have borers. More often than not however, it is things that we can prevent, that I find are causes of death in dogwoods.

There are many cultural problems that a tree will be subjected to growing in a lawn. First is improper planting. This is true for most any tree that I am called out to take a look at.

We homeowners, and often many landscapers, do not plant trees correctly. When planting, the first thing to do is prepare the site which includes getting a soil sample and taking a long look at the sites drainage.

Next, the first root on the tree should be planted no more than one 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 that water will not pool over the top of the roots when it rains. The soil will settle over time as rain and irrigation occurs. 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, causing the roots to hit the side of the container and then to grow in a circle. If these roots aren’t pruned off 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 seasonal highs and lows and conserve moisture in the soil by lessening evaporation. A good layer of mulch will keep annual weeds 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 a 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 it out after rain and heavy dew to lessen the instance of 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 few simple things and watch your tree flourish.

If you are having trouble with growing in your home landscape, call the Extension office at (252)946-0111 or email me at gene_fox@ncsu.edu. Check our website or the Beaufort County Master Gardener Facebook page for upcoming classes and events. Mark your calendars for our Totally Tomatoes class April 13 and our Extension Master Gardener Plant Sale April 20. We will have over 1,000 vegetable seedlings for sale from 9:00-11:00 or until supplies last. Until then, Happy Gardening!