The end of summer is usually heralded by the chimes of phones ringing, text messages pinging and emails arriving; all with the same eternal questions: Is my tree dying? Why is my tree dying? Is there anything I can do to save my tree? Unfortunately, by the time we get these emails, it is usually too late. The only solace we can offer is a  health assessment to help home gardeners change their ways to help their future plants thrive. Here are the top reasons plants die and what you can do to try to save them.

Weather Events and Seasonal Climate

Plants grow outside and don’t have the luxury of being able to up and move or come inside to more favorable environmental conditions. They have specific chemicals in their tissues that help them tolerate the season and the weather. But, when it is really hot, really dry or suddenly goes from hot to cold, plants cannot just make the switch. It takes energy to tolerate weather and climate, and depending on the species, some are more or less tolerant. In some cases, for those that are less tolerant, they expend energy trying to survive the climate that they would otherwise use on defending themselves from pathogens.

Grass or Turf Competition with Tree and/or Shrub Roots

So many home gardeners are infatuated with the “sea of turf with islands of trees or shrubs” landscape. The rub comes when you realize that the roots of our favorite grasses can outcompete the roots of our favorite trees and shrubs. Most trees and shrub species do not contend with grasses in nature, so they are not adapted to dealing with them in a landscape. What this means is when water and nutrients are scarce, the grasses will get them first and leave our trees and shrubs struggling. When this goes on long enough the trees and shrubs get weaker and weaker and are less tolerant of stressful conditions. This stress can be exacerbated by damage from lawn mowers and weed whackers consistently damaging tree roots and trunks. All of this culminates in plant decline and death when we get stressful weather.

Improper Planting from the Beginning

There is a right way to plant plants. You can save yourself a lot of heartache, time and money if you get them started the right way. Many trees and shrubs will persist when planted wrong but will seem to suddenly decline or outright die during times of stress. If you look more closely you may see girdling roots or that there is no root flair at the trunk’s base. You want to make sure to break up the root ball when you plant your plants because they will not grow out of the shape of the pot they come in. Also make sure the root flair is above grade, because these roots support the plants. When the trunk is constricted then water and sugars cannot move through the plant as efficiently.

Improper Mulching Techniques

Mulching is an integral part of proper landscape management. Mulch holds soil in place; keeps moisture in the soil; keeps the soil cool in the summer and warmer in the winter; and builds soil organic matter for microorganisms to live in, which can, in turn, help your plants. But, there is a right way to mulch and a wrong way to mulch. There is such a thing as too much of a good thing. Mulch volcanoes are still being deployed in our landscapes and these can be a death sentence to our trees and shrubs. Maybe not in year one or two, but in year 10 or 20, they will be.

Apply an annual skirt of mulch 2-4″ deep around the root zone off your tree, but NOT up to the trunk. You should be able to see where the roots flare out. Ideally this skirt should extend to the drip line, or where the tips of the branches reach out to the sides.

Improper Application of Pesticides

The pesticide label is the law. You should always read the pesticide label before you apply a chemical in your landscape. Not only will it tell you safely how to use it for yourself and non-target organisms, it will also say what weather conditions are appropriate, or not!, to apply the chemical in. Any pesticide can be an herbicide when applied under the wrong environmental conditions.

There are some products labeled as “weed and feed” that can be harmful to “broadleaf weeds”, which can apply to trees! Additionally, if you are trying to kill broadleaf weeds in your turf and you get some of that chemical directly on the roots of your tree you can weaken or out-right kill your tree. The label will tell you how not to harm your trees!

A Combination of All of these Conditions

By the time we get a phone call at N.C. Cooperative Extension there are many things that have gone wrong with a client’s plants. There is rarely “one” thing that has gotten our plants. That is why when we utilize proper planting and management practices we can make sure our plants are off to a good start. Remember, our plants want to survive! It is our job to help them!

Think you need to submit a sample to the Plant Disease and Insect Clinic for diagnosis? Please contact your local N.C. Cooperative Extension Office and we can help you assess your plant issues. You can contact the Lee County Center at 919-775-5624 for more information about diagnosing your plant issues and submitting your PDIC samples.

Amanda Bratcher is the Horticulture Agent for North Carolina Cooperative Extension in Lee County.

Resources:

Earlier article about plant stress: https://lee.ces.ncsu.edu/2022/10/colors-of-a-changing-climate-early-leaf-fall-in-late-summer/

Plant Disease and Insect Clinic Identification and Decision Guide for Cypress Problems: https://pdic.ces.ncsu.edu/decision-guide-for-cypress-problems/

Woody Ornamentals: https://content.ces.ncsu.edu/extension-gardener-handbook/11-woody-ornamentals

Appropriate Use of Landscape Fabric: https://lee.ces.ncsu.edu/2023/02/knowing-better-the-appropriate-use-of-landscape-fabric/