In the last couple of weeks, I’ve had multiple questions regarding trees and shrubs that aren’t looking too hot. These types of calls are common this time of year – it has gotten hot and dry, and plants have fully emerged from winter, causing issues that have been hiding under the surface during the dormant season to manifest as crown or branch dieback. While there are a wide variety of things that can cause dieback, in most cases a little detective work can help pinpoint the issue. Let’s look at a few of the most common causes of dieback and some corrective measures that may help restore the plants to health.
The first thing to do when you notice a plant in decline is nothing. Don’t try and oversaturate it with water. Don’t run out and dump a bunch of fertilizer around it. Many times, these panic measures exacerbate the stress the plant is already under. Instead, I encourage you to give us a call at your local UF/IFAS County Extension Office. We can likely help identify the cause of the problem through a site visit to your property or by you sending us diagnostic photos of the plant with a description of what’s been going on with it – the more information you can provide about the plant and the management practices it has experienced, the better (you can email diagnostic images/information to d.leonard@ufl.edu).
The most common cause of tree/shrub dieback that I see arises from improper planting practices. Most landscape plants should be planted at or just above the surrounding soil level, preferably where the topmost root arises from the trunk. To accomplish this, planting holes should be dug slightly shallower than the rootball’s height and about twice as wide. Planting any deeper than that is probably too deep and can cause problems like trunk and root decay, which lead to crown dieback. Unfortunately, once a plant is planted too deep, it cannot be corrected other than digging up and replanting at the proper depth, which may or may not be possible depending on the size of the tree. Another common issue that can arise after planting is girdling roots. This occurs when plants are grown in plastic containers and develop a root system that circles the inner wall of the pot. If not trimmed, the plant’s root system will continue to grow in this manner, eventually encircling the plant’s trunk, cutting off water and nutrient flow, and leading to crown dieback. Fortunately, this condition can be prevented by cutting, removing, or redirecting these roots at planting.
The next most common cause of plant dieback occurs due to soil disturbance by people. It’s easy to forget but the root zone of trees and shrubs can reach out several times farther than the plant is tall and is easily damaged. Disturbances to the root zone from digging or trenching near trees or compaction from prolonged vehicle travel over the area cause damage that might be slow to appear but can lead to plant decline. If you are doing construction or building near a shrub or tree, try to keep digging machinery as far out of the root zone as possible and avoid repeatedly parking or driving vehicles over the root zone area. Like below ground root damage, trunk damage that occurs from injury by string trimmers, mowers, or animal feeding activity can all disrupt the flow of water and nutrients in plants and prove deadly. There is no cure for this type of damage, so employing physical barriers to prevent damage is key.
The last major stress is environmental in nature and is caused by a water imbalance – either too much or not enough. Dry soil conditions during the planting and establishment phases (first several years after planting) should obviously be avoided if possible – keeping the developing rootzone moist and allowing plant roots to establish in their native soil is critical. Too much water can also cause problems for trees planted in poorly drained soil. Excessive moisture leads to root diseases, which ultimately presents as dieback in the canopy. If planting in an area that tends to stay wet, select a species of plant adapted for that sort of site – some species are more tolerant of “wet feet” than others. While many people expect disease and insect damage to be the cause of an unhealthy plant, they’re often not the biggest culprit and, if they occur at all, are generally secondary to one of the above issues.
Many shrubs can benefit from a little pruning. Choosing what to prune to maintain a plant’s natural look can sometimes be a challenge. Get a few tips on pruning shrubs with cane type growth from UF IFAS Extension Escambia County.
Although a beautiful flowering vine in the late summer and early fall, the non native Autumn clematis can take over an area and escape to natural areas. Learn how to distinguish this plant from the native clematis.
Small debris recently littered area lawns, but these materials are no “trash”. Credit: Adobe Stock
Hurricane Idalia recently tore through the Big Bend area, battering the coast and taking down trees, leaving thousands out of power. While much of the panhandle was safe from the strong winds and storm surge, we still got some gusty weather, and likely had some amount of cleanup to do following the storm. Fortunately for us, this time, it’s mostly a lot of small branches and leaves versus entire trees that our fellow gardeners are cleaning up to the east of us. In addition to being thankful that larger branches didn’t fall here, consider turning those small bits and pieces over to wildlife while collecting your wheelbarrow loads of debris. This is a great opportunity to practice sustainable landscape practices and a few Florida-Friendly Landscaping Principles.
The UF/IFAS Florida-Friendly Landscaping Program has nine principles that it encourages Florida homeowners to practice in their landscape to conserves Florida’s natural resources. Three of the nine principles can be practiced by choosing how you manage the debris that has fallen – #4 Mulch, #5 Attract Wildlife, and #7 Recycle Yard Waste.
A mockingbird enjoys perching at the brushpile. Credit: Adobe Stock.
The first reaction when looking out at your landscape after a storm is typically “Ugh, there’s a lot of stuff to clean up.” We often want to “clean it up” and get it back to a sea of perfect cut grass, or at least sort of nice grass. However, the small branches and leaves that fall can be a great resource for wildlife, can provide mulch around a tree, and letting them rest reduces the need for you to haul all that stuff up to the road and all that goes into picking up, transporting, and processing the material.
The larger branches (four to six inches in diameter and larger) can be used for firewood or a naturalistic bed edging. Otherwise, they can go into a large brushpile. Smaller sticks and branches are perfect for one large brushpile, or, if a large pile doesn’t meet your aesthetic desires, a series of small piles scattered or hidden behind some shrubs is a good compromise. The leaves and really small stuff (branches no larger than a pencil) can be raked up for mulch, added to the brushpile(s), or just left in place to naturally rot away and/or get shredded up by the mower.
Many small, pencil size twigs, along with leaves, can be left in place as a mulch. Credit: Mark Tancig, UF/IFAS.
No matter how you leave the debris, consider how important this material is for all sorts of wildlife. Dead wood supports microbes, fungi, and animals up and down the food chain and even adds to your soil organic matter. While it may not look “clean” to us, those bits of “trash” are gold to many critters, especially small insects that bring birds to the yard. So, during cleanup, consider leaving little treats here and there for wildlife and spend less time hauling it to the road! For more information about the Florida-Friendly Landscaping Principles, visit the UF/IFAS Florida Friendly Landscaping Program website.
The plants you bring home from garden centers and nurseries may look beautiful in your landscape, but they might be invasive species that could escape your yard and quickly spread into natural areas, becoming an ecological and economic nightmare. Florida’s climate makes a cozy environment for a variety of plant species, including the non-native ones. To avoid contributing to the problem, homeowners, landscapers, and plant lovers should carefully select alternative sterile cultivars or other native plants.
The Florida Exotic Pest Plant Council (FLEPPC) created a list of invasive plants that was published every two years through 2019. Professional botanists and others perform exhaustive studies to determine invasive plants that should be placed on the lists. Invasive plants are termed Category I invasives when they are altering native plant communities by displacing native species, changing community structures or ecological functions, or hybridizing with natives.
In 2020 the Florida Invasive Species Council (FISC) took over this task. They began by standardizing invasive species terminology. FISC has adopted the following definitions as described in the publication “Invasive Species Terminology: Standardizing for Stakeholder Education” from the Journal of Extension (Iannone et al. 2020). For details on the new terminology go to: https://floridainvasivespecies.org/definitions.cfm. Words like “exotic”, “alien”, and “naturalized” have been removed from educational material due to individual interpretation concerns. The term “invasive” can only be applied to nonnative species. Many previous informational publications referred to aggressively growing native plants as invasive. This use is no longer accepted. Here are some sample definitions:
Invasive: A species that (a) is nonnative to a specified geographic area, (b) was introduced by humans (intentionally or unintentionally), and (c) does or can cause environmental or economic harm or harm to humans.
Nuisance: An individual or group of individuals of a species that causes management issues or property damage, presents a threat to public safety, or is an annoyance. Can apply to both native and nonnative species.
For a copy of the current invasive plant species listing, as well as other important list of state and federal noxious and prohibited plants go to: https://floridainvasivespecies.org/plantlist.cfm
Many Lantana camara selections are invasive. Look for a sterile selections to prevent unwanted plant spread. Photo by Beth Bolles, UF IFAS Extension Escambia County.
On Wednesday, September 20, 2023, the Okaloosa County Master Gardener Lecture Series topic will be “Plant This, Not That”. This program will introduce the invasive plant species that pose an ecological threat to Florida ecosystems and some alternatives that provide a similar aesthetic value. For more information and to register, click on this Eventbrite link.
Fall is just around the corner, and that means it is time to start kale and collards, root vegetables, and salad greens. Photo by Rachel Mathes.
In spite of this record-breaking hot summer, it might be surprising to realize that we are just a month away from the onset of fall. As the sun-soaked dog days gradually relinquish their hold to the inviting coolness of autumn, the allure of the new season comes into view.
If your thoughts are already conjuring images of vibrant leaves and the anticipation of robust greens and earthy root vegetables in your garden, we extend an invitation to explore our newly revamped edition of the North Florida Vegetable Gardening Guide.
We’ve transformed the guide from a static PDF into a user-friendly website, making it easier than ever for you to tap into its wealth of gardening insights. Crafted by the adept hands of the UF/IFAS Leon County Extension, this guide serves as an invaluable resource catering to both seasoned horticulturists and aspiring gardeners.
Dive into an array of articles, planting schedules, images, and informative UF/IFAS EDIS publications – all thoughtfully designed to address your gardening questions. From the basics of getting started to the finer points of site selection, pest management, fostering biodiversity, soil testing, composting, harnessing cover crops, and mastering irrigation techniques – the North Florida Vegetable Gardening Guide website has it all covered.
For those who prefer a tactile experience, physical copies are available upon request at the UF/IFAS Leon County Extension Office, located at 615 Paul Russell Rd., Tallahassee, FL 32301. A quick call ahead will help you ensure availability.
We’re also excited to announce our upcoming Fall 2023 Backyard Gardening Series, set for September 6 and 13, from 6:00 to 8:00 p.m. on both evenings at the Leon County Extension Office (615 Paul Russell Road).
If you’re eager to explore the art of fall gardening in depth, this series will cover topics like site selection, soil enrichment, effective fall planting techniques, and more, including a hands-on planting activity.
Individual tickets are available for $10 per person if pre-paid online or $15 in cash or check at the door. For families of three to four, pre-paid online family tickets are $20 per family or $30 in cash or check at the door. This registration fee includes both evenings on September 6 and 13 and light refreshments will be provided.
For any further inquiries, please contact Molly Jameson at mjameson@ufl.edu or via phone at 850-606-5200.
