The shorter days and cooler temperatures of autumn bring on changes in our shrubs and trees.
Most people expect to see changes in leaf color in deciduous trees and shrubs during fall. But some people become concerned when the leaves on certain evergreen plants begin to turn yellow with the change in the seasons. For many plants this is normal.
Azaleas may lose a few leaves now. These are the older leaves on the branches near the center of the plant. There is no need for alarm by the loss of a few older azalea leaves from now until spring. However, if the younger leaves, those nearest the tip of the shoot, turn yellow or brown there is cause for concern. Poor drainage, lack of water or alkaline soils may cause this condition. Be sure to keep azaleas and other ornamental plants well-watered during dry weather that may occur from now through spring.
Other plants such as gardenias, hollies and camellias may have yellowing leaves now. But as with azaleas, these are the older leaves on the stem near the center of the plant. The mature leaves will drop from the plant from now until spring. This is only the normal aging of older leaves. However, be careful to not confuse this normal process with spider mites, scale, lace bugs, nutrient deficiencies, poor growing conditions or salt injury. Just keep in mind that this normal change in leaf color and leaf drop occurs on the older leaves generally during cooler weather – it’s a seasonal change.
Young red maple with fall foliage. Photo credit: Larry Williams
The leaves of sycamore trees have changed from green to brown by now. Although the sycamore is a deciduous tree, this phenomenon may not be caused by a change in day length or temperature alone. This change in leaf color in sycamores can begin in late summer. Many times, it is the result of sycamore lace bugs feeding on the leaves. By the time the damage is visible, there is little that can be done to correct the problem. However, this problem will take care of itself since sycamore trees will soon be dropping their leaves.
We do have some trees that exhibit beautiful fall foliage this time of year. A few to consider include hickory and gingko for their bright yellow fall foliage, black gum for its early display of brilliant red, purple or orange leaves and Chinese pistache for its late reddish-orange fall show. There are plenty of other good trees to consider for fall color here in North Florida such as dogwood, crape myrtle, Florida maple, sourwood, shumard oak and the list could continue.
Several times each month I am diagnosing shrub and tree problems in Escambia County that are related to the same issue, improper planting. Symptoms of this problem can be slow growth, leaf browning, and dieback. Sometimes under stressful weather conditions like drought, plants completely die.
The trunk was covered with several inches of soil. Photo by Beth Bolles, UF IFAS Extension Escambia County. Shrub stems should never be below the soil level. Photo by Beth Bolles, UF IFAS Extension Escambia County.
This is a difficult sight for homeowners who have invested time and money in a tree or shrub to enhance the landscape. In some cases, the planting issues can be fixed but there are other times when a new plant will need to be installed.
The good news for homeowners is that this is a completely preventable issue. The University of Florida has excellent publications with photos about installing and caring for trees and shrubs. My Panhandle colleagues and I have also shared numerous articles and videos on proper plant installation.
Care must be taken during installation to set your plant at the correct depth. Even if a landscaper or nursery is installing the plant for you, check their work. Make sure the rootball is cut or sliced, it is not set below grade, that any straps holding the rootball are cut after it is set, and proper backfilling occurs without soil over the top of the rootball.
You don’t want to find out later in the season or even year’s later that your plant declined just because of planting problems.
The interest and use of native plants in the landscape in Florida and the southeastern U.S. has increased significantly over the last 20 plus years. There are many benefits for including them in our landscapes including creating a wider biodiversity and enjoying the multitude of support for butterflies, wildlife, and unique color displays.
Choosing the plant species that works in landscape sites requires a few considerations like being adaptable to the site conditions, soil type and preparation, understanding the plant establishment needs, and finding plants regionally to your area.
Bald Cypress with a Saw Palmetto understory. Photo courtesy of Stephen Greer.
Develop a landscape plan that includes addressing soil and site preparation as many landscape sites are altered during the construction phase with the soil being drastically changed. In Florida many sites need soil backfill to raise the elevation for buildings, drive or parking areas to remain above flood challenges. Choosing the right plant for the right place will need to include understanding the plants’ growing environments. Do the plants perform best in well-drained drier areas or moister situations with slight flooding tolerances? Native plants have acclimated to specific soil settings over thousands of years. When selecting the plants for your landscape, perform a site analysis with soil texture, drainage, soil pH, hours of direct intense sun or shade in the growing season, air circulation in the growing area, and growing space available. Doing your homework first can save a lot of money and frustration later. Visit the local nurseries to see plant availability. Just remember many landscape settings do not always match the natural habitats where many of these plants are established in nature.
Native Muhly Grass. Photo courtesy of Stephen Greer.
Soil amendments will likely be needed to improve the soil conditions and provide optimal plant establishment and performance. Most often the soil that brought in is sandy and nutrient poor with little to no organic matter. In addition, the soils are compacted by heavy equipment during the construction phase. These factors can create native plant challenges leading to poor growth and shortened plant life spans. When the soils have been addressed according to plant needs the selected plants can be placed and the fun part begins by following the landscape plan.
With the landscape conditions likely altered with amendments, choose plants that can establish and grow successfully in these often more difficult conditions. Florida red maples (Acer rubrum), Live Oaks (Quercus virginiana) and Sand Live Oaks (Quercus geminate) all can provide shade areas for future plantings. Butterflies attach to and feed on butterfly weed (Asclepias tuberosa) and swamp milkweed (Asclepias incarnata). Butterfly weed does well in well-drained sandy soils and swamp milkweed likes it moist. These are just a few of the many plants out there to consider. Just remember to visit your local nurseries and talk with them about native plants and availability. Enjoy your gardening adventure.
Homeowners are able to select Thryallis as a low maintenance shrub for the North Florida landscape. Learn the characteristics of this Florida Friendly plant with UF IFAS Extension Escambia County!
Lost in the sea of more popular and showy spring-flowering landscape shrubs like azalea, spirea, and the like, is an underused, exceedingly tough, and currently flowering Florida native shrub that is deserving of a spot in your landscape, Walter’s Viburnum (Viburnum obovatum).
Species Walter’s Viburnum (Viburnum obovatum). Photo Credit: UF/IFAS.
Walter’s Viburnum, named for English-born botanist turned South Carolina farmer Thomas Walter, who first described the species in the late 1700’s, is a spring-flowering mostly evergreen shrub/small tree native to the Southeastern United States. In its native environment around hammocks, swamp edges, and near-river forests beneath the understory of canopy trees, Walter’s specimens often grow to around 15’ in height, live for more than 50 years, and spread slowly into loose thickets from their extensive underground root system. After covering themselves in clusters of small, showy, pollinator-attracting white flowers in spring, Walter’s produces small reddish-black fruit that are magnets for birds and other small wildlife in summer.
Though this tough, low-maintenance nature and gorgeous pure white March flower display should have seemingly enabled Walter’s to be a standout in the landscape, Walter’s Viburnum languished in popularity for many years as it didn’t fit into most landscapes in its wild form. Not too many folks in modern landscape situations are looking for a thicket forming, unkempt-looking tree! However, with increased breeding efforts aimed at selecting superior dwarf varieties and the rise in interest in using low-maintenance native plants, Walter’s has rapidly gained market share on traditional flowering shrubs in nurseries and yards in across Florida.
These newer dwarf varieties of Walter’s, including standouts like ‘Mrs. Schiller’s Delight’ and my personal favorite ‘Whorled Class’, only grow 3-4’ in height and make an excellent replacement for more commonly planted small foundation shrubs. Why plant a disease-prone Boxwood when you can have a disease-resistant native dwarf Walter’s Viburnum? Why allow your landscape to be saddled with drab Dwarf Yaupon Holly when you could get the same basic effect AND an awesome flower show by planting a dwarf Walter’s? Tired of having to constantly prune those Loropetalum or Azaleas to keep them from hiding the house? I think you know the answer by now; plant a slow-growing dwarf Walter’s!
‘Whorled Class’ dwarf Walter’s Viburnum in a Calhoun County, FL landscape. Photo Credit: Daniel Leonard, University of Florida/IFAS Extension – Calhoun County.
Both the “wild-type” Walter’s Viburnum and the newer dwarf cultivars are about as low maintenance landscape shrubs as one could want. Though Walter’s normally occurs in shaded understory situations with moist, acidic soils in the wild, it is very adaptable to all manner of landscape situations. The species takes full sun extremely well but will also thrive with shade. It will tolerate very moist soil but, once established, is drought tolerant. I fertilize my Walter’s plants each spring with a general purpose, balanced garden fertilizer to boost growth, but there are many plantings of the species that get by without supplemental fertilizer. Finally, due to the dwarfing nature of the previously mentioned Walter’s cultivars, constant shearing won’t be necessary to maintain a pleasing shape, but they do respond well to pruning when a haircut is needed!
If you’ve been looking to include something a little bit different from the standard spring flowering fare in your landscape but also require your plants to be tough adaptable, try Walter’s Viburnum, especially the cultivars ‘Whorled Class’ or ‘Mrs. Schiller’s Delight’. They’ll be attractive, low-maintenance additions to nearly any Panhandle landscape for years to come! For more information about Walter’s Viburnum or any other horticultural or agricultural topic, contact your local UF/IFAS County Extension office. Happy gardening!
Fall is the season for leaf color changes on many plants, but we are often concerned when we see evergreen plants with brown leaves. Learn what is normal browning for evergreens and when to seek more help from UF IFAS Extension Escambia County.
