Trees and Shrubs: the "Bones" of Your Landscape
Trees and shrubs, the woody plants, provide the most obvious structure, or the "bones," of the landscape. In Florida we have hundreds of wonderful trees and shrubs from which to choose. The most sustainable action is to preserve the appropriate existing woody plants on your property and when selecting new trees and shrubs, do as your extension agent would advise: "Select the right plant for the right place." With proper selection and maintenance your woody plants will provide shade, privacy, and habitat for wildlife. They prevent erosion, cool their surroundings, and absorb carbon dioxide from the air. That trees and shrubs also add beauty and value to any landscape is a lovely bonus.
Evaluating Existing Trees and Shrubs in the Landscape
Evaluating existing woody plants in your landscape is an important initial step in prudent and sustainable landscape design. Preserving your existing trees, if they are in good health and growing in appropriate locations, is smart. However, large trees that have been weakened by disease, old age, injured roots, or physical restrictions, such as sidewalks, foundations, or roads may need to be pruned or removed before they do harm. Periodic evaluations of this kind help prepare your landscape for hurricanes and other strong storms.
If you have a lot of trees and don't know where to start, seek professional advice from a certified arborist who can help you develop a sound management plan. An arborist may recommend pruning to relieve stress on the trunk. It may take several years because no more than 20% of a tree should be cut out in one year and topping is never a good option. Some of your more dangerous and inappropriately placed trees may need to be removed, but work to preserve as many woody plants in your landscape as you can. Be sure to have the arborist identify all your trees and shrubs for you. Note: Someone who cuts down trees is not necessarily a certified arborist.
Arranging Your Woody Plants
Before you do any purchasing or planting, develop a plan. Ideally you'd create a scale drawing of your lot and plan out different sections to suit your purposes for each area, but a quick sketch may work well for a simple landscape without too much slope. Because some trees are adapted for growing in periodic standing water and some are not, analyze stormwater drainage and other water flows. Before you plant your new trees and shrubs, build rain gardens and French drains that you need to handle most of the stormwater most of the time.
Grouping compatible trees and shrubs together works best in the landscape because this arrangement is most wind resistant and groups of woody plants create good habitat for each other and for wildlife. Your plan should consider prevailing winds, for wind shelter, especially for seaside towns, since the constant onshore winds carry so much salt. Try to imitate how Mother Nature would arrange those plants and then mulch the whole area to create a low-maintenance grove. Trees and lawns don't work well together: the lawn will suffer because it's competing with shallow tree roots for water, and later on the growing trees will provide too much shade. The trees suffer abuse from lawnmowers and string trimmers when they abut the lawn.
This native pinxster azalea (Rhododendron canescens) is a wonderful understory addition to this piney landscape. This shrub is more than 10' tall and 20' wide. It has totally surrounded a pine trunk. Plan ahead for adult sizes when planting trees and shrubs.
Choosing New Trees and Shrubs
When choosing the ideal trees and shrubs for your landscape, plants native to your specific region are the best place to start. Native plants have a well-developed tolerance for Florida's soil, pests, salt air, and its wet and dry seasons. When considering which trees and shrubs will fit into your landscape plans and think years ahead about how much space the mature trees and shrubs will require: vertically, horizontally, and add 30% to the horizontal growth to estimate the root mass.
When purchasing new trees and shrubs, it's best if you can select your specimens from a reputable local nursery that can offer good advice along with its well-cared-for plants. When choosing trees, look for those with one main trunk or those that could be pruned to a main trunk over a few years. For most species, a one-trunked tree will look better in the long run, will be more wind resistant, and require less corrective pruning. Look at the roots: they should be firm and white, and they should not be circling within the pot or rooted into the soil beneath the pot. In general, you'll want a tree or shrub with healthy roots even if it's on the small side. Look for new growth or buds and good green color on the older leaves.
The old advice was to choose the largest trees you could afford, but smaller trees require less long-term care: especially irrigation. They are more likely to survive and may even outgrow larger, more expensive trees within a year or two. (See below for irrigation recommendations.)
This newly transplanted southern magnolia (Magnolia grandiflora) has its mulched watering saucer. My husband and I transplanted this tree five years ago (My Magnificent Messy Magnolias) and since it was the onset of a multi-year drought, I carried many watering cans out to this front meadow over two years. Since its transplant, it has grown at least 6 feet, maybe more. The other magnolia moved at the same time has also done well, but they would have died without all those buckets of extra water.
When planting a tree, dig a hole that is two inches shallower than its root-ball or pot and at least twice as wide: wider is better. Be sure that the center of the hole provides a solid footing so the tree won't sink once it's in place. Most trees have a slight flare where the roots start to spread; size your hole so that this flare will be slightly above the soil line.
Before you remove the tree from its pot or wrap, set it in the hole to check for placement. Prop it up if necessary, and then stand back to view it from all angles: look up as well. You don't want to plant trees directly under or near power lines. Also, go inside and view it from your windows to make sure that your planned location does not block a prized view. Again, remember to consider its mature size.
Only after all this checking, remove it from its pot or wrap and rinse away the old soil in the root-ball. As you place the root-ball into the hole, stretch out its roots. Fill the hole with water as you gently shovel the native soil back into the hole. No amendments to the soil are recommended for trees or palms. It's been shown that compost and other soil-enhancing materials added to the planting hole can discourage the roots from spreading out into surrounding soil. The exception is in a contained bed where roots can't spread too far from the planting site: it this case, enrich the whole bed with compost or other organic material. (See my article on dealing with pot bound plants.)
After the hole has been filled in, press the soil gently in place and create a shallow saucer equal to or larger than the size of the root-ball by creating a berm of soil two or three inches high around the circumference. Lay two to three inches of mulch over this whole saucer area, but never up against the trunk.
If the tree is wobbly and could be knocked over by a gust of wind, staking may be necessary until the roots start growing. Make sure that no stakes enter the root-ball and that no wires or ropes abrade the trunk. Except for palms, stake the tree in such a way that the trunk can bend slightly in the wind: this will enable the tree to build strength in its trunk. Remove the stabilizing stakes as soon as possible, so the tree can build its own strength. But newly transplanted palms should always be held in place firmly for several months while they grow a whole new root system.
Irrigation Requirements after Planting Trees
Unless there is a soaking rain of one inch or more in a week, these irrigation
suggestions are over and above general landscape irrigation.
Each time you irrigate, it's best to water with three gallons per inch of trunk caliper (the diameter of the trunk at six inches above the root-ball of saplings). For example, use six gallons for a two-inch caliper tree. Apply slowly, so all water soaks into the root-ball.
If a tree is two to four caliper inches, the best practice is to water daily for one month and every other day for the next three months. After that, water weekly until the tree is established. For trees more than four caliper inches and for palms, the best practice is to water daily for six weeks; every other day for the next five months; and weekly after that until the tree is established and new growth doesn't wilt during dry periods.
After the initial period, continue to supplement irrigation for your tree during drought conditions for at least a year: two or more years is better for larger specimens.
If you can't arrange for this much irrigation, choose smaller trees for better success. They catch up to the larger specimens within a couple of years and save a lot of time, water, and money.
When your tree has been in the ground for at least three months or just before its next growth period, you can, apply a topdressing of compost or a light application of a slow-release, organic fertilizer around, and outside of, the drip line to improve the soil. Do not use fertilizer during a drought period, though: your new tree doesn't need the added stress of having to support vigorous new growth when water is scarce. Wait for frond growth on palms before applying compost or fertilizer.
Woody Plants Warrant Extra Care: They'll Reward You in Many Ways
Trees and shrubs are the most permanent and prominent landscape plants. Their proper care is a long-term investment. Time spent planning for and choosing the most appropriate trees and shrubs for your landscape, and handling them carefully, will mean greater survival rates, fewer problems, and less work in the long run. Plus growing more trees and shrubs increases the value of your property and is good for the planet.
Sweet bay magnolia (Magnolia virginiana) is a great choice for your landscape here in northern Florida. It's a small tree with leaves and flowers about one half the size of the southern magnolia (M. grandiflora) and will form a thicket if you let it. But one of the best characteristics of this native tree in a wet year like this one is that it will survive in standing water.
- Use the International Society of Arboriculture's website to search for a
certified arborist near you: www.isa-arbor.com.
- The website for the Florida Association of Native Nurseries provides general information on native plants and has a locator for local member nurseries: www.plantrealflorida.org.
- University of Florida horticulture professor Ed Gilman maintains the Landscape Plants website, with detailed information on tree establishment with irrigation details, pruning and other care of woody plants: http://hort.ifas.ufl.edu/woody/index.shtml.
- Professor Gilman has also written some important books: Illustrated Guide to Pruning and with Robert J. Black. Your Florida Guide to Shrubs.
- Florida's Best Native Landscape Plants by Gil Nelson has become a must-have for Florida's gardeners and landscape designers.
Ginny Stibolt moved to northeastern Florida in 2004 and even though she's a botanist and lifelong gardener, Florida gardening was a shock. She started writing The Adventures of a Transplanted Gardener columns for the Times Union newspaper in Jacksonville. This is one of those columns archived here on Floridata.com for your enjoyment. Now she's written three Florida garden books published by University Press of Florida: Sustainable Gardening for Florida, 2009; Organic Methods for Vegetable Gardening in Florida with Melissa Contreras, 2013, and The Art of Maintaining a Florida Native Landscape, 2015. Check out her blog for the latest news and articles: www.GreenGardeningMatters.com