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original document location: http://edis.ifas.ufl.edu/EP007 Native Trees for North Florida 1 Alan W. Meerow and Jeffrey G. Norcini2
In recent years, the subject of native plants has taken on new significance in Florida horticulture. Some of the reasons for this include the loss to development of natural areas in the state, coastal deterioration due to disturbance of native vegetation, and concern about water use to support exotic landscapes. The introduction of exotic plant pests that naturalize and, in some cases, out-compete native species, has become of great concern in various parts of Florida. Fortunately, relatively few of the hundreds of exotic ornamentals that have been introduced into the state fall into this category. Many counties are considering landscape ordinances that require a percentage of native plant materials be utilized in all future developments. Several have already implemented such ordinances. This will result in a need for wider availability of native plant materials. Woody landscape plant producers, landscape designers, and home gardeners in Florida need to become informed about and prepared for the production and cultural needs of this type of plant material. Native plants are not new to the Florida nursery industry. Many native trees are already well-represented in the inventories of north Florida nurseries. Such "staples" of north Florida horticulture as cabbage palm ( Sabal palmetto ), southern red cedar ( Juniperus silicicola ), live oak ( Quercus virginiana ), southern magnolia ( Magnolia grandiflora ), and dogwood ( Cornus florida ) are all native to the state. Arguments For The Use Of Native PlantsA number of claims both for and against the use of native plants have been proposed. Some claims made for landscape performance of native plants are:
Energy efficiency. Because they are adapted to our soils, temperature, and rainfall patterns, native plants require less irrigation and fertilization. This argument can be true only if several factors hold, namely that the right native has been chosen for the site to be landscaped, and that the original soil profile and hydrology at the site have not been altered. All too often, native topsoils have been removed and water flow patterns have been changed during development. If such is the case, an attempt to recreate the original composition of trees and shrubs may fail or require a great deal of extra maintenance to succeed. Low maintenance. Native plants are resistant to pests and diseases in Florida because they have evolved under constant exposure to these organisms. Plants do not evolve in isolation. The resistance to pests and diseases can sometimes be as much a factor of interactions between the plants that make up a vegetational association as the individual genetic resources of any one particular species. Native plants may not demonstrate any "advantages" in this respect when planted in disturbed sites or mixed with species not usually associated with them. And certainly, as with any new planting, regular care during establishment is necessary. Ecological-Educational factor. Their landscape use preserves endangered natural resources of the state. This argument is perhaps the best one for wider use of native plants. Florida's continued rise in population does place enormous pressures on our native vegetation. The educational benefits of native plant landscapes, particularly in teaching new residents about our state's natural bounty, have great value. Arguments Against The Use Of Native PlantsClaims made against the landscape use of native plants include:
They are slow-growing. Plants differ in their growth rates as much as in any other characteristic. Native plants range as widely in this category as exotics. In many cases, slow growth rates can be improved with increased nutritional levels during production. Cultivar selection and evaluation programs also improve slow growth rates. In some situations, slow growth rates may be advantageous; for example, slower growing trees will require less pruning to control size or prevent interference with power lines. They are unattractive. Native plants include attractive, showy trees like southern magnolia (Magnolia grandiflora) and more homely species such as wax myrtle (Myrica cerifera). Both have a niche in landscape situations. Many native trees have a subtle beauty all their own. Their propagation is difficult, therefore plants are expensive. Certain plants become widely available in the trade in part because they are easy to produce. This knowledge comes about through research, in both the private and public sectors. It is true that many choice native species are difficult to propagate successfully, but on the whole, this is due to lack of research efforts and unavailability of information. They are generally unavailable. Even with the limited knowledge of native plant propagation, there are currently over fifty nurseries listed by the Association of Florida Native Plant Nurseries, with a combined plant inventory of over 500 species. A number of native species are already represented in the inventories of many nurseries. Landscape Situations For Native TreesIn certain landscape situations native plant usage is particularly desirable. These include:
New development with pre-existing vegetation in which a tree canopy has been retained. Showy exotics look out of place in landscapes in which a great deal of pre-existing native vegetation has been spared the bulldozer's blade. In such developments, the use of additional native materials to "naturalize" the area can create a more harmonious and aesthetic effect. Environmentally sensitive areas, such as the coastal strand, barrier island, and wetlands. These areas have suffered a great deal of mismanagement and shortsighted development. Many of the plants native to these environmentally sensitive areas are particularly adapted to the specialized conditions found there. The use of these native plants may actually help to slow further deterioration of some of these environments. Public areas (parks, beaches, nature centers). Native plants should be a priority in public areas for their environmental and educational value. Site Factors To Consider When Choosing Native SpeciesCareful consideration to the characteristics of the planting site must be used when choosing native plant materials for landscaping. First, some concerns relating to the past history of the site must be answered.
What was the original vegetation of the area? This knowledge will give an indication of which native plants will perform best on the site. Assuming that the answer to the next question is no, native species that once grew in a given location are likely to do best when replanted in comparison with species from very different types of native vegetation. Have the native soil and/or hydrology been modified? During development, topsoil is often removed, and original drainage patterns disturbed. Fill soil of very different quality may have been brought in to replace the topsoil removed. If such is the case, it may be impossible to re-establish the same species that once grew on the site, or else require a great deal of maintenance to do so. Secondly, considerations must be paid to the present condition of each planting site. If fill soil was added during construction, its composition can vary over a short distance. Does the site accumulate standing water? What is the soil type: muck? white sand? coral rock? Is there salt spray exposure on the site? Will the landscape plants have to be integrated with turf, and possibly be subjected to turf-oriented irrigation practices? All of these factors will influence the degree of success with which particular native species will perform in a landscape. What landscape functions need to be fulfilled? Certain aesthetic factors come into play when choosing materials natives, just as they do with exotic plant materials. Should the trees primarily provide shade, barrier effects, or beauty in the form of flowers of fruit, or is low maintenance the main criterion for plant selection? The size of the lot also restrict the use of some species whose mature dimensions require a lot of space. Planting Native TreesPlanting native tree species is no different than planting exotics. Consider first the time of year the tree is to be planted. Containerized trees can be planted any time. Trees that are balled-and-burlapped can be planted in winter and spring. Bare-root trees should be planted only in the spring.
Amending the backfill soil is not recommended. The crown of nursery stock should be situated at the same level in the soil as occurred in the field or the container. Large masses of circling roots in container stock should be slit lengthwise to stimulate lateral root production. It may be necessary or desirable to reduce top growth; this should be accomplished by thinning out (removing one or several, well-distributed branches at their point of origin), rather than heading back (cutting all top growth back to approximately the same level). Thinning cuts will preserve the natural shape of the tree. The trees should be well irrigated after planting, and a 2- to 4-inch mulch of organic material is recommended. A top-dressing of a slow-release fertilizer can be applied within the dripline of the tree before the mulch. If it rains on a regular basis in the first six months after planting, additional watering may not be needed during that period. If not, periodic irrigation will be necessary. Generally, supplementary irrigation is required during the first year after planting. The frequency of irrigation (weekly, to several times per week during the first month) will depend on temperature and the water-holding capacity of the soil. Irrigation frequency can be reduced in successive months. Generally, the production of new growth is the best indication that a tree is becoming established. Supplementary fertilization one or two times per year may be desirable, at least during the first year after planting. Using The Native Tree Selection TablesThe tables which list native tree species suitable for use in north Florida will help in making the right choices for various landscape situations. These lists are by no means a complete inventory of the tree species native to the northern part of the state, but is representative of those native trees that have proven themselves in the landscape, are available from nurseries, or are judged worthy of wider use and availability. The two tables list the characteristics and environmental requirements of various native trees.
Special attention should be paid to environmental factors such as soil pH and light requirements, and drought and salt tolerances. Drought tolerance refers to Florida conditions only and should be interpreted as follows:
In general, the best guide to determining which natives to use in a landscape situation is to become familiar with the species in the wild, and also to observe which species are performing well in nearby landscapes. Understanding the characteristics of the natural communities in which a particular species grows will provide insight into the cultural conditions necessary for that species to thrive in the landscape. Obtaining Native PlantsNative plants should not be transplanted from the wild, unless the plants face destruction from development. Superior clones in native populations should be identified where possible, and nursery stock propagated vegetatively or by seed from them. The Florida Native Plant Society (FNPS) regularly publishes a bulletin called The Palmetto containing horticultural information on natives. You can obtain a copy by writing to:
c/o Cameron Donaldson (The Palmetto editor)The best source of information on obtaining Florida native plants is Native Plant and Service Directory which is published by:
P. 0. Box 434There is a place in Florida horticulture for both superior exotic and native ornamentals. The "native plant movement" should be looked upon as an impetus to add to the diversity of landscape materials at our disposal in Florida.
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