Using Native Plants Properly

Follow these pointers to avoid the mistakes commonly made with native plants in the landscape.

By Brightman Logan

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Owner, All Native, LLC.

Published: June 2005 in Ornamental Outlook

A "native" plant, as defined by the Florida Native Plant Society, refers to "those species occurring within the state boundaries prior to European contact."  Any "naturalized" plants are ones that escaped from cultivation or were introduced weeds.

The term "native plant" educes many responses from the horticultural industry: from scorn, to reluctant acceptance, to fanatic appeal.  One thing for sure is that the demand for native plants is on the rise.  For example, more than 30 counties in Florida now have landscape ordinances requiring a certain percentage of native plants to be used.  This trend of utilizing indigenous flora is not happening just in Florida, but all over the United States and in many other countries around the world.

Every year, Florida spends millions in tax dollars to purchase and preserve native habitats throughout the state.  People come from all over the world to visit Florida's unique natural habitats, and most Floridian's can't wait to get out of the city and enjoy the natural environment with which they've been blessed.

So, why aren't we using more of the 2,800 native species that can potentially provide a pleasing palette and sustainable landscapes?  With a landscape emphasis on aesthetics, we sometimes overlook the unique natural features, time of year changes, and wildlife-attracting potential native plants can provide.

Our traditional approach to landscaping relies heavily upon the continued control of stresses that affect plant growth, which does not always provide the best environment for native plant success.  Floridian's now utilize from 40% to 60% of the precious potable water supply to maintain their landscapes.  As populations boom throughout the South, we need to make sure we can sustain our landscapes and protect our natural resources.  A true sustainable landscape minimizes the stressful, limiting factors (sunlight, water, temperature, macro and microelements, pests, and diseases) of each site to achieve a balance.  Native plants have evolved in their respective niches over hundreds of thousands, even millions, of years of evolutionary adaptation and are a natural fit when used properly.  When placed in the appropriate environmental conditions, native plants will achieve this level of success.

Just because a plant is native, does not mean it will work in all landscaping situations.  Listed below are some problematic areas that can plague the use of native plants in the landscape.

Soil And Water pH

The pH of our native soils and water varies all over the state and is one of the key elements that shape the species composition of our native habitats.  Plants adapted to low pH soil and placed in high pH soils are doomed to fail and vice versa.  Parking lot medians that have concrete edging or lime rock underneath are prime examples of higher pH soils.  The pH of the water used to irrigate landscapes can also alter the adaptability of some species.

Site Hydrology

This includes naturally saturated soils as well as too much irrigation.  I've seen many native plum trees planted in the middle of irrigated lawns that perish because of too much water.  I've also seen many wetland species planted into sandy soil in well-drained sites that cannot adapt.

Mulching

Mulches are frequently used improperly in both traditional and native landscapes.  When you look at a lot of native habitats you will notice the absence of a lot of natural mulch (i.e., scrub, high pine, beaches, etc.).  Plant beds mulched too thick or mulch applied against the base of the plant can be detrimental.  Mulches should initially be applied to the area outside of the plant's root ball to enhance soil moisture in the surrounding soil and encourage new root establishment.

Preservation of Existing Soils and Habitat

This can be extremely frustrating in many of our communities because developers are required to add fill to bring elevations above the 50- and 100-year flood zones.  The fill is typically not the good topsoil needed to support native species or many other plants, for that matter.  Working with elements of an existing habitat makes all the difference in the world for a successful native landscape.

Provenance

The original source of a plant stock is important.  Just because a species' natural range covers a five-state area doesn't mean that a South Carolina wax myrtle will perform well in south Florida.  This is evident in redbud and dogwood trees that are grown from native seed or cutting in Tennessee and Texas and then planted in central Florida.  They just don't perform near as well as species from Florida.

Uniformity

Most native plant nurseries were started in response to a demand for plants for restoration projects and, as such, did not put an emphasis on the uniformity of species demanded in our traditional landscapes.  We are now seeing a lot of native plant selections enter into the marketplace that fit this need.  Most of these are natural selections found in native habitats that exhibit a special feature (bloom, fall color, mutated size) or a combination of many attributes.  The genetic diversity of natural selections is the preferred choice, as opposed to hybrids that could cross-pollinate with surrounding natives and negatively affect their gene pool.

Lack of Knowledge

Landscape architects, designers, landscapers, and land planners need to educate themselves about specific plants.  Plant specs need to be more realistic (many natives don't fit traditional specs).  More concern needs to be taken for the proper establishment and maintenance, which is vital to long-term success.  Ask questions of native plant association members, attend native plant conferences, and visit web sites dedicated to natives.

The art of applied native plant landscaping is continually evolving.  Critical research is lacking.  With continued research about native plant physiology and adaptability, the plant palettes, methodologies, and understanding will continue to advance.

So Why Should You Plant Natives? There are more than 2800 species of native plants found in our state, and about 1 in 12 of our native plants are endemic- meaning the species occurs naturally only here and nowhere else.  The use of native plants gives the look of rarity, provides an at home feel, and promotes pride for the state of Florida. The demand for native plants is growing as the public becomes more concerned, more educated, and more focused on water conservation. Although there is the preconceived notion that natives are not attractive and appealing in today's landscapes, it is by no means true.  Many natives are fragrant, brightly colored, provide seasonal color changes, known for their hardiness, and are generally insect resistant.  More importantly, natives are becoming horticulturally enhanced-meaning the selection of cultivars' growth are developed and controlled for landscape use. They create a landscape that looks natural, functions with minimal care, feeding, and watering.  Using natives eliminates the monotony and lifelessness of the typical urban landscape setting and restores the habitat that these urban landscapes take away from wildlife. Not only do they provide aesthetic appeal to the landscape, they provide a habitat for wildlife and reduce the amount of chemicals used in a typical non-native landscape.  Protecting and promoting Florida's biodiversity has become the goal of many landscaping projects.  Native plants provide a natural habitat for butterflies, birds, and other wildlife.  Florida's flora includes one of the largest assortments of spontaneously occurring species in North America.  Several species of exotic plants have become invasive or have strong potential to invade, destroy, or irreparably alter Florida's most precious natural areas.  This problem is not only a focus in Florida, but it is evident all around the world as more and more countries are pushing a trend to focus on native landscapes. The use of natives rather than alien plants enhances conservation of our natural resources and usually ensures a low maintenance and sustainable garden.  Conservation of soil and water is the guiding principle behind using native plants in a landscape.  Florida experiences seasonal droughts, water shortages, and a variety of other environmental stresses.  The benefit of native plants is that they are adapted to these natural conditions.  Using plants that are not adapted to Florida’s environment will set the stage for perpetual maintenance, lead to depletion of soil fertility, and have the potential for invasive weeds to spread and disrupt nearby and not-so-nearby natural areas.  As we use fertilizers to sustain the life of alien plants, we disregard the consequences that they inflict on the environment.  Fertilizers are a primary cause of increased nitrogen levels found in our water supply.  This increase in nitrogen can cause uncontrolled growth of some species of plants and essentially choke out the native growth and also take over some open areas.  Nitrogen run-offs into our protected estuaries is becoming an increasing problem for the state of Florida.  Already, it has been linked to toxic red tide outbreaks becoming more and more intense and creating a longer duration in the harmful algal blooms that have killed many marine creatures and driven away tourists from many of Florida's beaches.  Scientists studying red tide at the request of Lee County claim that pollution run-off and poor water management practices are at the root of the problem.  Florida is constantly pumping more and more nutrients into the Gulf which continues to feed the blooms.  Degraded water quality and marine kills have been reported in the Florida Bay area for more than two decades and conditions continue to worsen.  In the spring of 2004, 170 bottlenose dolphins washed up dead on Florida's shores with extremely high levels of red tide toxins throughout their bodies. Overfertilization of single-family lots and other residential properties is considered to be a greater culprit to rivers and streams than a same-sized agriculture operation. Education towards the use of native plants is key to solving this and other key issues.  Native plants promote water conservation, eliminate the need for fertilizers and pesticides, provide a natural habitat for wildlife, and help to preserve the native beauty of Florida for future generations.  References: Scientists: Red tide not going away. 2005. Chad Gillis, Sun-Herald.com Sierra Club launches campaign to combat red tide. 2004. Frank Jackalonewjn, Sierra Club.org Florida's Best Native Landscape Plants by Gil Nelson Florida Plants for Wildlife by Craig N. Huegel Association of Florida Native Nurseries             Fast Facts About the Benefits of Urban Tree Planting Bay Surroundings Fall 2005     ·        While necessary for plant life, an overabundance of nitrogen starts a chain reaction that ultimately leads to the loss of seagrasses, a vital habitat for many living organisms. The majority of excess nitrogen in Tampa Bay is a result of stormwater runoff and atmospheric deposition and trees help reduce these problems. A single mature tree can intercept approximately 500-750 gallons of stormwater per year, depending upon its size, species, and rainfall characteristics. Trees reduce the volume of runoff stormwater by absorbing water in their roots and leaves, and then slowly releasing this water into the air or soil.   Trees absorb many nutrients from their environment, including nitrogen, from stormwater. In Tampa Bay, ongoing studies indicate that 40-50% of the nitrogen in the bay falls from the sky as atmospheric deposition.  Each tree in an urban area can capture up to 10 pounds of pollutants per year, including nitrogen dioxide, sulfur dioxide, carbon monoxide, ozone, and other particulates. Healthy urban tree canopies can lower city temperatures by up to 20°F. The Center for Urban Forest Research reports that two, strategically planted trees may reduce energy bills by up to 25% by the time that the trees reach 15 years of age. Trees add 5-19% to the value of a home. Businesses benefit too…a survey taken in Georgia found that 74% of potential patrons preferred shops with trees and landscaping, and that they would be willing to pay 12% more for the products they purchased at these locations.     Invasive Plants in Florida It is estimated that more than 1.5 million acres of Florida’s remaining natural areas have become infested with non-native plant species.  Hydrilla, which is Florida’s most widespread invasive exotic aquatic plant, covered approximately 65,486 acres of public waterbodies in 1996.  At least 45% of the invasive non-native plant species found in Florida were imported for ornamental or agricultural reasons.  Additionally, approximately 39% of the worst invasive plant species are still commercially available for sale and continue to spread and take over Florida’s landscape. For a complete list of plants that are considered invasive to Florida, visit Florida Exotic Pest Plant Council. Reference: Department of Environmental Protection Pictures courtesy of Impact.ifas.ufl.edu