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Landscape Development for
Texas Coastal Areas

By Keith C. Hansen, County Extension Agent-Horticulture,
and Dr. William C. Welch, Professor and
Landscape Horticulturist

This publication is designed to aid those most directly affected by the rigors of living in close proximity to the Gulf Coast. Both those within walking distance of the water and residents further inland should find useful information on coping with landscape plant establishment and maintenance.

Landscape development for homes and businesses along the Texas coast can pose unique challenges. Plant establishment, growth, and development are exposed to drying winds, heat, and salt, not to mention insects and diseases. Occasional droughts, severe freezes, and porous, sandy soil can add further obstacles to success.

To compensate for these problems and develop a successful landscape, wise plant selection and careful attention to improving environmental conditions through windbreaks, thorough soil preparation, proper after-planting care, and efficient irrigation practices are essential. There are no hard and fast rules, since conditions vary from location to location. Some experimentation will be necessary, but by following the principles given below, your chances for success will be greatly increased.

Start with a plan

The starting point for every successful landscape is a good plan, preferably on paper and not just in your mind. The process involved in drawing up a landscape design will 1) help you understand, organize, and develop your site for the best use and enjoyment; 2) create a visual relationship between the house and the site; and 3) reduce the overall maintenance level.

A professional landscape architect can greatly assist you in the design process. Help can be as simple as generating ideas for your site to as detailed as a completed blueprint design and help with installation.

The steps involved in drawing up a plan begin with a base plan. The base plan (a scale drawing) includes all the major features of the property, including the house, property lines, easements, existing walks, drives, fences, trees, etc. The base plan should also indicate compass and prevailing wind directions. Once this plan is completed, you can place tracing paper over it and sketch many possible ideas and solutions to your landscape needs and problems.

To help organize your thoughts, list which things are needed to satisfy your requirements and life-style. Study your site to determine where shade and wind protection are needed; where privacy is desired; and which open views to be preserved. Main areas for development may include a childrenís play area, a work or service area, outdoor entertaining, and the area that the public will see and use. Realize the limitations of your site because of proximity to the coast, and plan accordingly.

When considering how to develop the site, donít be guided by a stereotyped concept that landscaping should consist of introduced broadleaf evergreen trees and shrubs, arranged in traditional or formal ways. Be sure to preserve, as much as possible, any existing vegetation, including trees, shrubs, vines, and grasses. These native plants are naturally adapted to the difficult coastal conditions. Every effort should be made to incorporate them into the design wherever possible.

Keep in mind that a landscape is not just a group of plants arranged in a certain way. Design is a problem-solving process. By applying known principles of design to parking, pedestrian circulation, and creation of privacy and outdoor living areas, an environment that is functional and attractive can be developed.



An existing site can be greatly improved through creative placement of attractive structures, such as shelters or gazebos; decks and paths of treated wood, brick, or decorative pavers; a strategically placed sculpture; or a small water feature. This can simplify the difficult job of trying to establish plants in a harsh environment.

Windbreaks

The variety of plants that can be successfully used along the coast increases substantially as protection increases from prevailing wind, blowing sand, and salt spray. Living or construction windbreaks, walls, fences, buildings, or other structures allow many plants to be successfully grown in the lee (area protected from the wind) which would otherwise fail in more exposed locations.

The adverse effects of buffeting winds tend to decrease as one moves away from the immediate coast. For this reason, the plant list in this publication is divided into two zones or belts based on proximity to the coast. This will aid in choosing plants for different exposures.

A windbreak consists of any type of barrier designed to slow down the velocity and redirect the flow of wind. A good windbreak will not create excessive turbulence or wind eddies. Effective windbreaks do not stop the wind but break its forward movement, to slow it down. Solid barriers, such as walls and buildings, create unexpected wind currents and wind tunnels, often with increased velocity and unpredictable direction. Windbreaks composed of living plants allow some of the wind to slowly penetrate, making them more effective.





Examples of windbreak materials include picket and board fences (designed with gaps between pickets), berms, natural sand dunes, and rows or hedges of plants. Temporary windbreaks, made out of snow fencing, 60 percent shade cloth, or other materials, can be used until a permanent screen can be established.

The lee produced by a windbreak is proportional to the height of the barrier. Areas closest to the windbreak will be the calmest, with wind velocity gradually increasing with distance from the windbreak.

The effective zone of protection created by a windbreak is approximately 25 times its height, although maximum-protection wind reduction occurs in a range of 5 to 8 times the height of the screen. Therefore, if planning a windbreak 25 feet tall, the windbreak should be located 125 to 200 feet (5 to 8 times 25 feet) from the house, or area to be protected, for maximum utility. A 10-foot windbreak provides maximum protection to 75 feet and some reduction of wind (about 10 percent) up to 250 feet.



The following criteria are helpful in planning an effective windbreak:

  • The optimum solid space or foliage density for the windbreak is about 60 percent. Fences with 1-inch pickets and 1-inch gaps would meet this condition.

  • Windbreaks are most effective when they extend to the ground. Do not remove lower branches of trees and shrubs.

  • The depth of the planting is important, as it relates to the ability of wind to penetrate. For most evergreen plants, two or three rows are sufficient, but for deciduous plants, four or five rows may be necessary. Rows should be staggered.

  • For small properties, a well-maintained hedge, wider at the base, would serve as an effective windbreak.

Where space allows, wide windbreaks can be designed to lift wind up and away. You can mimic nature by starting with low-growing plants on the windward side, and increasing height within the rows. For example, the first row might be pampas grass or oleander; the second, giant reed or pittosporum; and the third row, tamarisk or other tree species.

When selecting plants for a windbreak, choose only the hardiest. Species occurring naturally along the coast are the best candidates, since these have proven themselves to be adapted to this harsh environment. Observe local landscapes for good examples of hardy plants.

Soil preparation

Nearly every soil can be improved to increase plant health and conserve water. Both sandy coastal soils and heavier clay soils benefit from the addition of large quantities of organic matter, such as shredded pine bark, peat, rice hulls, and compost. This will increase the soilís ability to absorb and store both water and nutrients in a form available to the plants. A 4-inch layer of organic matter, mixed in with the soil at planting time, will aid in the establishment of shrubs and trees. Flower beds and gardens can be amended every time they are replanted.

In sandy soil, strategic planting areas can be modified by incorporating top soil or loam. Make a gradual transition from sand to loam by mixing the first layer of top soil with the sand.

Plant selection

Trees, shrubs, and ground covers should be selected and located with care, since the coastal environment is very harsh and unforgiving. Use locally native plants as much as possible, and keep in mind the effects of proximity to the coast. The more your site is exposed to the wind and salt water, the fewer plants there will be to choose from.

The table in this publication contains a list of plants for the entire Texas coastal area. These plants have been tried and tested, and will grow in most locations as indicated. Care should be exercised in selecting plants for your area, since some plants on the list may be prone to freeze damage under certain circumstances.

The table is broken into two zones or belts, based on proximity to the coast. Zone 1 indicates areas near the shore with the most exposure to wind and salt spray. Zone 2 is where there is more protection from the elements. The table also lists plants according to their cold-hardiness, and identifies them for use on the upper, middle, or lower Texas coast. Use these classifications as general guidelines, since every situation will be different.

Annual flower beds in strategically located, protected areas will provide pockets of color to enhance the landscape. These will need to be replaced several times a year to look their best.

Your local nursery professionals or county Extension agent can help in the selection and description of plants for your area.

Maintenance

Watering

All plants must receive very good care during the first year or two after planting. They must not suffer a setback due to lack of water. A well-designed irrigation system is essential for continued care of the landscape. Sprinkler irrigation is important for lawns, ground covers, and low-growing shrubs, since accumulated salt spray can be washed off the plant leaves. Salt on leaves is one of the most damaging factors for non-halophilic plants, so the ability to wash off salts, especially after storms, is important.

Drip or trickle irrigation is one method to increase watering efficiency in many parts of the landscape. Drip systems apply water under low pressure, slowly delivering water through emitters, bubblers, or spray heads to the root zone of the plants, without waste from over-watering, runoff, or applying water where there is no root system. For areas with high salt content in the water, drip irrigation allows better use of this water, since less salt is applied to the plants. Drip systems are ideal for shrubs, perennial and annual flower beds, vegetable gardens, and for establishing trees.

Seek professional irrigation advice for sprinkler systems, and experiment with available drip irrigation products in small sections of the landscape to become familiar with this water-saving technique.

For details on drip systems and landscape water conservation, refer to other Texas Cooperative Extension information found at the web site

aggie-horticulture.tamu.edu

Mulches

The use of mulch conserves moisture, and aids in establishment and maintenance of plants. Mulch is a layer of material covering the soil surface around plants. Organic mulches, such as pine bark, compost, wood chips, and grass clippings, not only conserve moisture but increase the organic content of the soil as they decompose. Organic mulches need to be periodically replenished. Inorganic mulches include lava rock, limestone, pea gravel, and permeable landscape fabrics (not sheet plastic).

Mulch around plants reduces evaporation of water from the soil and keeps the soil temperature more moderate, thus creating a more favorable growing environment. Mulch also suppresses weed growth which competes with plants for water, nutrients, and light.

Fertility

Most native and many adapted exotic plants require little supplemental fertilization to grow and survive. However, judicious applications of slow-release or organic fertilizers in the spring can help maintain healthy plants which will be less prone to stress or injury due to heat, drought, or cold. Slow-release fertilizers are available over a longer period of time, and are less prone to leaching through porous sand. Lawn grasses will need frequent, light applications to remain vigorous and dense.


Acknowledgment
Thanks to the National Park Service and Dianne Crouch, Master Gardener, for contributing art for this publication.

For a list of plants suitable for Texas coastal areas,
click on the palm tree below.



 


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