Indian River County Extension Service
1028 20th Pl, Suite D
Vero Beach, FL 32960
April 3, 2002
FOR RELEASE: 7 April 2002
Daniel F. Culbert, County Extension Director
This past week I visited a condominium that needed some help choosing plants. They wanted to stabilize their oceanfront dune. My visit suggests there may be others who need information on plants that are capable of holding that line - our beachfront pioneers.
Todayís column will suggest some of the site requirements for these Florida Yard plants, and offer a few examples that are the right plants for this special place. Information is based on Florida Sea Grant Extension publications, Florida DEP Botanist Kathy Burks, and local native plant grower Sharon Dolan.
The condo I visited has recently replenished their dune with new sand, and they were left with a naked sloping cliff that faced the ocean. To hold this sand in place, they were advised to sod the slope with Bahiagrass. This was not a bad suggestion at first glance, because grasses can grow rapidly, and Bahia will make it through drought better than most grasses. But the long-term survivability of this sod is doubtful, as Bahia will not tolerate the salty water nor the alkaline beach front soils. So what should we do?
With such a steep slope, my suggestions to the condo association were to first hold the sloping sand in place with a groundcover cloth staked over the sod. Then, select a variety of coastal pioneer plants that are capable of rapid growth and insert them through this cloth. Once a vigorous root mass is in place, additional plants can later be added to recreate a more natural environment. Because this was a deep slope, this was a difficult situation to work with.
The coastal beach environment is harsh, and the only plants that can survive are those that have some hearty characteristics: they must be drought tolerant, be able to withstand blowing sand, laugh in the face of salt water, and can grow their roots rapidly in alkaline soil. This is not the place for expensive palm trees or exotically colored flowering shrubs or bushes. So what plant choices might work in such a locale?
Finding a source for these plants will involve some homework. Digging up dune plants from natural areas is against the law. Fortunately, there is an organization that can assist. The Florida Association of Native Plant Nurseries produces a list of plants that can fit these specific needs. The pioneer plants listed below reflect some of those plants that are the right plant for the right place, and they are commercially available.
Sea Oats, Uniola paniculata is the number one choice for a beach erosion prevention plant. The coarse waxy leaves are blue-green in color, and in late spring they shoot up the familiar flowerstalks with seeds that look a bit like oats. The roots of this plant can penetrate several feet into the coastal dunes. Donít collect the seed to grow your own sea oats without a permit, and donít collect the stalks for dried plant decorations either -you risk hefty fines. There are several nurseries in the state that specialize in dividing container-grown clumps and producing high quality plants ready to transplant into your Florida Dune.
Beach or Dune Panic Grass, Panicum amarulum, is another coarse grassy plant that will be effective in dune stabilization. This perennial has leaves that reach 3/4 inch wide, and they are more blue green in color than Sea Oats. (Many coastal plants have thick waxy coatings on their leaves to minimize moisture loss, and this gives them a "blue" tint.) A similar grass
is Bitter Panicum (P. amarum) that has green foliage. A wispy brush like seed head produces lots of seed that can germinate in the moist parts of the summer, or the clumps can be divided.
Saltmeadow Cordgrass Spartina patens is a softer, finer leaved grass that is a bit shorter than the others; it tops out at three feet. It is seen more often where the soil is shelly rather than sandy, and will not be able to do as well if blowing sand covers its crown. Two other species of Spartina are available, but they are not as well adapted as coastal pioneers.
Seashore Paspalum or Salt Jointgrass Paspalum vaginatum is a low creeping grass that can from a mat. It is not a native grass, but its drought and salt tolerance and sand holding abilities make it a desirable dune plant. Some recent finer-leaved selections released by the University of Georgia are now being sold in our area as lawn plugs or sod. These grass cultivars will need intensive care that will not be found on the dunes; ask for the coarser kinds for this purpose.
Beach Bean, Canavalia rosea is a creeping perennial vine with thick fleshy stems. The pink to purple sweetpea-shaped flowers grow in clusters and will produce 6-inch long pods. Three oval leaflets are about 4 inches across, and help trap sand and feed this deep-rooting native plant. Seedling or seed can be used to start this plant.
The Railroad Vine Ipomea pes-caprae is fairly common on the open beach area. It is easily recognized by its long rapidly growing stems, some of which can be 75 feet long. Two parallel stems running over the sand will show you why it is called the railroad vine. Thick rubbery leaves are four inches wide and shaped like a goatís footprint. Pink to purple flowers open up to form a colorful 4-inch round bell any time during the year. Beach Morning Glory Ipomea imperati is a similar vine that has shorter runners and smaller yellow-colored flowers. Our area is near the southern edge of this speciesís range, and it appears a bit more cold tolerant than the Railroad vine.
Beach or Seashore Elder Iva imbricata is a clumping spreading upright mass of succulent stems and thickened one-inch leaves. The clump can form a mound up to 4 feet high, and easily traps blowing sand. Inconspicuous flowers produce lots of small brown seed, but the plant can also grow from stem cuttings. Similar in appearance to this plant is Sea Purslane, Sesuvium portulacastrum, but it is more spreading than upright. It looks very similar to the fleshy-leaved Portulaca weed that is found in our lawns and gardens.
Sea Grape Cocoloba uvifera is the most likely candidate for a woody plant that might survive closest to the ocean. It is kept dwarfed by ocean breezes, but when grown at the furthest edge of the pioneer zone it can be 15 to 20 feet tall. It may be joined by the Saw-tooth palmetto, Serenoa repens, where pioneer plants give rise to the scrub zone. Thick fibrous palmetto roots trap and hold shifting sands, and can form impenetrable thickets several feet tall.
The appearance of these last two plants is quite well known to most local residents. What is less well known are the rules of the Florida DEP, which say that no more than one third of the height of these plants can be removed when pruned. In the case of Sea Grape, they cannot be cut back lower than 6 feet. So, if a room with a view is important, consider how big these plants will grow before obstructing a desired vista.
If the need for colorful flowers on your dune planting is just too great, two wildflowers could be attempted. Blanket flower Gaillardia pulchella is a slowly spreading perennial with yellow to red colored daisy-like flowers. And the more familiar colorful addition to coastal dunes is the Beach or Dune Sunflower, Helianthus debilis. It will not do well if it gets too much water. Neither of these plants will produces extensive roots needed to stabilize sandy slopes, but they will add a splash of color on our Indian River Beaches.
Floridaís Sea Grant Extension Service and the USDA Soil Conservation Service have determined relative growth rates, establishment times and researched the propagation methods and planting guidelines for these plants. Our office can guide you toward these references and provide a native plant nursery list if you are ready to plant these pioneers in our Florida Yards.
If you need additional information on beachfront plants, visit our Master Gardeners or call or stop by our office. For those with other questions about Florida Yards, our office holds Master Gardener Clinic hours at the Extension office (1028 20th Place, Suite D, Vero Beach) every weekday morning and most afternoons, Wednesday morning at the City Commission Chambers at Sebastian City Hall, and the first Saturday of the month at the Environmental Learning Center. Our phone number is 770-5030, and you can e-mail us at email@example.com .