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Conocarpus Erectus (Florida Buttonwood)

By Mary Madison, USA; and Jean Waldberg, USA
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This article originaly appeared in "Florida Bonsai" the magazine of the Bonsai Societies of Florida.
Vol XXII, No. 1, pg 4-10.
Reprinted with permission of the publisher of "Florida Bonsai" magazine.

Some of the greatest bonsai in the world are those collected specimens which reflect a struggle for survival against the overwhelming odds of the ravages of nature The appreciation of any collected bonsai specimen is enhanced by the realization of this struggle for survival.

The Florida buttonwood, Conocarpus erectus, is unique in its struggle in that it is not indigenous to South Florida and has had to survive not only frost, floods and violent winds, but storm tides and man, too! It is also unique in that it has received aid in its struggle from alligators!

Florida is of recent geological origin, and the primary habitat of Conocarpus erectus, the Everglades and Florida Keys, is thought to be only about 5,000 years old. Current thinking is that the plant species did not evolve in the area but in the Caribbean Basin and was transported to Florida by tropical storms.

In Trees of South Florida, Dr. Frank C. Craighead, Sr., considers the Everglades "one of the most formidable of our natural environments" and states further "Nowhere else in all our land can be found so many adaptations between such a complex of physical factors and varied biota."

The primary factors in the development of vegetation types are soil, water (fresh or saline), drainage, and elevation. In South Florida some of these factors are measured in inches! A difference of two inches in average water level results in profound changes in vegetation. Buttonwood occurs where peat have built up about ten inches above mean sea level.

Black, red and white mangroves and buttonwoods cover much of the low coastal areas of the South Florida shoreline. On the landward edge of the Saline Mangrove Zone (a crescent shaped area at the southern tip of the Florida peninsula) is the Buttonwood Embankment or Buttonwood Levee. This embankment impounds the freshwater swamps of a three county area (Collier, Dade, Monroe) thus separating normal tidal waters from the impounded fresh water.

Fresh water plant associations of saw grass, spike rush, buttonwood strands, bay heads (tree islands of swamp hardwoods), willow heads and cypress domes thrive in the marl and peat of these freshwater swamps. The Coastal Levee, prior to white man's activities in the area, was occupied by stands of mature buttonwoods and other tropical hardwoods. Now prairies of shrubby growth and immature buttonwoods occur in this area.

Within the Saline Mangrove Zone are Saline Buttonwood Islands or Strands. Buttonwoods form almost pure stands on the islands that have built up a peat elevation of one foot or more. These areas are one and one-half to three feet above mean tide but are submerged by storm tides.

The Coastal Prairies also have Buttonwood Strands. Hurricane Donna in 1960 deposited a layer of marl mud on the coastal prairies which furnished an excellent seed bed, and buttonwood has now taken hold on these prairies.

The general climate of the area is sub-tropical in nature with temperature means varying around 15 F between summer high and winter low; however, at periodic intervals frosts do occur. Buttonwood and all three species ofmangrove are severely damaged by 30 F, with buttonwood and white mangrove most susceptible. Frost will "cut back" top growth of buttonwoods to persistent root systems which then form dwarf communities of many stemmed shrubs.

Rainfall is seasonal with 60% to 80% of annual precipitation occurring from May through October.

The effects of hurricanes are many: many plant species are brought to the area, trees are sheared off completely by tornado-like winds, stripped of branches, completely defoliated and uprooted, rootlets are broken by the swaying of the trees and trees are flooded by the highly saline tidal waters which rush across the low elevations of South Florida.

The highest mortality of vegetation from hurricanes occurs in low areas on which a deposit of impervious marl two to six inches deep is deposited by high tides. This causes an oxygen deficiency to the rootlets of completely defoliated trees which cannot then survive.

Although mangroves can tolerate a salinity of 40,000 ppm (parts per million) of sodium chloride, buttonwoods are usually destroyed where this concentration is held for a few months. Buttonwoods can tolerate a salinity of 1,000 ppm and can exceed this if the flood of storm tides is followed by heavy rains which dissipate chlorides.

Alligator trails are an important factor in the flow of water through the Everglades and to the formation of Buttonwood Strands. Tearing the roots of mangroves with their snouts and tails, the alligators serve to keep the mangrove creeks open. The decline of alligators has allowed mangrove roots to grow and accumulate debris, and many former mangrove creeks are now Buttonwood Strands.

Alligator nests built of plant materials two to three feet high and six to eight feet wide are "taken over" by buttonwoods when abandoned by the alligators.

Buttonwoods have been a commercial commodity in Florida. The very hard wood was used to make buttons, while buttonwood charcoal was a primary source of fuel prior to the introduction of kerosene. Buttonwood hammocks were cleared for producing charcoal 200 years ago and as recently as 40 years ago. One cord of buttonwood produced 10 bags of excellent charcoal.

Conocarpus erectus, the Florida buttonwood, obviously has evolved very successfully and is a vital part of the ecosystem of South Florida. Those buttonwoods thriving in Everglades National Park are untouchable and many are unreachable except by the hardiest explorer.

But what of those "easily collectible" specimens in the other areas, notably the Florida Keys?

The stunning beauty of the sunlight shimmering on the multi color tropical waters, the fresh ocean breezes, the graceful flight of the sea birds as one travels the Highway-That-Went-To-Sea is never to be forgotten. When the traveler views the twisted, torn remnants of a railroad destroyed by a hurricane, they begin to realize the rigors and hazards of life on these unique islands.

Buttonwoods are found throughout the keys, generally in the Mangrove Zone. Although usually on elevations a foot or so higher than the mangroves, buttonwoods are also found in areas exposed only at abnormally low tides.

On the upper keys, buttonwoods growing in pockets of soil and accumulated debris tend to have leaves larger than those plants on the lower keys which are growing in rocks with very little soil. Silver buttonwood is found on the lower keys, too.

Collecting can be done throughout the year; however, during the spring and summer months the plants apparently suffer little or no shock. The collector, though, will have to endure heat, mosquitos, deer flies and sand flies in profusion. During the fall and winter months, the plants do suffer shock and are slower in recovery.

Although inevitably some plants are lost, if kept well watered for three to six months, injured trees may recuperate. For the collector, the fall and winter months are far more pleasant, but throughout the year, there are hazards: ants, scorpions, innumerable species of snakes, poisonwood and even crocodiles. The latter will not bother you, if you don't bother them!

The most appropriate tools are a small pick, hatchet and lopping shears, plus, of course, plastic bags.

After trudging over the rocky, razor-sharp pinnacles of coral rock and/or through knee deep muck, one arrives at a collector's "heaven on earth" a forest of naturally dwarfed buttonwoods, complete with tiny leaves, driftwood and natural jins by the score - possibly never before seen by the human eye. There they are, growing in the hot sun, sprayed by salt, torn by winds, flooded at each tide, growing in what seems to be solid rock. Instinctively the tools are dropped and one pauses for a quiet period of contemplation.

When the tools are picked up again, there is a new respect and admiration for these individual living "miracles" of nature. With discretion and discrimination, the collector selects a tree or two.

The books must now be forgotten. One cannot root-prune or take a fine ball of roots out of almost solid rock. Clip the roots, get as much as you can, cut back the top and, if there's a pool of water nearby, set the specimen in it until ready to leave. Otherwise place it in an opaque plastic bag, spray some fresh water on it and, if possible, set in shade.

If unable to pot immediately upon arriving home, set buttonwoods in buckets of water. If left in water for extensive periods of time, they will form new root systems. Buttonwoods are truly incredible plants.

For best results, pot collected trees into bonsai containers as soon as possible. Experience indicates greater success with buttonwoods if all drastic pruning both of top and roots is completed when potting immediately after collection. If little or no root system is obtained, completely defoliate the tree! The critical time for buttonwoods seems to be when repotting once established in a container, rather than when initially potting.

The new root system will sprout at the very terminal of the larger roots and not in a general root ball at the base of the tree. Cut the long heavy roots back initially or the entire root system which develops in the container will have to be sacrificed at repotting. Occasionally a more complete root system can be developed by scoring heavy roots at the base and applying root stimulator to the scored area.

Potting soil mixture for buttonwoods should be organic and can be either rich black potting soil or a mixture of soil, gravel and calcined clay particles.

Watering is the key to success with buttonwoods! Remember, the natural habitat of buttonwoods is moist, damp and even wet areas. To encourage growth of a root system, or if the buttonwood in not recovering well from the shock of collection, submerge its pot in water. Never allow the plant to dry out completely!

Buttonwood is susceptible to cold and should be protected at temperatures below 40 F to 45 F In South Florida it will tolerate 35 F if sprayed with water constantly through the cycle of evening drop in temperature through morning rise of temperature.

The driftwood or dead wood which is so striking can be left untreated. The forces of nature which created this magnificence seem to have made it impervious to decay. If desired, after the plant is established, it can be treated chemically to bleach and further preserve the driftwood.

Although in South Florida there is little experience with buttonwood as indoor bonsai, it would seem an ideal candidate. The plant can be treated almost casually, requiring little maintenance as long as it receives plenty of light, a humid atmosphere and plenty of water.

As has been shown, Conocarpus erectus, Florida buttonwood, is essentially a hardy species. The very factors essential for adaptation for survival in nature are the primary factors in its successful adaptation to pot culture and bonsai. These same factors also create those extraordinary specimens so highly prized by those who have acquired them and which are admired by all who are privileged to view them.

Botanical Notes

Conocarpus erectus

Common Name: buttonwood, button mangrove.
Small tree with gray and brown fissured bark.
Leaves: Alternate, simple, elliptic, leathery, light-green 2" to 4" long with wavy margins.
Flowers: Small greenish to purplish in color globose heads in narrow clusters 6" to 8" long throughout the year.
Fruit: Red-brown, globular, button-like cones 1/2" in diameter. Propagation: Seeds, cuttings and easily collected.
Salt tolerant, insects and diseases not known to be a problem.

Conocarpus erectus var. sericeus

Common Name: silver buttonwood.
Tree to 40'
Bark: Dark gray, thin, peeling in long strips.
Leaves: Margins entire, apex round or pointed, light gray, fuzzy 1" wide, 2 1/2" long.
Flowers: Red-brown, cone-like 1/2" in diameter throughout the year.
Seed: Many, red-brown, winged 1/ 8" diameter.
Range: Native only to Florida Keys.
Propagation: Seeds, cuttings and easily collected.
Salt tolerant, susceptible to freeze, grows on rocky limestone formation, but faster on marl or peat.

Laguncularia racemosa

Common Names: white mangrove, false mangrove, buttonwood.
Tree to 60' high, diameter 20", wood is dark, yellow-brown, heavy, hard and strong.
Bark: Astringent properties, high percentage of tannin.
Leaves: Opposite, smooth, thick, leathery, oblong rounded at ends 1" to 2" long, dark green on top.
Flowers Opposite on central stem, 1/4".
Fruit: 10 ribbed, hard, flattened pod with two thin ridges or wings about 1/2" long. Contains single dark red, thin-walled seed.
Range:: Cape Canaveral and Cedar Key south over Florida Keys.
distributed through Antilles, Central America, South America and Western Africa.

Bibliography

The Florida Keys, Bill Ackerman, Florida Department of Agriculture 1957.

Forest Trees Of Florida, 10th ed., Florida Division of Forestry, 1972.

Man In The Everglades, 2000 years of Human History In the Everglades National Park, Charlton W. Tebeau, University of Miami Press.

Native Trees & Plants For Florida Landscaping, Charles S. Bush and Julia F. Morton, Bulletin 193, Florida Department of Agriculture, 1969.

Selected Trees For Florida Homes, C. A. Conover and E. W. McElivee, Bulletin 182A, Florida Co-op Extension Service, University of Florida, 1973.

The Story of The Chokoloskee Bay Country, Charlton W. Tebeau, University of Miami Press, 1955.

Trees of Everglades National Park and Florida Keys, George B. Stevenson, Natural History Association, 1969.

Trees of South Florida, Vol. 1, The Natural Environments and Their Succession, Frank C. Craighead, Sr., University of Miami Press, 1971.

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