SoutheasternSoutheastern PalmsPalms Volume 21-3 1 www.sepalms.org Visit SPS on Facebook Southeastern Palms is the journal of the Southeastern Palm Society (SPS). The society, founded in 1992, is the southeastern United States (north-of-Florida) chapter of the renowned International Palm Society. Members are devoted to growing hardy palms and other subtropical plants. The Southeastern Palm Society also provides to members a quarterly newsletter. Editor and Tom McClendon, St. Marys, Georgia article submissions [email protected] Design, layout, Jeff Stevens, Apison, Tennessee production, mailing [email protected] Address changes, membership and Phil Bennion, Marietta, Georgia payment questions [email protected] Online membership renewal, bookstore www.sepalms.org Rhapidophyllum and Southeastern Palms editors emeritus: ● Will Roberds: 1992–1997 ● Alan Bills: 1997–2000 ● Jeff Stevens: 2001–2008 ©2014 Southeastern Palm Society and/or the authors and photographers. 2 Contents Volume 21-3 July 2014 4 Sabal minor Distribution at the Northern Edge of Its Range Tom McClendon and Hayes Jackson Where to search for native dwarf palmettos on the northern edge of its range in the Piedmont. 14 Let’s Get Reacquainted with Butia Palms Jeff Stevens Understanding the reorganization of Butia palms and looking for more species worth growing in the southeastern United States. Front and back covers: Butia yatay growing in El Palmar National Park, located on the bank of the Uruguay River in Entre Rios, Argentina. The 21,000-acre park was established in 1966 to protect the largest remaining concentration of yatay jelly palms. See article by on page 14. Photo @2014 iStockphoto. 3 4 Sabal minor Distribution at the Northern Edge of Its Range Tom McClendon, St. Marys, Georgia Hayes Jackson, Anniston, Alabama Sabal minor, the dwarf palmetto, is the most widely distributed native palm in North America, so for many palm enthusiasts, it would seem to be the most likely for Southerners to encounter in habitat. Ranging from North Carolina west to Oklahoma and south to northeastern Mexico, Sabal minor in the Southeast is most commonly an inhabitant of hardwood bottomland areas on the Gulf and Atlantic Coastal Plains. These areas quite commonly are flooded in the winter and deeply shaded in summer, so many people never see Sabal minor. Ironically, while most people are familiar with Sabal palmetto and recognize Serenoa repens for its ubiquity on the coast, most people who live near native populations of Sabal minor in the upper Coastal Plain and Piedmont are unaware of the presence of this palm. Along major rivers, creeks, and streams on the Coastal Plain, Sabal minor can be quite common, and large populations exist along nearly every watershed within the range of this species. Figure 1. Sabal minor growing in a typical setting just above winter high water on Cane Creek in Calhoun County, Alabama. All photos accompanying this article were taken above the Fall Line. Photo: Hayes Jackson. 5 Figure 2. Turkey Creek, a tributary of the Little Ogeechee River in Hancock County, Georgia, is home to Sabal minor. A typical Piedmont bluff is in the background. Photo: Tom McClendon. Above the Fall Line on the Piedmont Plateau, however, populations decrease rapidly, and it is rare to encounter Sabal minor anywhere more than 30 miles north or west of the Fall Line in Georgia or Alabama. We sought to learn more about why the sudden drop-off in populations of Sabal minor north of the Fall Line is the case, especially knowing that Sabal minor is among the hardiest of all palms, and reproduces and naturalizes in cultivation far north of its natural range. While there is a positive correlation between higher average temperatures and the presence of Sabal minor (Butler et al, 2011), average temperatures do not drop off rapidly from the upper Coastal Plain to the lower Piedmont, and the entire area is included in USDA Zone 8 on most recent hardiness zone maps. In addition, in Alabama, Sabal minor does occur as far north as the upper Coosa River Valley within a few miles of the Georgia state 6 Figure 3. More Sabal minor in an overflow area in Hancock County, Georgia, well above the Fall Line. This population extends for a half-mile or more. Photo: Tom McClendon. line and within 20 miles of Rome, Georgia, an area typically listed as Zone 7. Discounting temperatures (within certain limits), there must be other factors at work. The two major factors that differentiate the Piedmont and Coastal Plain areas are elevation and soil types. In Georgia at the Fall Line, elevations on the Piedmont (literally, “foot of the mountains”) typically average between 300 and 500 feet, increasing gradually to about 1,500 to 2,000 feet at the base of the Appalachian Mountains. Although average elevations are lower in Alabama, the ranges of elevations there in a small area can be quite dramatic, with areas of Calhoun County along the Coosa River averaging 600 feet above sea level and rising to more than 2,000 feet in the mountains just to the east. In our sampling, Sabal minor does not seem to be present in Georgia in areas that are more than 500 feet in elevation, and in Alabama, about 600 feet. 7 Differences in soil types between geographic regions are much more pronounced. Coastal Plain soils can range from sharply drained sands to silty clays, but the entire region is characterized by the fact that at one time it was submerged by the sea and its soil base, consequently, is sedimentary in origin. While much of the Coastal Plain region in Alabama and Georgia has acidic soils, the subsoil often has a limestone base. In the Piedmont, soil types change abruptly to a crystalline base. Lower Piedmont soils tend to be granitic in origin, while upper Piedmont and Appalachian soils can be either granitic or basaltic. In either case, the predominant soil type is red clay, though there are many soil types present in the Piedmont that range from red clay to sandy loam. An exception to this is the Ridge and Valley province of central Alabama and northwest Georgia. Although typed with other highland regions, like the Coastal Plain region it too was once submerged. Ridges tend to have crystalline and limestone rocks, and the valleys are broad and relatively flat, giving the river valleys a look and feel much like the Coastal Plain. Map 1 (pages 12-13) shows the physiographic regions of Alabama and Georgia and a best-guess range of Sabal minor from the authors. It is likely that the range indicated extends farther north and west than that indicated. The red line on the map indicates the area below which Sabal minor has been located (shown as pink dots). Major river systems that should be investigated further are highlighted in yellow north of the red line. Where it is native above the Fall Line, Sabal minor occurs in very specific habitats. In Alabama and Georgia, Sabal minor most often will be found in dense hardwood bottomland forests along major river drainages. Many of these areas experience periodic flooding, especially in winter, and it is not unusual on the Coastal Plain to see hundreds of Sabal minor with just the tops of their leaves sticking up through running water. However, only rarely does Sabal minor occur in swampy areas with stagnant water. 8 Figure 4. Sabal minor growing with Podophyllum peltatum (May apple) along Beaver Creek in St. Clair County, Alabama. Photo: Hayes Jackson. In the Piedmont, Sabal minor is less likely to be found directly on major rivers, and more likely to be found on smaller streams that feed major drainages. This is because above the Fall Line, large rivers have narrower floodplains and often are rocky or swift with high, steep banks on both sides. Smaller feeder streams, on the other hand, often will have long stretches that more or less resemble a Coastal Plain environment. A summary of suitable habitat is as follows: ● Hardwood bottoms ● Running water (not stagnant) ● Wide, flat valleys ● Silty-clay soils. 9 Figure 5. This smooth, silty, brown clay is the preferred characteristic soil for Sabal minor in the Piedmont. Photo: Tom McClendon. North of the Fall Line, the key to finding Sabal minor is to locate areas that have these qualities. Most streams and rivers in the Piedmont are lined with hardwood trees, so this criterion is usually a given. Running water also is a given, but it is the type of running water available that can differentiate a typical Piedmont stream valley from one that will support a native population of Sabal minor. In the Piedmont, water levels on streams can fluctuate wildly from season to season and even from day to day. The narrower drainage systems of the Piedmont are much more prone to local flooding and often have very sandy “runs.” These areas are not favored by Sabal minor. Where it is found, Sabal minor clearly prefers the flat overflow areas that only rarely flood but remain damp most of the year (Table 1). These habitats become increasingly rare in the Piedmont as the elevation increases, but they are present and when they are, Sabal minor can often be found (Figures 1-4). Most importantly, soil type is very different from the typical red clay of the uplands and flatwoods or the sandy runs of streams. If overflow areas have a dark brown, smooth, silty clay soil (Figure 5), this is strong evidence that the area is a good habitat for Sabal minor. Butler et al. (2011) listed this soil type as preferred by Sabal minor in Oklahoma and is a good indicator for its presence.