Palms   Cold Hardy Palms

The Curious Distribution of the Needle Palm There are reports that specimens of Needle Palm, Rhapidophllum hystrix, have survived a bitter cold snap of 20F (-29C) in Tennessee. Not surprisingly, therefore, some people consider Needle Palm to be the worlds cold-hardiest palm. If you think it holds that title uncontested, you had better think again because there is a well-documented case where Dwarf Palmetto, Sabal minor , survived a very bitter cold snap of 24F (-31C) in McCurtain County, Oklahoma. Given that these two palms are native to the southeastern USA, prefer the same habitats - moist lowlands in part shade, and are equally hardy to cold, you might expect them to have virtually the same natural distributions - yet it is not so. The natural range of Dwarf Palmettois expansive, having its northern limit in southeastern Oklahoma then extending east all the way to the Atlantic Ocean, thence south throughout Florida and west through Texas. Needle Palmbarely makes it out of north Florida, only just stretching into South Carolina, Georgia, Alabama, and Mississippi. If that were not curious enough, even Cabbage Palm, Sabal palmetto , which is leaf hardy to perhaps 10F (-12C) , is far more widespread than is the extremely cold hardy Needle Palm. This hardly seems fair. What might account for these discrepancies? Rhapidophyllum hystrix Sabal palmetto fruit The answer is fruit. Although Dwarf Palmetto and Cabbage Palm are very different in cold hardiness and in height, their fruit is very much the same, and that of Needle Palm very much different. The fruits of Cabbage Palm are produced in large number on branches held away from the tall trunk, and although they are held among the leaves, they are nonetheless quite visible. The fruits are shiny black and the size of currants just the thing for a hungry bird. Dwarf Palmetto, as its name suggests, rarely forms more than a few inches of aerial trunk, yet it send its stalks of shiny black fruit well up and beyond the leaves all the easier for a hungry bird to see. A bird, having eaten the fruit, flies off to digest it. Later, of course, it has to get rid of the hard little seed that was inside the fruit, which it does by regurgitation or defecation, usually some distance away from the plant that bore the seed. In this way, Dwarf Palmetto and Cabbage Palm have their seeds dispersed widely across the landscape. That is all well and good if youre a Dwarf Palmettoor Cabbage Palm, but what of the Needle Palm? Who eats its fruit and distributes its seeds? In order to find out - you must bend down low and inspect the very base of the Needle Palms trunk. Unlike palmetto fruits that are small, dark, highly visible, and offered in profusion, Needle Palmoffers only a few dozen dull, fuzzy fruits the size and color of large brown marbles. They smell like rancid butter, are held very close to the base of the trunk amongst an armory of woody needles, and are hidden behind a veil of leaves. Hardly an invitation for a bird. Needle PalmFruit If birds dont eat Needle Palms fruits, what does? It seems certain that a fuzzy, rancidv smelling, flesh-covered fruit offered near the ground would attract some sort of mammal, perhaps a raccoon, opossum, squirrel, wild boar, or bear. In fact it has been observed that bears do eat and distribute the seeds of Needle Palm. A bear, however, is not likely to disperse seeds as far and widely and easily as would a bird. If that werent bad enough, there is speculation that at least one of the animals for which the Needle Palms fruits were originally meant - is now extinct. This may or may not be the case. If it were true, the extinction would be linked to other events also responsible for the current distributions of these palms.

About seventy thousand years ago, gigantic glaciers of the last ice age covered much of North America. As the immense ice sheets extended south, so too the climatic zones were shifted southwards as cold winds blew off the glaciers. As a result, plants and animals from northern regions extended their ranges southward, and plants and animals from the south retreated even further south. The ice age not only affected the northern hemisphere, but also the southern hemisphere. Between them the glaciers were so immense and extensive that they tied up a significant portion of the worlds water, and ocean levels dropped nearly 400 feet. This caused areas of shallow sea floors to be exposed, thus facilitating the movement of creatures to lands from which they were once isolated. One of the creatures that used such a land bridge to reach North America was man. Although it is true that man may have reached North America before the newcomers arrived ten thousand years ago or so, the arrivals had a lasting impact on the land, for they specialized in hunting large game sometimes very large game indeed. So effective were they in hunting large game that they appear to have hunted it to extinction. Not even huge and imposing creatures such as Giant Ground Sloths and Mammoths escaped this fate. Some people speculate that the Giant Ground Sloth was one of the creatures for which Needle Palms fruit was intended. Even if one of Needle Palms seed disperser did not go extinct after the ice age, the advance of the ice sheets kept Needle Palms range, and those of Dwarf Palmettoand Cabbage Palm, held southwards. When at last the ice age ended and the glaciers retreated, Dwarf Palmetto and Cabbage Palm were able to expand their ranges faster than could Needle Palm, thanks in part, to their partnership with birds. This is not to say that deer, raccoons, and bears do not eat and distribute the seeds of Dwarf Palmettoand Cabbage Palm, for they are known to do just that5. The rather slow spread of Needle Palmin comparison to Dwarf Palmetto and Cabbage Palm may be due in part to the fact that Needle Palm not only doesnt have birds assisting it, but has fewer mammals assisting it too. Thats not the end of Needle Palms troubles, however, for its one known seed disperser, the black bear, is also known to tear apart palms to devour the pithy palm heart. This kills the palm. It is here, however, as strange as it may seem, that Needle Palm may have an advantage over Dwarf Palmettoand Cabbage Palm. Needle Palm protects its trunk with long, sharp woody needles. Even if a bear somehow bypasses this defense and kills the main trunk, Needle Palm has small offset trunks that will survive. Specimens of Dwarf Palmetto and Cabbage Palm, however, have but a single trunk, and when this is killed the plant is killed. After having read this account you may not be surprised to discover that Needle Palmhas been an endangered species. The primary reason for its endangerment, however, is not black bear attacks or lack of seed dispersers. It is habitat destruction. Bears need large tracts of undisturbed habitat to maintain their populations, but land is continuously being developed and habitat fragmented. Furthermore, the very land on which Needle Palm survives is being cleared, filled and developed to satiate an ever-growing population moving to or vacationing in the southeastern United States. Not only are Needle Palms seed dispersers under threat, but Needle palm itself is under threat. It is curious that the cold-hardiest trunk-forming palm in the world should be endangered. You could do yourself and Needle Palm a favor and plant one in your yard. It is a beautiful palm.

Postscript: It has been observed that specimens of Needle Palm planted well outside its natural range produce viable seed. In these cases there is also a seed disperser that is something other than a Black Bear. No Black Bears have been seen or are presumed to exist in Raleighs suburban Jaycee Park! As you might imagine, squirrels, raccoons, opossums, and other furry citizens (perhaps even people?) may be facilitating the spread of Needle Palm.

Rhapidophyllum hystrix