River cane, an American bamboo

Guest post by Alex Rajewski (@Rajewski)

When you picture a forest of bamboo, the last place you might think to find it is in the southeastern United States. Although the majority of bamboo species are found in Asia, River cane (Arundinaria gigantea) is the only* species of bamboo native to the United States. During my master’s degree research at the University of Georgia, I studied the propagation and genetics of this species, so I’m more than a little enamored with River cane.

Alex Rajewski River Cane.jpg

Alex by a small canebrake of River cane in Athens, Georgia

As the name suggests, River cane likes to hang out along riverbanks and streams, where it can form very large and very dense bamboo forests called ‘canebrakes’. When Europeans first surveyed North America, they often found these dense canebrakes running for several kilometers along rivers. Ecologically, these canebrakes are very important. Canebrakes have dense roots that make them very effective at controlling erosion, and they also work to absorb nitrogen fertilizer runoff before it can enter and pollute streams. There is also some evidence that canebrakes form a unique habitat for many birds and insects.1

Beyond its ecological value, River cane is botanically fascinating! Unlike many other plants, River cane takes an extremely long time to flower. Some observations suggest 30-40 years between flowerings. When River cane does flower though, it does it with style. Often the entire canebrake will flower simultaneously, produce hundreds of thousands of seeds, and then die off. The seeds look like green rice, but unlike rice, they must germinate immediately or die. After the flowering, birds consume many of the seeds, but the sheer number of seeds ensures that enough will germinate and restore the canebrake.

What exactly triggers the plants to flower after decades of growth is not yet clear, but researchers do have some insights into how the plants coordinate their flowering en masse. Each seed that germinates not only grows a leafy aboveground shoot but also many underground stems called rhizomes. These rhizomes spread out and send up new shoots along their length. This means that many (or even most2) of the shoots in a canebrake are from one individual plant. Additionally, all the seeds produced by a flowering event are the same age and are closely related. This combination of having very a few dominant individuals, who are related and of similar age makes flowering together easier, though no less interesting.

Of course it can’t be all milk and honey, River cane is critically endangered, though not yet federally protected in the US. Many scientists and private citizens are currently rising to the challenge by working to increase awareness, promote ornamental use of River cane, and enact conservation of canebrakes.

*The exact number of US bamboo species is (surprisingly) hotly debated, and numbers between one and three depending on how you define a species. River cane is almost always the primary species in the genus, but Hill cane (Arundinaria appalachiana) and Switch cane (Arundinaria tecta) are commonly mentioned.3

References:

  1. Platt, S. G., Rainwater, T. R., Elsey, R. M. & Brantley, C. G. Canebrake fauna revisited: additional records of species diversity in a critically endangered ecosystem. Bamboo Science & Culture 26, 1-12 (2013).
  2. Kitamura, K. & Kawahara, T. Clonal identification by microsatellite loci in sporadic flowering of a dwarf bamboo species, Sasa cernua. Journal of plant research 122, 299-304, doi:10.1007/s10265-009-0220-1 (2009).
  3. Triplett, J. K., A.S. Weakley, and L. G. Clark. Hill Cane (Arundinaria appalachiana), a New Species of Bamboo from the Southern Appalachian Mountains. SIDA, Contributions to Botany 22, 79-95 (2006).

 

About the author: Alex Rajewski is a recent transplant to the University of California, Riverside, where he is pursuing his PhD. His current research focuses on the evolutionary and genetic forces that created fleshy fruits in the nightshade family. Follow him on twitter: @Rajewski.

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One thought on “River cane, an American bamboo

  1. That is very informative and amazing at the same time. Have you witnessed this flowering?
    I am an architect and I have taken an interest in River cane ever since I was in college near Moundville Alabama on the Warrior River. We were searching for inexpensive ways to build homes for poor people. I simultaneously became enchanted by the origin of civilization and the organic urban planning of the largest native city in the South East 1000 years ago. They did not have any local stone to build with but they had plenty of chalky wet clay, many long cane breaks throughout the river and tributary bottom land, and the surface was covered with palmetto bushes for easy roofing. The wood dig holes around 16″ to 20 ” o.c. in the form of their outside perimeter, then they wood mount 4-5″ diameter eastern red cedar poles, then they would weave the river cane in and out of the poles and then pack it with the clay.
    I then started growing a 25′ tall privacy hedge of bamboo along the property line when a guy bought the vacant lot uphill from me. I could never effectively build a privacy fence that tall.
    Yes, Chinese bamboo may be faster and taller but you can not tie Chines bamboo in a knot without it breaking. The U.A. Archaeology students recently found the remains of a river cane floor mat in an ancient Moundville home. It was woven around the perimeter post in a high tension manner. it is amazing that the natives had wall to wall carpet 1000 years ago. River cane is still one of our best native cordages. Would there be a way to breed our high strength American Cane with the fast growing oversized Bamboo from China? I could make some great structures with little money. Could I do a graft? Would cross pollination work between these species? Thanks for your education.

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