RUNNING BAMBOO

My rants have gotten too long so from now on they will contain no more than 2,000 words.

I originally intended to cover running bamboo in my September 2023 post Doing Something About the Infection but, because it is physically and behaviorally different, I decided a stand alone treatment was a better idea. For example, the subjects of that previous post (burning bush and Callery pear) are both dicots and, unlike them, running bamboos are rhizomatous and rarely if ever produce flowers or fruit (i.e., their reproduction is almost exclusively asexual). Further, most people are surprised to learn that running bamboo's clonal selfing is via tenacious, one-inch (or more) diameter, "woody," leptomorphic rhizomes OR that bamboo is a grass, many of which are problematic as ornamentals. Running bamboo control is even more challenging than Japanese knotweed (Fallopia japonica) another nasty, often banned, rhizomatous invasive exotic species.

While I like the look a stand of bamboo provides, it should be responsibly grown. The plant needs space and, before you consider releasing this formidable woody (i.e., infecting your property), consider this: the recommendation to prevent lateral migration of these impressive invaders is at the very least a vertical in-ground barrier of 60mil (1/16 inch) thick high density plastic buried 24 inches below grade! Anything less is potentially breachable -- under or through! Yes, through! Bamboo rhizomes are frightening -- the leading tip is pointed and hard. Concrete and steel will not suffice as a barrier over time. And vigilance is required . . . the rhizomes will attempt to get past any barrier seams and they can and will try to grow over a solid in-ground barrier. I suggest most people would suspect a paved walkway or road would impede the migration of running bamboo -- often NOT! See pic above. Moreover, it is not unusual for bamboo shoots to pierce asphalt! I have witnessed this in Indianapolis. And, if what you just read was not enough to dissuade you, the lateral underground migration can be 20+ feet a year!

For a decade I have been attempting to control a running bamboo infection along an intermittent stream at my Indianapolis property using both mechanical and chemical means. I suspect the bamboo got to my place having washed in from somewhere upstream. Hydrochory is a common means of migration for plants associated with waterways. The banks and bed of that stream also were infected this way by the yellow flag iris (Iris pseudoacorus). Several people have compliment me thinking that I planted the iris and the running bamboo. I DID NOT. The area bordering the stream was a thicket of weedy woody species when we arrive in 2010. Only after I cleared the Asian bush honeysuckle, dead ash, mulberry, wild grape and box elder did I notice a couple of small bamboo stems. I should have annihilated it back then. I thought I had time -- turns out I DID NOT. It was increasing underground. Regarding the control, challenging is a gross understatement. I am losing the battle!!! For example, since bamboo is a grass, the stems are hollow except at the nodes, so I cut new growth spring sprouts just below a node and used a turkey baster syringe to fill the internodal chamber with XS Roundup to no affect! I learned that chemical control requires multiple applications over several years, is variably effective, and take caution, glyphosate is a nonselective herbicide. I have spoken to several property owners who have tried to herbicide their bamboo infection away without success. Moreover, trying to control bamboo with fire has the same result one gets with sugarcane (Saccharum spp.) or giant reed (Arundo donax), the fire only burns the leaves. The rhizomes are untouched and the stalks subsequently develop new leaves. Many grasses and grass communities are fire dependent -- the burning is rarely a killing action, more of a cleanup and conversion action.

I have discovered that taking advantage of the plant's behavior provides one a means to both control the stand and potentially eliminate the population entirely (i.e., by starvation, preventing photosynthesis and the subsequent food/E storage) and this method requires no herbicide. Merely mow and/or snap the emerging stems in spring, but it takes 2-3 years and vigilance. I have used the starvation method to eliminate Asian bush honeysuckle that had been cut and then produced new growth. Again, without needing to use an herbicide.

Periodic inundation actually seems to promote growth of the bamboo which is not surprising given the cane's preference for living along and near waterways. Further, without a barrier, the rhizomes will continue to extend out underground for several meters from the edge of the above ground (visible) colony. By the way, I cull the brake (the collective noun for cane) of its biggest stems which I trim and use variously, especially as support stakes. The culms can be more than an inch in diameter. The leaves will commonly die back over winter -- turn light brown and fall off. New leaves and shoots are produced in spring. The production of the new shoots is referred to as shooting. One could also consider using the tender and fast growing tips as a vegetable, but of course not if an herbicide has been used. Moreover, all bamboos are monocarpic (i.e., they produce one crop of flowers and seeds before dying) but if you are waiting for the dieback that accompanies bamboo flowering, think again. I have never seen yellow groove bamboo flower in the Midwest, it could take a century or more and, even if it does, there is no certainty the entire colony would perish. Some plants (moss to flowering species) rely primarily or exclusively on asexual reproduction, even with the resulting evolutionary disadvantage of limiting genetic diversity.

I will not be surprised if running bamboo is the subject in a yet to come damage from trespass lawsuit. In fact, I eagerly anticipate it happening. A lawsuit that could force a prohibition as well as a warning label for running bamboos and a few other plant species. I foresee the defendants including a property owner (where planted), a retailer (the company that produced and distributed the plant) and perhaps the installer (if other than the property owner or retailer). There are numerous examples of such trespass . . . lots of potential plaintiffs. All that is needed is a funding source and an attorney interested in environmental law to prosecute and help set the precedent. Consider it as a necessity to protect us from ourselves -- too many of us are incapable of making rational decisions re plants and otherwise. If you could witness or talk with someone who has had to deal with running bamboo YOU WOULD AGREE. Think of it as legislating wisdom (i.e., curtailing foolishness, preventing an environmental mistake with long-term consequences that dwarf an individual's want). Moreover, the lawsuit should establish that the removed plants are a biohazard and need to be disposed of accordingly . . . any rhizome pieces left in ground will regenerate. Furthermore, the remediation is difficult, causes severe disturbance (will require heavy machinery), takes time and will be expensive. The pics 2-4 above show running bamboo which invaded and grew under a house with the bamboo sprouting up through the walls and floor causing >$100K of damage!

Some (perhaps most) of the running bamboo I see in central Indiana is yellow groove bamboo (Phyllostachys aureosulcata) a cold hardy Chinese native. I say perhaps because, despite being big plants, exact identification can be challenging, often requiring a rhizome be unearthed and examined. The genus alludes to the leafy inflorescence (again, you will likely never see this), while the species name refers to the yellow groove on the stems. The cultivar 'Spectabilis' is especially appealing (top pic). Besides the distinctive pigmentation another characteristic of this species is a crook near the base in about 10% of the stems. In central Indiana the stems can get 16-18 ft. tall and about an inch in diameter -- bigger further south and smaller further north. Running bamboos are an appealing plant that can be grown in a container but putting it in the ground is fraught with negative consequences, even if contained. If you are foolish enough to use it, know that for best effect I would recommend a bed >100 sq. ft. but DO NOT consider without installing an adequate barrier. Moreover, the plants are slow to establish -- it may take several years -- but once they do, watch out. And BE ADVISED that running bamboos already are prohibited by ordinance in some communities (e.g., Bloomington, IN). If property owners there are unwilling or cannot remove/destroy the plant population the city can and will do so, with the expense added to the owners tax bill. I saw yellow groove bamboo offered for sale at Rosie's on the north side of Indy last year. They know better. It is irresponsible to do so and I have told them as much, and more than once. Rosie's also continues to offer the highly invasive winged burning bush. Give them an ear-full next time you are there and feel free to tell them the Mad Botanist told you to do so. Good / responsible gardening requires occasional constraint -- both the suppliers and the customers.

Before all the nonnative haters start using bamboo as yet another raison d'être pure, the native giant river cane (Arundinaria gigantea, another type of large running "woody" grass) is almost as impressive and just as challenging to control. The canebrakes, which can be 12+ feet high, are dense and almost impossible to walk through. Sadly, we have managed to destroy most of the special and extensive aboriginal canebrakes (est. >10M ac.) that existed in the southeastern U.S. Small stands of river cane can still occasionally be seen in the southern 1/3 of Indiana. These brake (cane thicket) communities are fascinating and were important for both cultural and ecological reasons. My longtime buddy and super botanist ecologist Mike Homoya gave an interesting, and at the same time depressing, talk at a native plant society meeting a few years back. He noted that in southern Indiana we had canebrakes covering a mile square which were completely obliterated and the land converted to agriculture -- tilled acreage.

In closing, let me enlighten you with these facts. Canebrakes and old growth riparian forest were the prime habitat for the Carolina parakeet. No doubt the destruction and reduction of the brakes contributed to the demise of this beautiful and noisy yellow-headed bird. Sadly, the last captive Carolina parakeet perished in a Cincinnati Zoo in 1918. The species was officially declared extinct in 1939. Another casualty of too many humans and ill-advised behavior -- habitat loss and hunting. Legislation in the early part of the 20th century banned the commercial hunting of plumage birds like herons and egrets, but the magnificently pigmented Carolina parakeets were unable to survive the pressure and change. By the way, it was actually a parrot, not a parakeet, and we now know there were two subspecies. The midwestern subspecies disappeared first by about the start of WWI. Before their demise these special gregarious birds were common, living in pairs and often flocking. Notice in the above Audubon painting that the birds are feeding on one of their favorite plants (poisonous cockleburs) which they ate with impunity. Seems no other animals could do this. This ability may have been yet another example of acquired chemical defense against being eaten, like the monarch butterfly / milkweed connection. Alas, the birds need not worry any longer :(