That is Dam, not Damn!

During the drought here in Missouri, my dam that gives me a 1.8 acre pond has developed a leak. The previous owners allowed the dam to become overgrown with trees which is an absolute NO-NO because trees on the dry side push their roots through the dam to get water and then (especially if the tree dies) the roots develop leak paths that drain the pond. The customary advice is to plant grass on the dam and then mow it to kill any trees that sprout. That is difficult when the dam is 15 to 20 feet high and steep. The contractor has suggested that I might want to plant bamboo from my groves of Phyllostachys Aureosulcata onto the dam to protect it from erosion and bamboo would shade out any trees that might try to grow. When it gets to the wet side of the dam the bamboo will stop at the water because submersion of the roots kill it.

So far as I have seen my bamboo is shallow rooting developing a thick mat of rhizomes, but then I have not had occasion to dig vertically into my groves. Any plant that had "deep substantial" roots could be problematic, since that is the problem with trees. Are any of you here aware of the effect of growing bamboo on dams, levees etc., and if so is there any problem. That would include any problems with burrowing wildlife that might find the bamboo to be an excellent habitat if such animals would be likely to show up on the Ozark Plateau of Southwest Missouri. The only animals I have seen around here that like bamboo are cats, Nothing else seems to frequent my groves except the occasional rabbit trying to get away from a dog.

Of course perhaps there is some other variety I should consider besides Phyllostachys Aureosulcata but it will have to be something that will spread rapidly, otherwise the trees and brush will be back in a year or two. Eradicating the bamboo from a dam 200 feet long and 30 feet wide would be a real pain if it ever became necessary so that is a consideration, but hopefully not a likely one. The bamboo would also have the advantage of being a wind break for the pond, and it will provide a privacy screen from the road both of which are important pluses.

A side issue, is there any method to easily maintain a path along the spine of the dam for access purposes. Would simply mowing a path through the bamboo be likely to provide such access across the dam?

Another matter for concern would be if is there likely to be any problem establishing the bamboo on a slope and should I focus on planting at the bottom or top of the slope? If there are no serious problems, bamboo would seem to be an ideal, near zero maintenance, solution to vegetation on earth berm dams.

Please share your insights, as I have limited experience with my bamboo.

Interesting issues. I had to two dams that I had to deal with at my ex's sheep ranch that had similar issues. The previous owners dug through the bentonite that was put down by an earlier owner to line the larger of the two dams, in order to get material to make "a romantic island" for his wife in the pond. What a mistake that was. They had also planted conifer trees on the dam that made for the problems with roots that you describe. That one leaked like a sieve. I cut the trees down and added several tons of bentonite along the pond side and bottom of the dam, but the rodents kept burrowing into the dam (mainly ground squirrels). That was a large dam, running 100 feet, about 20 feet high and wide enough to drive the tractor over with sloped sides. There was another smaller dam by the barn there that was totally overgrown with cottonwoods and willows, and that one was also riddled with rodents (some ground squirrels, but mostly voles). The smaller pond had a spring that fed it and kept it full most of the year and it leaked along the tree roots and rodent burroughs. I cut down all the cottonwoods and willows and I ripped the roots out with a tractor and tried to compact the bottom and dam when it was semi-dry. It helped, but the pond always leaked somewhere (mainly from rodent tunnels dug in summer that flooded out in winter). That place gets a lot of rain; 80 to 100 inches a year in the coast range of central Oregon.

They commonly use bamboo for what you are proposing in Australia and it seems to work fairly well. Bamboos have strong rhizomes that will grow into a grid, The roots will gro from them and create a nice mat to keep the soil in place. The rhizome and root mats are fairly shallow (to about 3 feet deep). Bamboo roots are small and fiberous, and do not get large like tree roots do. Only the rhizomes get large, to about an inch in diameter. There are several types of Phyllostachys that are semi-water tolerant, like atrovaginata and heteroclada that would tolerate wet conditions along the dam top on the water side. They would not grow into the pond, as they are not aquatic plants. Keeping the dam top clear might be a problem as you suggest, as the bamboo would continue shooting from the rhizome grid. You would have to cut them after shooting season in the late spring/early summer. For that reason I would avoid bamboos that tend to shoot all through the growing season, like P. aurea. Planting P. aureosulcata might be a good choice as it is not a super large timber type, it tends to shoot mainly in the spring, and it is a pretty fast grower. I would avoid any of the super large timber types like vivax as they can get too large to manage. As for growing up from the base or down from the top of the dam, I have seen bamboos grow in either direction. I would plant them evenly distributed on the dam face and let them grow out. They will typically grow out 3-6 feet in diameter a year, and fill in over the following years, but the direction of the initial rhizome growth is somewhat random. After a few years you can take divisions and fill in any open areas that they have not grown into. I would suggest planting a lower growing Phyllostachys type of bamboo, one of the intermediate height types, like bisettii, atrovaginata, or nuda, as they only get to about 30 feet high nad they would be more manageable. The other P. aureosulcata types would be good as well as they are shorter, but only P. a. Alata does not commonly revert to the type form from what I have seen in groves planted around here. Planting a short type of Phyllostachys like might also be a better option, but they are rarer types and might not be easy and/or cheap to get. P. humilis is an example of that type. You could also go with a low growing bamboo and consider it a lawn, like Pleioblastus humilis. That typically grows to about 3 feet and is pretty rapid to establish itself. It would not pose the problem as the larger Phyllostachys genus boos on the dam top, and you could just mow it or walk/drive over it. There are other types of Pleioblastus, several types of Sasas and Sasaellas that are short growing and similar.

One problem that you mention is that Phyllostachys bamboo will likely attract burroughing rodents that like to eat the rhizomes. Voles will tunnel through just about anything to get to my bamboo here, especially in winter months. We have many types of voles here. I Googled "voles and Missouri" and I came up with woodland vole, meadow vole and prairie vole, so you have voles there as well. Gophers are a similar problem in California and southern Oregon; there is no getting rid of them either. They love bamboo rhizomes and I see that they have them in parts of Missouri. Ground squirrels are a problem with dams just about anywhere in the US, and will likely be an issue if you plant bamboo or not. I guess that you also have woodchucks there, also called groundhogs. We do not have those here, so I do not know if they like bamboo or not.

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Happy trails...

A couple of things I can add from my experience.

We have groundhogs in the area and they have never taken an interest in eating the bamboo rhizomes.

And until a large tree landed on it, I had a Yellow Groove grove with a path through it that was kept clear just by mowing. I never really worked at keeping it clear, it was just a nice shortcut when mowing the lawn. It was pleasant to walk through and apparently various neighborhood cats liked to sit on the path.

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Southern Indiana. Theoretically the same climate as 'needmore' & 'Eastlandia'.
My Bamboo List.

Wooooo!!!! I have 16 foot tall Moso in Southern Indiana!

That is very encouraging news.

That would probably be shallow enough, but I have been led to believe from other sources that most of the mat for Phyllostachys Aureosulcata would be even shallower than that. The main concern is that it should not penetrate the rocky clay with anythig large below the waterline. The dam has a freeboard of about 3 to 4 feet at high water so I should be ok there and that extends for a width of about 15 to 20 feet.

The information I have suggests that the variety I have would typically go 30 feet and occasionally 45 feet and in a warmer climate and optimum conditions maybe more. However I am at the boundary of climate zones 5 & 6 and my bamboo is thoroughly exposed, and the soil is rocky clay. After 3 years the grove that screens the sewage lagoon and virtually never lacks moisture and is almost surely getting nutrient rich water has just barely made 20 feet. 2 years ago all 3 groves were killed to the ground by -5 F temperatures and high winds for a week in mid winter. It came back with a vengence in spring but given the soil and weather here I think my planting may not quite make typical heights for the variety. If it grows tall on the dam, that would be fine with me as it would be a good wind break and it would also provide a privacy screen and dust screen for that part of the gravel road.

Well I can attest that we have some sort of mole around here that seems to frequent the garden and the bamboo groves, However in neither case have I found any problem for the plants that I can attribute to them. The ground around here stays so hard much of the year, that I think the burrowing critters may actually be helping the bamboo by loosening up the soil so the roots can spread easier, so it may be a good deal for the critters and the bamboo. For all that; whatever burrowing critters we have on the dam, that does not seem to be an issue. and we definitely do not have woodchucks here. The leak seems to have come from the original gravelly bottom stream, which is providing at least part if not all of the problem. The outbreak of water below the dam is well away from the foot of the dam and in the old stream bed the trees may or may not have caused part of the leak path. And the key suspect is the drought causing extensive soil shrinkage to open up a leak path that has now been enlarged by erosion in the passage way. Taking the trees off will be merely a precaution so that they do not become the next problem, most of them are small. The objective for the bamboo is to keep the trees from coming back and keep me from having to mow the steep dam face while re-establishing the wind, dust, and privacy screen. (wouldn't want to skinny dip in sight of the road traffic, dontcha know )

I refer to voles here, not moles. Moles are carnivores that eat grubs and worms, and they make mounds that you can see. Voles are mostly herbivores and remain out of sight for the most part. They are very common throughout the US, but most people have never heard of them. They leave only small holes in the ground that most people miss and they do not make mounds. They live most of the time underground, like moles, and they often use mole runs for their own mode of subterranean transport. Also many people do not notice the damage that gophers and voles do to tree roots and bamboo rhizomes because they are all underground. Having dug many rhizomes myself, I have found vole damage fairly often. I believe that voles and gophers are the main reason that bamboos do not spread rampantly across the USA as they do in other parts of the world. At least that seems to be the case in the western US.

With temps as cold as you list, you are limited in the types of Phyllostachys that you can grow and expect to do well in the open like that. Atro, Bisetttii, Nuda, the Aureosulcatas, and heteroclada are the most cold tolerant. The longer they are in the ground and the larger the stands, generally the more cold tolerant they will become. You can also add wood chips to help insulate the rhizomes in winter, and keep more moisture in the soil in summer. I get the local county road crews to dump wood chips here for free, and I spread them out over my bamboos. Most tree companies are looking for places to dump their wood chips as well, rather than pay fees to dump them at the recycling centers. Phy. bamboos love loose wood chips as a soil topping, and it encourages them to run farther and keep the rhizomes shallower. It also helps keep the weeds down. As you say, in colder areas, the taller bamboos will not grow as large as they would in more ideal climates.

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Happy trails...

My oldest grove, (11 years?) aureosulcata encroaches my dam on the water side, heteroclada 9-10 years, on the same side but at the opposite end of an open area I maintain. The heteroclada holds the soil next to the very long run off trench that starts uphill at my gutters and eventually runs into the pond. I initially planted atrovaginata directly in the center of the dam but the heavy grey clay made it extremely unhappy so I moved it out. The backside of the dam I would have planted but it is so steep and full of rubble/riprap that it is not feasible to dig and plant so again I planted A gigantea on that side for erosion control in a seriously eroding spot that is problematic for me it was eroding so fast.

The aureosulcata grove now is pretty large and growing in the worst soil I have, it started uphill from the dam, has run into it, into the water's edge, down one slope and up another. There are some old pictures of this on my website. It has reached 30' on the largest culms despite really bad soil/care. The heteroclada 'Straightstem' is not as hardy as advertised and one year younger than the aureosulcata it tops out at about 7-8'. The gigantea on the other side is spreading some and does seems to have slowed the erosion although its rhizomes are now exposed on that end - I wish I'd have tried a Phy there instead and am letting 3 other species head into that area.

So the backside of my dam is essentially clear, I string strim it 1-2x per year, it is VERY steep and slick, I'll let any bamboo that gets there take over. A neighbor planted some of my aureosulcata on the backside of his dam and it is a nice grove covering the entire area, I don't believe he has had any problems at all with that.

I mow the space between the aureosulcata and heteroclada as I like to be able to see the pond, both send rhizomes well into the area but the mowing keeps it back and I have a 'grove' of petasites japonica in between them that I'm having to mow back as well.

Forget about nuda or heteroclada, they are not good options in your area stick with bissetii, aureosulcata or Spectabilis.

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Brad Salmon, zone 5b/6 Southern Indiana
Winters -20 to -25C. Summers 30 to 35C , humid. 115 cm annual precipitation, frost free from May through early October. 259.3 meters elevation. Growing 150+ species. http://www.needmorebamboo.com/

ShmuBamboo:
Thanks for the update on voles. I looked them up on wikipedia and can now confirm that that is what we have been calling field mice. Your information and that from Wikipedia, would imply that the damage to my sweet potatos is probably from the voles using mole tunnels, but fortunately the damage is pretty minor and probably requires no remedial action at this time. As for the moles, it sounds like they may be somewhat beneficial in my bamboo groves for loosening the hard clay soil in when it is wet enough and that in turn aids root development for the bamboo. If only the moles would not make such a mess of the lawn. They make it so lumpy I have to slow down the riding mower to protect my old achy back.

Needmore:
Your comments about the success with Phyllostachys Aureosulcata on your dam and your neighbor's is very encouraging. Does it grow right to the water's edge? My pond experiences high water usually just a bit after my bamboo shoots. Last year I transplanted shoots & rhizomes to the side of the pond opposite the dam but shortly after that the water rose to around the plantings and in about 3 days it was falling over and dying.

Given the normal depth fluctuation of my pond (spring high, summer moderate, late summer-fall low) If the bamboo is stopped or killed back to the high water line, I can expect to have a narrow beach around the pond most of the year. If I can carry my plan through, I should end up with a grove about 200 feet long and 30 to 40 feet wide to cover the dam.