Bamboo and Ohias

[Kiana]

Aloha! We are preparing to plant a privacy screen of clumping bamboo along our property that borders our neighbor. We have some smaller (15-20') bamboo varieties to plant. We have very few ohia on our lot so they are precious, and some of them are on this border. We are aware of their root sensitivity. How many feet away should we plant the bamboo? Thanks for any sage advice!

[steve1]

Tree root systems have been largely misunderstood by architects, landscapers, planners, engineers, and the like, and their lack of knowledge has spread outward to the general community at large.

Imagine a wine glass set on top of a large pizza. That approximates the general proportion of a mature tree to it's underground root system.

Of course there are differences between species, and Ohia is particularly wonderful for Hawaii because its roots grow out and down but take advantages to drop "sinker roots" wherever the opportunity arises. So if they find a small gap they may exploit it and keep dropping clusters of roots until they hit a stable source of water(like a lava tube). It is a wonderful adaptation which allows this pioneer species of tree to survive in relatively raw lava.

So what does that mean for your situation? Simple- just don't cut any Ohia roots. But if that's not possible if you can hand dig with a trowel you are less likely to damage the Ohia than if you use a pneumatic hammer attached to a backhoe. General rule of thumb - don't cut any roots larger than say your thumb, and if you dig by hand you are much less likely to cause serious damage than if you use any sort of power tool. The larger the roots you cut the larger the wound and the higher the chance a pathogen will get it, as well as the damage caused by the partial loss of a root system vital for transporting water and nutrients throughout the plant.

[shave_ice]

I have lots of clumping bamboo and ohia at my place. I'd say the closet they are to each other is 10-15 feet.

[unknownjulie]

What kind of bamboo are you planting? I think I planted Alphonse Karr if I remember that right, in the past. It grew much smaller than advertised in Texas with little water. I'm thinking here they might get larger than advertised (extra water). Anyone have any experience with this?

[MarkP]

Not that I know anything but it would not have occurred to me to be that concerned about the interaction between the bamboo and the ohias. Certainly it would not be like cutting their roots with a bulldozer. If the ohias can live surrounded with strawberry guava they can probably tolerate bamboo. That being said bamboo does tend to overwhelm everything else.

The big issue with bamboo is that it doesn't stay where you put it. There are running varieties that you should never plant. Even the clumping varieties will spread somewhat over the years.

From the descriptions of how aggressive the running varieties can be I wonder where they evolved and where they are NOT invasive. Perhaps it is in cold climates where they get killed back every year.

[Lee M-S]

I was talking to someone who went to China and was shown bamboo plantations; he expressed concern that they were running, not clumping varieties. His host said something like, yeah, they grow really fast and spread; then we harvest them for food and for building. Why would we want a plant that doesn't spread?

Generally, running bamboos can survive in temperate climates; clumping bamboos need the tropics.

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[steve1]

Any reputable bamboo seller in Hawaii would be able to tell you which of the varieties they sell are clumping and which are running, and most reputable bamboo sellers in Hawaii would probably only sell a running bamboo with some sort of disclaimer or warning about any running bamboos they might be selling.
If you find a source for free bamboo you might want to research the variety (if known) or just take a look at the root system to see what it looks like. Ask questions, and if your source doesn't know or care to know any answers you may want to look elsewhere.

[unknownjulie]

ON top of the lava, I"m not sure if the clumping bamboo would spread so much. I think it would need a good amount of soil. They are sort of like a giant clump of daylillies. They spread by tuber/potato type nodules underground. YOu can thin them out, but the root balls are about 2 ft deep in my very limited experience!

[Kiana]

Thanks for the info and input! We are planting Malay Dwarf and Mayan Silver clumping bamboo. I think we can plant a good 10-15 feet away from the ohias, so that is great. They'll look nice together.

[shave_ice]

I have Dwarf Malay. It is a good choice. Doesn't get too big. Coexists with other trees nicely. I actually dug some out because I wanted to replace some of the bamboo with more fruit trees (the previous owners were a little bamboo crazy) and it was fairly easy to dig out, which isn't the case with all bamboos.