Running Bamboo – Mitigation Methods

Bamboo is seductive in myriad ways.

It’s graceful, fast-growing, disease-resistant, and (deceptively) low maintenance. And the running — as opposed to clumping — varieties spread … often faster and further than we’d like.

Most running bamboos have a three-year establishment cycle.

Year one: it sulks
Year two: it awakens
Year three: it runs.

All bamboo, whether running or clumping, has a nose for water. Running bamboo, in particular, can sniff out water and charge headlong, underground, in its direction. Its rhizomes — the lateral roots that send up shoots yards away from the mother plant — will not be denied in their quest for moisture. If you’re regularly watering, say, a red-twig dogwood (Cornus alba cultivars, et. al) 15 feet away from a grove of running bamboo, you can bet the rhizomes will reach the dogwood by the third or fourth year, especially following wet winters.

For this reason, placement is the optimum criteria for bamboo and any adjacent plants. Running bamboo is best grown in a strong container (i.e. not terra cotta, or plastic) placed on top of a thick cement paver. If you still insist on planting it in the ground, it’s best to dig a 30-inch (at least) deep ditch entirely around the plant and monitor for rhizomes aiming to run. Cement berms work for awhile, as do resin boards sunk three feet deep around the plant, but I’ve seen rhizomes go over, under, and, with cement, THROUGH barriers. The best way to monitor runaway rhizomes is to use the ditch method.

So, after all this, let’s say you go ahead and plant a variety of running bamboo in the ground with no ditches, containers or barriers. Before four years have passed, your neighbor reports seeing bamboo shoots emerging from the ground on his side, close to your mutual fence — in the middle of his prize azaleas.

Now what?

Assemble these tools:

1) heavy gloves and safety glasses/goggles
2) spade
3) trowel, or hori-hori or cultivator/hoe hand tool
4) crowbar
5) reciprocating saw

This is a specialized job but can be done by most homeowners with the proper tools and a bit of surplus energy. It helps to undertake the task on a cloudy day that’s not too hot; spending a dusty weekend sweating, on your knees, crowbarring three-inch diameter bamboo rhizomes isn’t something I’d recommend to a friend.

Don’t soak the ground in an attempt to make digging easier. This just makes the dirt expand, and (obviously) become muddy and, actually, more difficult to work with. Too much water also helps any rhizomes you don’t find to spread faster. Sprinkling a bit of water on the work site tends to help keep the dust down, so there’s that. Some may also find a dust mask helps deal with airborne particulate matter when digging in dry dirt.

Find the end of the rhizome. It’s usually just beyond the most recent sprout. Dig down, gently, using the trowel, until you locate the rhizome, then work around it with the hori-hori or crowbar until you find the tip. This will involve digging a narrow, somewhat deep trench — rhizomes like to dwell about 4 to 10 inches underground, depending on shade levels and corresponding soil moisture/depth and density.

Some find using a spade or shovel better for this phase of the work, but be careful not to cut the rhizome with larger digging implements — it’s easy to lose track of the rhizome when you resort to blunt-force digging. I make every effort to avoid cutting or breaking the rhizome until it’s traced back to the plant. It’s also easier to pull up a rhizome when you have a longer length of it you can wrap your hands around.

A crowbar is an excellent, somewhat-neglected digging and scraping tool, ideal for problem areas where detail work is necessary and a shovel is overkill.

Begin pulling the rhizome up, pausing every few inches to wedge the crowbar under it to coax free the threadlike roots anchoring the main rhizome to the dirt. Get as many of those roots as you can and pull them out, and DON’T leave any pieces of rhizome — throw them all in a bucket for greenwaste. If (often when) the rhizome breaks while you’re pulling it up, dig down and start again. Using this method, trace the rhizome back to the mother plant.

It’s usually hard, dirty work.

Once you finally get within 12 inches of the main plant, you will probably have to use large loppers or even the reciprocating saw to terminate the thick outbound rhizome.

This is the perfect opportunity to dig a circular ditch around the mother plant. The ditch should be at least 30 inches deep and about a foot wide. Prepare to find other outbound rhizomes…and repeat the steps above.

Maintain the ditch regularly — rake it out and go in with a shovel and excavate any dirt and debris that has fallen in over the subsequent months. Any leaves and organic matter in the ditch will act as mulch and keep the ground moist — a perfect place for eager rhizomes to hide and roam. Examine the exposed soil adjacent to the bamboo and prune off any emerging rhizomes.

There are people who will use Roundup on the outbound rhizomes rather than do the dirty work of pulling them out. I avoid using it (Remuda, Roundup, or any other manifestation of glyphosate) due to its toxicity — this is subject deserving on an extensive blog post of its own — but if you insist on treating the rhizomes with Roundup, opt for the roll-on gel variety. It eliminates the possibility of overspray and lessens the temptation to just drench the soil around the rhizome.

And remember: since Roundup is a systemic herbicide, do not treat any rogue rhizomes with it unless you’ve first severed them from the mother plant. Doing otherwise risks poisoning the entire clump of bamboo.

If you have a runaway bamboo (or even a well-behaved) grove and need a consultation on control and mitigation, please contact me at paul at dobiemeadows dot com. I’d be happy to come out and recommend some solutions.

————————————————————————————————————-

It must be noted that this method of bamboo mitigation was taught to me by Kenny at Moraga Garden Center, Moraga, CA, whose knowledge, patience, and tutoring continues to be indispensable in my ongoing efforts to become a better gardener.

Leave a Reply

Your email address will not be published. Required fields are marked *