Control of Bamboo
Techniques for Running Bamboo:
Bamboo does not have to be a nuisance, and typically is not. Managing your running bamboo is made easier when you adopt a routine and schedule of practice. In doing so, you can enjoy your bamboo and utilize all of its attributes around your home and community.
Each fall, in late September or October, prune around the perimeter of the bamboo. Use a flat-bladed spade or shovel to a depth of about 8 to 10 inches to cut the rhizomes (which spread in search of water and nutrients). Pruning or mowing rhizomes earlier, in late spring or summer, can help to confine the bamboo to smaller perimeters. After cutting the rhizomes, simply pull and remove them.
You can dig a narrow trench, about 3 inches wide and 10 inches deep, around the bamboo to easily monitor the perimeter. Thereafter, any rhizomes that cross the trench can be easily spotted and cut. You can use a bamboo pole to drag along the trench and feel for rhizomes. Simple!
Using Rhizome barrier:
Another method is to buy and install polypropylene rhizome barrier. At about $3.00 per linear foot, barrier adds cost but eliminates the need for routine rhizome cutting. Rather, you are essentially creating an in-ground, open-bottom container in which your bamboo will grow. The rhizomes will grow horizontally, and to a depth of about 26-28 inches (not very deep -- barrier is typically available at 30 inch widths), so that when you install, you can keep a few inches above ground, creating a rim. Install the barrier on an angle (creating a bowl shape) so that when the rhizomes bump into the barrier, that are encourage to grow up towards the rim, and then simply trim.
Close the length of barrier (to form a closed circle) by overlapping the ends by 12 inches, and securing fastening using strong glue and/or stainless steel fasteners. You want a tight, gap-free enclosure to prevent any rhizome escape. Fill your barrier bed with compost and soil, and enjoy.
After a few years, you will want to thin your bamboo, as you would any plant that becomes root-bound in a pot. You can do so by cutting chunks of rhizome from the bed and replacing with fresh compost and soil. The chunks (with canes) make great gifts for others to enjoy.
Raised Beds and Pots:
Bamboo can grow well in raised bed boxes providing that they are well watered (happy not soggy) and well fed (compost, etc.). A bed of 2 feet by 2 feet made of treated lumber can easily be assembled and disassembled to facilitate easy management. The open bottom should be monitored since, lacking a barrier, the rhizomes may be encouraged to grow under the frame. Keep the bed properly thinned (annually) and the rhizomes should grow horizontally and up rather than down and out.
Large plastic pots with drainage holes can also be used. Place the pots on stone pads to prevent rhizome contact with soil. Pots can be 18 inches deep and 24 inches in diameter. They can get heavy when wet, so think about placement to minimize relocation. Like the raised beds, you will want to thin these potted bamboos.
Techniques for Clumping Bamboo:
These bamboos do not run and grow in close proximity to the “mother” clump. They can be pruned and managed similarly to that of running bamboos. Hence, barrier material is not necessary.
For the first year of planting, do not prune any culms (canes) so that the plant can receive as much food and energy (via photosynthesis) as possible. During the second and third year, selectively prune to remove short and weak growth, and to create spacing of about six inches between culms. Doing so will allow space for new shoots in the spring. Too many shoots or shoots that are too thin to save? Cut and eat them! Get them early before they toughen.
Shrub size and Dwarf bamboo:
These bamboos can be pruned dramatically to encourage vigorous, bushy growth each year. Enjoy the resulting ground cover and lush looking foliage.
Now, without worry, enjoy your bamboo!