Runners, clumpers, and the low-down on planting this popular plant in your garden

BY MIKE BROWN

Most of us think of bamboo as giant stalks that grow to immense heights and terrorize us with fear that they will take over our lawns and neighborhoods. While this is partly true, there are clumping bamboos that are more sedate and there are those that can send out errant runners across our gardens, under fences, and even across concrete driveways. Never choose a bamboo or any plant simply because it looks beautiful in a magazine or at the nursery in a “self-contained” pot. Unless you know what you are purchasing, you could be unleashing a monster in your garden. Remember this simple phrase: “The right plant in the right place.” By knowing this you can save yourself a headache and costly mistakes. Doing some online research or asking your local nurseryman can provide you with valuable information. You don’t want to end up with that monster bamboo in the corner of your little patio garden.

Bamboos are made up of many genera to which there are hundreds of species, and most will not grow in the Southern California environment—so that narrows down the choices for you. When we think of bamboo we think of the giants, but not all bamboos are skyscrapers. Some grow to no more than two feet in height; for example, there are several species of ground-cover bamboo that will densely cover exposed soil in a relatively short time. One species, commonly called the dwarf white stripe bamboo, does great in sunlight or shade and also looks terrific in large containers. Its beautiful variegated leaf is striking and works well with larger accent bamboo. There are also specimen shrub types that make great additions to gardens and can be planted in containers for the patio such as the Pleioblastus “Tsuboi” that tops out at about five feet in height. The Mexican weeping bamboo will grow to about eight to 12 feet and has very thin leaves making it look very graceful when the wind blows.

Because bamboos have high water requirements, they are not the most eco-friendly of plants, however, it is important in the beginning to give them adequate water to get them established and then you can taper off after several months of established growth. When thinning out a bamboo clump you can use a hand saw to saw out a large clump from the mother plant. Try to get at least three culms or canes in the new clump. If the canes are tall and leafy, cut back the tall cane in half to reduce water loss from the leaves as the root system will now be reduced. Fertilize bamboos in the garden from March through October with a high-nitrogen fertilizer once a month. Bamboos that you have in containers must not be over fertilized and it is best to use a timed-released, balanced fertilizer for feeding.

Now for some name-calling—the Phyllostachys genus includes most tall- and medium-sized hardy bamboos. The bamboo phyllostachys atrovaginata (I am not responsible for giving that bamboo species their names but it may be easier to call by its common name, the “incense bamboo”) has the faint smell of incense when the foliage or canes are scratched or crushed. It is a very fast-growing upright plant that is relatively large in diameter in relation to its height. It can grow to 30-plus feet in height and the culms (new stalks) grow to about 2 1/2 inches diameter.

The phyllostachys aurea grows to 40-plus feet and the culms are 1 1/2 inches in diameter. It is also known as the “golden bamboo” or “fish pole bamboo” and it is one of the strongest bamboos grown. It is great for hedges and next to walkways and driveways. Nodes (the growth lines on the stalk) are often distorted and make interesting ornamental art. Like most phyllostachys, when exposed to strong direct sunlight this species turns golden yellow.

The phyllostachys nigra (black bamboo) can grow up to 40-plus feet in height and 25-30 feet in width with two-inch culms. Under ideal conditions it will grow beyond 40 feet. The new culms are green and turn black within two to three years.

Clumping bamboo has U-shaped rhizomes (root system) instead of horizontal growth rhizomes, and the new culms emerge next to the root ball and never spread farther than a few inches from the mother clump. A great sun-tolerant clumper is the Fargesia robusta which grows to 12-15 feet in height and has culms three-fourths of an inch diameter, does best in zones seven to nine and needs high heat and humidity. This would do better along the coastal canyons where humidity levels remain relatively high throughout most of the year.

If you must plant a running bamboo, be sure to use a high-density polyethylene barrier to control the fast growing rhizomes. It is recommended to use a 40-millimeter polyethylene barrier with a 24-inch minimum width. Dig a trench two inches shallower than the barrier width (so that the barrier extends over the soil) as this will help to keep the roots from growing over it. Don’t waste your time with concrete barriers, these will crack and metal barriers will rust. On steep hillside slopes you will need 30- to 36-inch wide barriers to keep erosion from washing away the topsoil. Prices vary and start at $1.75 per foot.

Remember, what are you trying to achieve in your garden design; screening and privacy or adding textures and color to the existing palate or simply adding a specimen plant to your collection? Whatever your reason, don’t forget to “plant the right plant in the right place”; this is especially true for bamboos. So head out to your local nursery and check out the great choices of bamboos that are available.

Mike Brown is a garden and landscape designer in Los Angeles. Please e-mail him at greengardenguy@yahoo.com with any questions, future topics, or suggestions.