Much More Than Just a Grass

There are certain plants, which when mentioned in conversation result in a predictable, yet negative response.  For the instigator, it is great fun to see people wrinkle their nose or shift about uncomfortably from one foot to another.  A plant that I can certainly count upon to generate this response is a group of grasses collectively called Bamboo.  It is odd how our perception of them is often so negative, yet their ornamental, economic and environmental benefits are often so positive.  Over the next year, I will discuss several different genera and their associated, yet overlooked benefits.

Believe it or not, Bamboos are actually a grass, and are in the Bambusoideae, a subfamily of the Poaceae (grass) family.  Genera hardy to NJ range in height from 12” to 30’, and can either be deciduous or fully evergreen.   The stem of a bamboo is called a culm, which is divided into a series of nodes and internodes.  The typically swollen and solid portion of the culm is the node, while the internode is the interstitial portion between the nodes.  For the genus Phyllostachys, the internodes are marked by a groove or sulcus that alternates from side-to-side along the length of the culm.  The sulcus is caused by the presence of a branch bud at the base of the internode.

At the Rutgers Gardens, one of the more interesting destinations for a visitor is the groove of Phyllostachys nuda.  The repetition of vertical lines from all the culms creates a captivating affect, difficult to create with other types of plants.   A spreader, the groove originated as three small clumps in 1955 and now covers over ½ acre!  Fully evergreen, Phyllostachys nuda is probably the hardiest of the taller growing bamboos.  In late April, the new shoots begin to emerge from the ground.  A protective leaf called a sheath covers the shoots.  This sheath is dark mahogany in color, with stunning light brown swirls ‘painted’ through the sheath.  These leaves gradually fall as the shoot elongates.  As the culms near 2’ in length, the rate of growth rapidly increases from 1-2” per day to nearly 3’ per day!!  You could literally watch the plant grow.  As the shoots approach the mature height, branches and leaves develop, and the rate of growth once again decreases.  The culms reach their mature height in 30 days.

Another interesting species at the Gardens is Phyllostachys aureosulcata var. spectabilis.  Phyllostachys aureosulcata is a species often available at Garden Centers; the culms are green and the sulcus is light yellow.  The variety spectabilis has golden yellow culms and the sulcus is green, giving the culms a distinctive variegated appearance.  The bright yellow stems also enliven the darker depths of the clump.  The culms of this plant also create a very ornamental zigzag pattern near the ground.  To date, the foliage of this selection has remained exceptionally attractive and glossy, with the stems providing excellent winter color.

Do not rule out Phyllostachys for the smaller garden simply because this genus likes to spread; they can be contained.  However, the prescribed area that the plant is permitted to grow must match the height and stature of the plant.  A bamboo that is 20’ tall will rapidly become root bound and loose vigor within a 3’ diameter containment.  An area that is 20’ in diameter is far more suitable.  One of the easiest physical barriers to install is a heavy gauge plastic sheet.  These sheet measures 30” in height; 28” is buried below grade with 2” protruding.  At the point of overlap, bolting 2 metal strips on either side of the sheet physically seals the sheets and prevents root escapement.  The key is to watch the top of the barrier for any roots that try to jump to freedom!

With proper planning and selection, Phyllostachys are great plants for form and color.  Remember, they are to be much revered, not feared!

 

Last Modified: 12/6/2007, rugardens@njaes.rutgers.edu.
©2008 Rutgers, The State University of New Jersey