Good Things Growing
The latest edition of the Garden Dirt is in your mailbox and available at The Gardens now! Below is Executive Director Fred Spicer’s “Good Things Growing” column for the January/February 2012 edition.
Few plants evoke an Asian aesthetic like bamboo. However, running (monopodial) species can be very aggressive spreaders. Understandably, many people consider them invasive exotic plants, although river cane, Arundinaria gigantea, and its relatives are important plants in their SE US native ecosystem.
Clumping, or sympodial, bamboo species offer a guarantee of self-restraint. Despite the ability of their basal clump to reach 5-6′ wide and more over time, have no fear, the plants are genetically incapable of running. However, they have not been widely used in our area, perhaps because some clumpers exhibit borderline cold or heat tolerance, or because runners are easier to propagate. Maybe it’s disbelief – those who have experienced the tenacity of the monopodial species mistakenly think that all bamboos ate noxious pests.
We grow several types of sympodial bamboo at The Gardens, primarily cultivars of Bambusa multiplex, hedge bamboo, from China. As the name suggests, its growth habit lends to clipping as a hedge. Over the past 8 years, our earliest plant-outs of “Rivieriorum,” considered the hardiest form, have formed well-behaved, dense, graceful, finely-textured and fountain-like evergreen clumps ~ 10′ tall and wide (left); the basal clumps of emergent shoots are ~ 36″ wide. They have withstood heat, humidity and drought with total aplumb, as well as a brief flirtation with single-digit lows with minimal aboveground injury.
On hedge bamboo, new culms (individual grass stalks) arise through the growing season, primarily late spring-early summer. Height increases gradually (up to 18′ in our area) as the clump matures; growth is slowed compared to monopodial species. Leaves (secondary growth) are produced after maximum culm height is reached each year but late-season culms may not produce secondary growth until the following year. After leaves are produced individual culms cease all growth, and live 3-7 years. Clumps can be attractively thinned by removing individual culms, or completely renewed to the ground in late winter before new growth ensues.
“Alphonse Karr” sports attractive gold culms streaked with green. Leaves are larger than “Rivieriorum” but suffer complete injury at ~15 degrees F (above), necessitating renewal pruning. “Fernleaf,” as supplied to us, appears very similar to “Rivieriorum,” perhaps with slightly less stem hardiness. We’re also growing Borinda boleana and Fargesia spp.; time will tell if these clumping species also have potential.