To designers, bamboos offer unique opportunities in the landscape, especially as outdoor space becomes more restricted. Some ideas are to create a wall separating spaces, a privacy screen, aid in the style of an Asian garden, or for utilitarian uses, such as garden stakes and building scaffolding (outside the U.S.).
One might not immediately think of bamboo for small spaces, and Phyllostachys bambusoides, or giant timber bamboo, certainly challenges this notion. With proper installation and maintenance (by removing old canes or undesirable sprouts), bamboo will adapt to its available planting area. Restricting the root zone is key.
Manufacturers have developed solid, modular root barriers installed around the perimeter of planting areas that mitigate their spread. The barriers need to be installed correctly, otherwise bamboo will find its way around to escape. For example, there are some images online that instruct the use of wood borders, which I do not recommend. Over time, the wood will deteriorate, allowing the bamboo to spread. Any joints will also be vulnerable to their escape, which is why professionals will specify a continuous, overlapping modular system devoid of any vulnerable seams.
To be clear, there are essentially two types of bamboos: runners and clumpers. The running types will continue to expand in what can be considered outwardly aggressive movement, whereas clumping types will remain in a tight central area...still expanding outward but at a much slower pace (easier to manage). P. bambusoides falls under the category of a runner, so containing its growth is well advised. This also serves as a reminder to pick the right bamboo for the right space.
I have observed gardeners severely cutting the tops of bamboos (shown here), regardless of species., perhaps as an aesthetic choice, like shaping shrubs into boxes and flying saucers. They look butchered. My hunch is that the designer or homeowner chose the wrong species that reaches heights that were unaccounted for, such as placing large bamboos under house eaves. They may see this as a simple means of control. This is where bamboos and trees share a common design rule: the right plant for the right place to avoid disaster down the road.
There is, however, a fascinating method for controlling madake and other bamboos. To understand the technique, one must understand its anatomy. Briefly, what we understand as a bamboo cane is called a culm, and each culm is made up of segments (internodes) divided by nodes. Within each node there is a diaphragm further distinguishing each segment's interior. As a culm grows, which can be a matter of feet per day, the internodes are wrapped in a protected sheath, often referred to as a culm leaf since some are capable of photosynthesis. Foliage leaves will extend from the culm leaf or sheath, which present lush greenery we associate most with bamboo leaves. Now that readers understand these basic terms, we can return to the idea of controlling size without brutally pruning the culms.
According to the author of Bamboo for Gardens, Ted Jordan Meredith (2001), stunting woody bamboos like our Phyllostachys can be addressed by, "removal of the culm leaf [that] stops growth of the corresponding internode. A dwarfing technique for bamboo in the garden, and, more typically, for bonsai" (p. 45). The results are two-fold: reducing the length of the internodes (shorter) and increasing branch density. I have not observed this technique, but now I am intrigued. Keep in mind, this would not be a best practice for landscapers unless the client is willing to pay for dedicated time. Instead, a better practice is for landscape designers is to choose bamboos for their size appropriateness, as I have repeated in this post.
Bamboos, including our giant timber, naturally produce copious leaves creating a very dense mass. These leaves are actually deciduous and will drop as the culm extends upward. At maturity, the foliage appears evergreen despite the frequency of leaf drop, which is a reminder that leaf cleanup should be considered for maintenance. This density can be desirable, however, for screens, background borders, and a forest like appearance.
Lastly, and this is directed to my students learning plant identification, bamboos are not so easy to identify without further study beyond our coursework. Some bamboos, like this giant timber bamboo, or black, variegated, or striped bamboo are more readily identifiable, and we will focus on those for our studies. Consider any bamboo postings here as introductory to encourage further study and research. Additional bamboo identification information can be found from Dr. Chris Stapleton on his website.
Off Campus Locations: Hakone Gardens, Saratoga, CA.
Foothill College Bamboo Garden, Los Altos Hills, CA
Botanical Name: Phyllostachys bambusoides
Phylostachys: Greek for phyllon, or leaf, and stachys for ear of grain, meaning that leaves will appear on the flowering shoots.
Common Name: Giant timber bamboo; Japanese timber bamboo; madake
Family Name: Poaceae
Garden Themes: Asian-inspired, tropical, pool (do not forget root barriers)
Uses: Timber, tall screen, grove, edible shoots, mass, barrier
Type: Evergreen bamboo
Form: Erect, runner
Size: 70' and spreading (often smaller away from native environment, including within the United States)
Outstanding Feature(s): Form
Canes: Up to 6" in diameter, bright green (often only 3" in the United States)
Margin: Entire, pubescent
Color: Light green
Surface: Glabrous above, pubescent underside
Flower: Infrequent, possibly on 120-year cycles (Meredith, p. 51), hence bamboos rely primarily upon their spread by rhizomes. To really understand their flowering, it is best that I simply quote Dr. Stapleton: Synflorescence prominentlybracteate, partially iterauctant, composed of 1–7-spikelet racemes gathered into fascicles or globose mass subtended by a tiny, membranous, 2-keeled prophyll, 0–1 gemmiferous bracts, 2–6 gradually enlarged scaly bracts and 2–7 spathiform bracts. Spikelets sessile with 2–7 florets, the terminal one sterile. Glumes 0–1(–3), Rachilla extending beyond uppermost floret, disarticulating just below fertile florets; lemmas varied in size and texture; palea 2-keeled, not exceeding the lemma, apex bifid. Lodicules 3, ciliate. Anthers 3, filaments free. Stigmas (1-)3.
Fruit: Just as infrequent, is a small caryopsis.
cultural requirements, tolerances & problems
Sunset Zones: Only states -5° F (-21° C)
USDA Zones: 7-10
Light: Sun to partial shade
WUCOLS SF Bay Area Hydro Zone: Low
Texture: Sand, loam, clay
Moisture Retention: Limit periods of dryness (dry soils will somewhat limit outward expansion)
pH: Lightly acidic to lightly alkaline
Problems: May become invasive if not confined by barrier
Cane Strength: Strong
Insects: Scale, mealybug, aphid, mite
Disease: Sooty mold (if insect infestation persists)
citations & attributions
Bayton, R. (2019). The Royal Horticultural Society's the Gardener's Botanical: An Encyclopedia of Latin Plant Names. London: Mitchell Beazley.
Extension Gardener. "Lantana montevidensis." North Carolina State University, Raleigh. Accessed on October 20, 2021, from https://plants.ces.ncsu.edu/plants/lantana-montevidensis/.
Meredith, T.J. (2001). Bamboo for Gardens. Portland: Timber Press, Inc.
Norris Brenzel, K. (Ed.). (2012). The New Sunset Western Garden Book. New York: Time Home Entertainment, Inc.
Water Use Classification of Landscape Species. "WUCOLS IV Plant List." University of California, Division of Agriculture and Natural Resources, Davis. Accessed on February 11, 2022, from https://ucanr.edu/sites/WUCOLS/Download_WUCOLS_IV_List/.
Bamboo barrier detail: "Installing WB 36/30 for Bamboo Control at Toledo Zoo: Toledo, Ohio" by Deeproot is licensed under Creative Commons NonCommercial-NoDerivs 2.0 Generic (CC BY-NC-ND 2.0).
All additional photos by TELCS.