Continued: Site Selection for Planting Bamboo

Thanks to Susanne Lucas, of the American Bamboo Society, for permission to print this article – it is written with the American climate in mind but is equally relevant to UK sites.

... Bamboo responds well to supplemental watering, so the incorporation of organic material (i.e. humus) to all soil types to assist with moisture retention and drainage is very beneficial. Composted manures, slow release or organic fertilizers can be added to the backfill material, since bamboos are heavy feeders. There’s an old Yankee expression, “put a $5 plant in a $25 hole”, which applies here. Don’t short cut the soil preparation – it is vital to the survival of the plant. That said, remember, too, bamboo is very tolerant of – and very adaptable to – soil types, pH, and growing conditions.
Plant the bamboo as soon after purchase (or transplanting) as possible. Nothing is more depressing for a healthy plant than sitting around in an unforgiving, heat-absorbing, plastic container, when the option of fresh air, free-draining organic soil, and growing space is available. Salts accumulate in many potting soils, too, and temperatures fluctuate within plastic, so be kind and plant your bamboo as soon as possible if the weather is suitable. Plant during a cool rainy season, if possible, or just before this can be predicted. As a general rule of thumb, bamboos planted just before their active shooting period transplant more enthusiastically than those planted during the fragile shooting stage (leading to shoot abortion and easily subjected to mechanical injury). Once new shoots have hardened off and culms have branched and leafed, plants are easier to handle and transplant.
The depth at which to plant the new plant is not as critical as it is with other plants. Deeper planting can help stimulate dormant buds on basal nodes and also anchor the plant from rocking significantly from winds. Clumping bamboos exhibit “tillering”, common in many other grasses, this actually is encouraged by deeper planting.
However, if soils do not drain quickly, new plants should be set higher, on a mound.
Alternately, if soils are fast draining, set plants in a shallow depression and create a “saucer” around the top of the hole to hold water near the root zone.
After the new plant has been back-filled, soak the plant several times and top-dress with an organic mulch to conserve water and keep the soil temperature consistent. The frequency and amount of watering after planting will depend on site conditions, i.e. soil texture, sun exposure, wind exposure, competition from nearby roots, air temperature, etc. Some bamboos will quickly roll their leaves, indicating drought stress, but this can also be a reaction to strong sun. Best advice is to investigate the actual soil moisture content and water accordingly.
Acclimatizing (Adjustment to a new location)
Acclimatizing, or acclimating, newly planted bamboos can be very important in harsh environmental situations, primarily protection from winds and strong sun. This is especially true when transplanting bamboo freshly divided from mature groves. Applying mist to the leaves will help reduce transpiration, as does the application of commercial products called anti-dessicants (Wilt-Pruf). Try to do transplanting and planting on cooler, cloudier days, if possible, preferably before rains. Otherwise, do everything possible to keep high humidity around the plants. Provide cover and shade during transport and throughout the planting process. Don’t allow waiting plants to sit in the sun, or subjected to winds or excessive drying out.
Irrigation
Irrigation is another word for watering, and whether it is a single plant getting a hose brought to it regularly or an entire grove with drip tubes, irrigation can be a simple or complex system. Bamboos respond to water, no question. This is especially important upon establishment of new plants. Adequate water will ensure survival, and more water will bring larger, faster development. Again, site conditions prevail. Regular watering throughout the growing season, especially during new shoot season, brings the best results. Most temperate bamboos appreciate a minimum of an inch of water per week, during active growing months.
Staking
Newly planted bamboos sometimes require staking, particularly if they are of the taller growing types, like Phyllostachys or Semiarundinaria. Since these plants have not established a cohesive network of rhizomes to support their height, wind can wreck havoc and topple over the new specimen. Use three or more posts and connect with strong rope between the culms, breast-high, with some “give” to allow gentle swaying. Take care to protect the surface of the culms with some soft cloth or burlap, so scarring does not occur. Using bamboo canes as staking helps some in camouflaging the artifice, and aesthetic considerations can add interest to the staking rather than detract from the clump. Tight control of the culms can lead to breakage, so be careful not to secure the plant too tightly. This is especially true in areas that experience snowy winters.
After the first year, any staking can be removed, as the rhizomes have taken hold and a healthy root system should be enough to hold the plant up. Part of the process of establishment in the first year is growth that is somewhat “limp”. Typically, larger stature bamboos like Phyllostachys take at least 3 or more years to attain some maturity (in cold areas, it may take 10 years to reach maturity). The first year, new shoots may emerge as wispy, grass-like branches, not the desired strong-as-steel vertical culms. There is no sense in trying to stake these culms, rather tolerate them with appreciation, as they are collecting and storing food for the future culms, and should not be removed until future year’s growth supplement the planting. Once the root system has developed extensively, stored lots of carbohydrates, can the planting produce impressive size culms. Be patient. As fast as the fastest-growing plant in the world can grow, sometimes this takes time.
Fertilization
Bamboos are grasses, and grasses thrive on good nutrition. They are also adaptable, and can be neglected and still survive. However, if you want your bamboo to thrive and flourish, annual applications of slow-release fertilizers, composted manures, or any organic topdressing will bring happy bamboos.
Mulches protect bamboo roots from extremes in temperature and soil moisture, and the breakdown of organic mulches benefit the soil structure and provide important nutrients.
The natural annual shedding of the bamboo leaf canopy provides the perfect mulch. Do not remove these leaves; they provide all the necessary nutrients the bamboo needs.
Once established, bamboos are incredibly resilient and drought resistant. They are survivors. They tolerate neglect, abuse, and extremes. If all the vital characteristics were explored upon selection, such as cold/heat/sun tolerance, and if initial watering requirements were met, bamboo is a very long-lived plant and will be a part of the landscape for many decades.
For more information about bamboo, go to www.americanbamboo.org