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.
Bamboos are very tolerant of soil types and growing conditions, and
in fact, can be planted almost anywhere. The major exceptions include
regions where winter
temperatures dip below minus twenty degrees F (Zone 4 or colder), dry desert
conditions without available irrigation and wet areas (those soils always
water-logged).
With so many types of bamboo (over 1,400 have names, from regions as diverse
as high mountains of Chile, floodplains of North America, tropical rain-forests,
subcontinent India, and mountain forests) and native to all continents except
Antarctica, it is no wonder that one can find a bamboo adaptable to most
any climatic zone.
Planting
So, once the appropriate species has been selected, one must prepare the
site for planting.
Soil preparation includes loosening the soil, adding any necessary amendments,
and placing the plant in the hole. This should be rather simple but is often
the most overlooked aspect of the process. If the soil does not drain well,
or is heavy due to clay or compaction, add coarse sand or other drainage/aerating
amendments.
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