Care & Feeding of Bamboo
The “culm” is the above ground bamboo stem, often called the "cane". It has nodes and is usually hollow between the nodes, though some species of bamboo have solid-core canes. The node is located where branches, buds or roots are found. It has a membrane spanning the inside walls, creating a chamber for each node. Pop the chambers and you have a natural tube or pipe.
The emergence and growth of a new cane occurs with “shooting”. Canes grow to climax height in approximately 3 months time, the height it reaches for the life of the cane. Once grown to climax, it will live for between 5-10 year, contributing photosynthesis energy back to the clump. As a plant, not a tree, bamboo has no cambium ring and so does not grow outward like trees. Rather, it grows upward, emerging widely from its base and gradually tapering towards its tip.
Mature grove height and cane diameter (i.e. when most culms of the clump are produced at optimal dimensions) may take 6 to 10 years for the midsize timber bamboo. Dwarf and shrub size bamboo may take 3 to 6 years. Maximum size is dependent on environmental conditions like access to water and nutrients, and best-practice management techniques (i.e. selective harvesting, optimal feeding, etc.).
In the US, within the temperate climate of the Pacific Northwest like elsewhere in the world, bamboo can thrive and be planted throughout the year. It can acclimate readily, except during severe freezing temperatures. Protection of young, vulnerable bamboos should be provided against strong, cold winds and temperatures.
Bamboo is tolerant of most soils, but they prefer a loamy, slightly acidic soil with a pH between 5.5 and 6.5. If you have a heavy and/or clay soil, mix in compost until the soil easily crumbles in your hand. For sandy soil, use compost to retain moisture and offer nutrients. Adding biochar can also help build soil and sequester nutrients for longer-term feeding and care.
Rhizomes are the woody, cane-like roots of bamboo, with hairy, mini-roots which act to absorb water and nutrients. The amount of rhizome spread depends upon the species, time in the ground, actual growing conditions, and access to sun, soil and water.
Running bamboos: like the Vivax stand (in Washington State) pictured at right, leptomorph produce rhizomes that grow laterally through the upper surface of the soil and sometimes right above the surface. In the Pacific Northwest these primarily grow from early summer until mid fall. New canes shoot up in the spring to early summer from bud spaced along the rhizome.
Clumping bamboo's: like the clump of Bambusa pictured at left, pachymorph slowly grow wider each year and do not run. Some have rhizomes that are more elongated than others. Canes on cold hardy clumpers often should in late spring to Midsummer and again in the fall. They grow off the tip end of the rhizome.
For newly planted bamboo, keep the soil moist (not soggy) for the first two weeks. Too much water will cause excess leave drop. During the shorter daylight and rainy seasons, bamboo will use less water. When watering, and when the soil is very dry, occasionally check to verify that water is reaching the bottom of the rootball as very dry soil can repel rather than easily absorb water.
For the first and second year, water deeply at least once or twice a week during warm dry or light rain or cold dry weather. Make sure the water is soaking into the roots, not just running off. Soaker hoses or drip irrigation grow healthier plants with less water.
Occasional deep watering during summer or fall dry spells should be sufficient in the Pacific Northwest if you noticed leaves curling up it is a sign of stress. Dryness is often the cause.
Pest Management Tips
Bamboos grown in the US and elsewhere in the world have relatively few pests. Spider mites and aphids often affect the appearance of the leaves, but do not compromise the health of the plant. Slugs and snails and large herbivores may do significant harm. Simply remove leaf litter when observing infestations and avoid use of pesticides as they may kill useful predator insects.
Aphids are translucent, soft-bodied insects often shown up in early summer. They will leave a sticky residue on the leaves which later turned to a city black film. This will remain until the leaves are shed the following year.
You can reduce the aphid problem by pruning your bamboo to allow good air circulation. Also, occasionally spray the leaves with a strong jet of water and wait for predators like birds and ladybugs to do their work. Often horticultural oil or insecticide soaps used for mites will also be helpful in the control of aphids.
Signs of bites, gnawing, and chewing on new canes could indicate presence of slugs or snails. Herbivores such as goats, cows and horses enjoy eating bamboo canes and may require fencing. Deer are generally not problematic.
Applying 2 to 3 inches of course mulch, like bark chips, leaves, or grass clippings, can help to conserve water and prevent weeds, and insulating rhizomes from severe freezing temperatures. Allowing bamboo leaves that have fallen to remain on the ground provide a helpful ground cover and offer silica back to the bamboo.
Enjoy your bamboo!