Let your bamboo garden grow
Some people are a bit intimidated by bamboo because although it is extremely easy to maintain it is perceived as hard to control because it spreads rapidly. The spreading is easily remedied and the benefits of bamboo greatly outweigh the pitfalls. “Today” gardening expert Rebecca Cole has advice on how to get started.
There are many ways to use bamboo in your garden design. It can be used as a wall or screen to provide privacy from your neighbors, in containers for your deck, terrace or patio or as means of creating your own secret bamboo forest to wander through.
It mixes well with both perennials and annuals and can be used as a tall or medium background plant, an accent plant or as a low border or ground cover plant depending upon the variety you choose.
Bamboo is a Grass colony plant. There are over 1200 types of bamboo worldwide and about 200 species that can be grown well in North America.
An interesting fact about bamboo is that the main stems (referred to as culms or canes) emerge from the ground in the diameter that they will always be. And, the next season’s new culms usually emerge wider in diameter and grow to be taller than the older canes. Therefore, the youngest canes in your planting are the thickest and tallest.
Here’s what to consider when choosing a bamboo:
There are two types bamboo root systems, (referred to as rhizomes) which will greatly affect your choice of bamboo. The first is found in more temperate environments and is known as runners. These spread like crazy and will end up everywhere if not taken care of properly. The second type is known as clumpers. They are normally found in more tropical varieties. Although this variety spreads as well if not pruned, it is generally not as invasive as the runner types.
Bamboo comes in a variety of heights and can be trimmed from the top if it gets too tall. Generally speaking the larger bamboos like yellow groove prefer several hours a day of direct sunlight, while the smaller bamboos (under 20 feet tall), can tolerate partly shady conditions.
In the spring, the leaves yellow and then drop. The loss is gradual, as they are replaced by new ones. A healthy bamboo should have a mixture of green leaves, yellow leaves and newly unfurling leaves. If leaves are dropping and there are no signs of new ones, then the bamboo is probably standing in water. If the leaves are crisp, the bamboo is probably bone dry. They are two totally different looks with opposite remedies and easily discernible.
How to plant bamboo
Bamboos prefer a neutral soil- regular potting soil is fine- and they can be planted at any time of the year in mild climates. In colder climates they should be planted early enough to harden off to survive their first winter. A heavy mulch of any good compost should be used to protect the bamboo. When choosing mulch, you want to look for one with good insulation value and one that will retain moisture. If the roots freeze when they are moist, (opposed to freezing dry) the plant has a better chance of surviving. Four to five inches of mulch on top of the soil should be sufficient.
When using bamboo as a screen or hedge you want to treat the whole area by laying down good compost or manure, so when it spreads it travels into good soil. When planting very tall and slender bamboos, they may need to be staked to prevent wind from uprooting them or damaging newly formed roots. Generally, smaller bamboo do not need to be staked because the rootball is big enough to support the plant. Generally speaking, after five years under good growing conditions, a single planting will yield 30 to 40 culms, 3/4 inches in diameter and 20 feet high (dependent upon which variety you choose.)
Spreading is the usually the biggest concern for those who would like to incorporate bamboo into their gardens.
Typically there are three ways to control spreading.
The first is by creating a natural barrier for the bamboo. Planting at the base of an uphill or near standing water will control the spread without too much Rhizome pruning because the bamboo will not spread uphill.
If the first is not an option, you can buy root barrier. This is available at larger nurseries, comes in plastic rolls and can be used to line a trench dug around the bamboo about 20” from the main root system. When the spreading roots meet the barrier they will be forced to the surface where they can be easily pruned. It is possible that the roots can jump the barrier so it is best to leave about 2” of the barrier above the surface. The best time to prune the unwanted sprouts is in October when they are softest. However, if needed, they can be pruned in the spring as well.
A third method for Rhizome pruning is an organic method. Dig a trench around the bamboo about 10” wide and 12” deep and fill with a loose, organic peat moss or mulch. Like with the other methods, some pruning is unavoidable and necessary to keep the bamboo from spreading to unwanted areas of your garden. In the fall, you should remove the mulch and prune any unwanted rhizomes.
As far as watering goes, you should water your recently planted bamboo frequently, but not longer than a few minutes each day because bamboo does not like to sit in water. Once it is full-grown it can survive on less water.
Because bamboo is a grass you can feed it with the same fertilizer you would use to feed your lawn and should be done approximately twice a year.
Leaves rolled up: Dehydrated
Needs water or is in too much sun.
Culms go soft and start to rot: Undernourished
If the culms go soft and rot at the end of the growing period, their nutrition has been disturbed. Remove all rotten culms and most of the older culms. Typically, canes survive 6-10 years. When they die, you can cut them out, tight at the base. The root system can survive longer. An indication of a healthy root system is new sprouts each spring!
Problems with bamboos grown in containers: Too dry or too wet
Make sure the soil has not been compacted through the use of hard water. If that’s the case then repotting is necessary. Do not let the roots dry out because the plant will not be able to take up any more water and the foliage will drop off.
Rebecca Cole is the gardening editor for the “Today” show. She is also the author of “Paradise Found: Gardening in Unlikely Places.” For gardening tips and information, you can visit her Web site at: www.colecreates.com.