Growing and Maintaining Bamboo

Placement and Spacing

Although most people have a place in mind as to where they want to plant their bamboo, one should keep in mind that most large bamboos (Phyllostachys) do best with 5 or more hours of direct sunlight. They must be given ample water, fertilizer, and protection from competitive weeds. They will benefit from a windscreen and light shade when first planted as well. This is especially true of smaller plants. Fargesias, Thamnocalamus and Sasas do well with light to moderate shade. In fact the Fargesias and most Thamnocalamus are happier with some shade during the hottest part of the day. Fargesia and Thamnocalamus are the hardiest of the clump type bamboos. They can be planted without fear of spreading. Most other hardy bamboos can spread by their underground rhizomes and this must be taken into account when planting them. We recommend annual root pruning as the first option for control. Also, barrier of 60 mil by 30 inch deep, HDPE (high density polyethylene) can be used for rhizome control. See this page for control methods

Bamboo should be spaced 3 to 5 feet apart to form a dense screen. The faster spreading types can be planted farther apart, if you are willing to wait a little longer for the screen to fill out. Starting from a small size, most bamboos will reach mature height within five or six years. As a very general rule, Clumping bamboo gain about 1-2 feet of height per year, and the Running types grow about 3-5 feet per year, and spread outward at the same rate. Height and spread rate is variable depending on the species and climate. If as instantaneous screen is desired, most bamboo will not suffer from being planted nearly back to back. Feel free to contact us to discuss details about your project.

Planting Your New Bamboos

Most bamboos are happiest in a moderately acidic loamy soil. If your soil is very heavy you can add organic material. It can be dug into the soil where the bamboo is to be planted, but the easiest thing is to mulch very heavily and let the earthworms do the work. Spread two or more inches of mulch in the area around the bamboo, and where you want the bamboo to grow. Bamboo is a forest plant and does best if a mulch is kept over the roots and rhizomes. It is best not to rake or sweep up the bamboo leaves from under the plant, as they keep the soil soft, and moist, and recycle silica and other natural chemicals necessary to the bamboo. A low-growing shade-tolerant groundcover plant that will allow the leaves to fall through to form a mulch without being visible will work if you find the dry leaf mulch objectionable. Almost any organic material is a good mulch. Grass is one of the best, as it is high in nitrogen and silica. Home made or commercial compost is great. Hay is a good mulch too but hay and manure are often a source of weed seeds, so that can be a problem. Any kind of manure is good, if it isn't too hot. Limited amounts of very hot manures like chicken are OK if used with care. At our nursery we use a large amount of chipped trees from tree pruning services. This can harbor pathogens that can affect some trees or shrubs, but the bamboo loves it.

Timing and winter protection

Bamboos can be planted at any time of the year in areas with mild climates such as we have in the maritime Pacific Northwest. In colder parts of the world they should be planted outdoors early enough to become established and to harden off sufficiently to survive their first winter. If the bamboo is planted late in the year, one should mulch the plant heavily and provide extra protection from any cold and drying winds. In colder climates where bamboos may be marginal, successful growers usually protect their bamboos through the winter with a heavy mulch. Even in very cold climates in an established bamboo grove with a heavy layer of bamboo leaves covering the ground, the soil will be soft and friable during periods when the surrounding soils are frozen hard and deep.

Controlling the spread of bamboo

We recommend annual root pruning as the first option for control. Also, barrier of 60 mil by 30 inch deep, HDPE (high density polyethylene) can be used for rhizome control. See this page for control methods . If you plan to install a barrier to control the spread of running bamboos, it is important to install it properly to ensure its effectiveness. In other than very light soils, the bamboo rhizomes are usually in the top few inches of soil. However when the rhizome encounters an obstruction it will turn, and sometimes it will go down. It is important to avoid loose soil or air pockets next to the barrier or the bamboo may go deeper than you want and perhaps go under the barrier. When filling the hole after placing the barrier, tightly compact the soil next to the barrier. Any soil amendments must be added only in the top foot or so. You mustn't encourage deep rhizome growth if you want to contain the bamboo. If the bamboo planting can be surrounded by a shallow trench 8 to 10 inches deep, this can be a cheaper and easier method to control its spread. See link for pruning trench technique. You just need to check a couple of times in the late summer and fall to see if any rhizomes have tried to cross the trench, and cut them off. Checking for spreading rhizomes is very important. It must be done each fall, whether you are using barrier or a trench.

Growing bamboo in containers
Bamboo may be grown in a pot if there is not a suitable place to put it in the ground, but more care is required. Watering is more critical as bamboo does not like to dry out, nor does it like to be soggy. In containers bamboos, especially those that are not well adapted to hot sun, require more care in placement as they can be damaged if the pot overheats. During winter, container bamboos are susceptible to freezing and if not protected may die. Bamboo in containers is not nearly as hardy as the same bamboo would be in the ground. Bamboo can be a fine container plant if its needs are met.

Staking tall plants

When planting very tall and slender bamboos, they may need to be staked; actually guyed is a better term. This will prevent wind from uprooting them or damaging newly formed roots. Tall bamboo plants are best guyed with a rope tied to the culms up about ½ way up, and to short stakes on 3 or 4 sides of the plant at sufficient distance to give the strength needed to prevent the wind from uprooting the stakes.

Yellowing and falling leaves.

In the spring there is considerable yellowing of the leaves, followed by leaf drop. This is natural and should not cause concern, as bamboos are evergreen and naturally renew their leaves in the spring. They should loose their leaves gradually as they are replaced by fresh new ones. In the spring on a healthy bamboo there should be a mixture of green leaves, yellow leaves and newly unfurling leaves.

Water

Newly planted bamboos need frequent and liberal watering. Twice a week during mild weather, and perhaps even daily during hot or windy weather, give your bamboo a good watering. Make sure that each plant under 5 gallon pot size gets at least ½ gallon of water. For plants over 5 gallon size more than 1 gallon is advised. Once a bamboo has reached the desired size, it can survive with much less irrigation. But until then you must water and fertilize copiously to achieve optimum growth. Lack of sufficient water especially during hot or windy weather is the leading cause of failure or poor growth of new bamboo plants. Watering newly planted bamboos every day, or for longer than a few minutes can cause excess leaf drop. Well-established bamboos are rather tolerant of flooding, but newly planted bamboos can suffer from too much as well as too little water.

Fertilizing
Bamboo if planted in a suitable site (full sun for most, partial shade for some) and given ample water can grow and eventually thrive. But if you want a healthy attractive vigorous plant, you must fertilize. We use a lawn fertilizer it is high in nitrogen. 21-5-6 is the formula. Organic fertilizer high in nitrogen is even better, though it is more expensive. Provide a 2-3 inch layer of compost or aged manure around the base of the plant, and outward where you want it to spread, for a natural source of plant food.

Pruning Bamboo
Maintenance pruning
Bamboo like other plants requires some pruning to maintain its attractiveness. Bamboo culms live only to about 15 years. Once each year you should remove older unattractive culms and cut off any dead or unattractive branches. You can prune bamboo without fear of damaging it. Just trim so it looks attractive. Make cuts just above a node, so as not to leave a stub that will die back and look unsightly. If you cut back the top, you may want to also shorten some of the side branches so the plant will look more balanced, not leaving long branches at the top.

Thinning for large culms
Timber bamboo will grow large more quickly if you remove the smaller and older culms so newer larger ones will have room to grow.

Topiary
Bamboo may be trimmed in topiary fashion. You may top the culms, remove some lower branches, and shorten some side branches and remove others. Any culms or branches cut do not grow back longer but only grow more leaves.

For Screens or Hedges
Bamboo may also be cut to form a hedge as one might do with boxwood or other traditional hedge plants if one wishes. This is best done after the new culms grow to full height in the spring or summer. (Most of the new growth on a bamboo plant happens at the same time of the year, usually late spring or early summer for temperate bamboos.) There should need be only one major pruning, with only minor touch up at other times of the year. If you want to control the size or height of your bamboo, and retain the natural look of the bamboo, this can be done by removing new shoots that are significantly larger in diameter than the culms that are the desired height. These shoots will be replaced by smaller diameter culms that will not grow so tall. This can be safely done with a plant that has been well established, not a newly planted bamboo.

Legging up
For display of colorful bamboos such as Phyllostachys nigra, Phyllostachys bambusoides ‘Castillonis’ and Phyllostachys vivax ‘Aureocaulis’ you can enhance the beauty by removing smaller culms and cutting off lower branches so that the beauty of the culms is visible.

Groundcover Bamboos
For dwarf bamboo we recommend cutting it to the ground each spring, so that the plant is rejuvenated. It will look much nicer when the new growth emerges, and it will be kept shorter and more dense. Dwarf bamboos are also often trimmed later in the season to keep them shorter and more uniform in height. In very cold climates such as zones 4 or 5 dwarf bamboos may have their tops freeze back in the winter and still be good for landscaping. Just mow them as you should do in places where they don’t freeze back.