PLANTING and SPACING

The main requirement in planting is to make sure that there are no air pockets around the rootball (this means that when back-filling, the soil should be well tamped and gently compacted around the plant). We like to plant the bamboo an inch or two below the existing grade, or to make a small moat or dish around the plant to facilitate the initial feeding and watering.

If you have clayey or highly compacted soil, your goal will be to loosen and aerate the soil. On a small scale, and for an initial fix, this means a shovel &/or a spading fork. On a large scale this means either digging holes with a backhoe (and amending the mix within) or ripping with a tractor. For long term solutions to clayey and highly compacted soils, good organic compost and mulch (applied once or twice a year) are very good allies.

Bamboos can be spaced according to your goals. Plant closer together for a wall or windbreak, farther apart for a screen; or create an open grid if you are managing your plants in order to harvest lumber or edible shoots. Your spacing will vary by species.

The closest spacing we ever recommend is to place the holes 4 feet "on center" (that means that the centers of the holes are 4 feet apart from each other); for a species like Malay Dwarf (B. glaucophylla) this would result in a dense wall of bamboo. For species like Dendrocalamus membranaceous, you could get a wall of bamboo by placing them 12-15 ft. apart "on center" (assuming sufficient water). If you are planting with the intent of harvesting for lumber or shoots, grids of 15-25 ft. are in common use (depending on the species in use) to allow sufficient room to work.

GROWTH

These bamboos grow all year long. From approximately October to May, the plants are growing underground, forming their new buds. The other part of the year, approximately May thru October, the plants grow above the ground. This is when the buds break dormancy and create the new, larger shoots.

So if you plant in the spring or summer it is likely that you will get to experience instant gratification. And, you might feel positively brilliant because you put the plant in the ground and - stand back – that plant has doubled in size in only 2 months. Are you gifted or what?

But those shoots were already formed in the container when you purchased the plant. If you had planted that same plant the previous fall, you might not have seen any new growth for months. (Sigh.) But because the plant would have been in the ground, theoretically well planted and getting well watered, that plant would have had the opportunity (out of captivity) to form more, larger, better buds which would, in turn, create bigger and better shoots.

So the real message here is plant as soon as you can.

In Hawaii, if you are planting a well established plant from a container, anytime of the year is fine for planting.

WATERING

About 98% of how well these plants will look is determined by their ability to get properly watered. If you live where it does not rain a lot please consider irrigating your plants.

Though many of these plants will live in less than 40” of rainfall a year, they will not look like you probably want them to look. The only really effective irrigation that we have come across is drip irrigation. Sprinklers are designed to water the ground to a depth of about 2” (think lawn and shrub). Don’t go there. It does not work for bamboos. If you run sprinklers long enough to water the bamboos, you will waste a lot of water and probably drown whatever else is planted nearby. To irrigate these bamboos properly it is necessary to wet the entire root-ball/rhizome which can be as much as 3 feet in depth, and will have a diameter slightly larger than the footprint of the bamboo at ground level. The “feeder roots” will extend from the rhizome anther foot or two.

IRRIGATION

We HIGHLY recommend using a drip irrigation tubing called NETAFIM. It is irrigation tubing that has the emitters already in the line. While there are probably other good products, we have had great success with this system so we try not to reinvent the wheel.

For hedges that are planted in a line, we run 2 parallel lines of Netafim on either side of the plants. Depending on soil conditions, particular species, and environmental conditions, we run these lines one hour a night, or the same one hour every few days. This is cost/water effective, the entirety of the plant is properly irrigated and though it takes a bit more time/money to set up, the maintenance is minimal and the plants will thank you for it.

For single plantings we recommend using a double ring of NETAFIM coming off of a “main” irrigation line (generally a ¾” or 1” poly line).

We recommend using a filter at the “source” of the irrigation water, and a “flush valve” at the end of each run. For details about the parts of this system go to netafim-usa-landscape.com/Landscape/typical_layouts.php. While their layouts are designed for an entirely different kind of planting, you will clearly see the elements and organization of the system.

FERTILIZING, COMPOST and MULCH

Clumping -Non-Invasive - bamboos do most of their above ground growth during the "summer" (in Hawaii this is roughly May-October). Starting in April, we recommend fertilizing with an organic - quick release - fertilizer with an application every 4-6 weeks, depending on rainfall/irrigation. During the first season of growth we recommend using a fertilizer with a Nitrogen value of no more than 10. After the plant is established, higher Nitrogen amounts can be used safely. The actual formula (N, P, K), including some particular complement of minor nutrients and minerals should be determined by your particular soil type - consult your local nursery, horticulturist, agronomist, USDA Soil Conservation Service, or agricultural extension service agent (usually through a university). Whatever formula you choose, be careful with Boron - it should only be used in very low dosages.

Healthy soil is our greatest resource for healthy plants. Compost and mulch result in healthier soil, healthier plants, and ultimately in less work. If applying fresh (green) wood-chips as mulch, make sure that there is ample Nitrogen underneath the mulch to feed both the microorganisms and the bamboos.

PRUNING and THINNING

Starting after the second summer of growth, it is good for the bamboo to be thinned out a bit. Take away only a few of the oldest canes (these will most likely be the smallest in the clump). Do not take more than 1/3 of the total mass of the clump, and do not take any of the newest growth. Once you have decided which canes to cut, cut them near the base, just above a node, which is the 2nd or 3rd node above the ground.

After this initial thinning:

1. You can just leave the clump alone, and with sufficient water and occasional fertilizer it will be OK. Canes within the clump will eventually die and decompose, but the clump, as a whole will most likely continue with vigor.
2. You can thin the clump out every year or two or three - again being careful not to take too much of the newest (youngest) part of the plant, as that is the most important for its future good health.
3. You can thin the clump each year carefully making sure that there are no canes over 3-4 years of age. You can also cut out any canes that are under size, or going in a direction which you don't like (like too close to the house, or too close to the path, etc.). The 3-4 year old canes are at their peak of strength if you are interested in using them for any kind of craft or construction purpose.

You can also prune out branches to reveal the canes or to create a more airy feeling. If you are of a mind to have a highly manicured hedge you can use hedge trimmers to create whatever shapes you like (this is more easily accomplished with the smaller varieties - Bambusa multiplexes, B. glaucophylla, etc.). This shaping can become topiary for those that are so disposed - check out what they do in Thailand with Monastery Bamboo (T. siamensis).

Keeping a "LARGE" BAMBOO in a "small" space

It is possible to keep bamboos smaller than their normal size by over thinning. If you cut out sufficient plant material, including some of the newer growth (you will have to determine the actual amount by trial and error), you will diminish the plant's ability to make larger canes in the following season. We recommend waiting until the bamboo has gone through two full growing seasons before starting to do this.

- If you take an existing, well established clump & clear-cut it (i.e. cut every cane at just above ground level), that clump will put up numerous small shoots in its following summer. Succeeding generations of canes will increase in size year by year. At some point in this succession the canes will approach the size you desire. At this point in the process you can effectively keep the bamboo at that size by selective pruning - this selectivity will include some (but not all) of new growth, and some of the older canes as well. Again, trial & error will be your best teacher.

BAMBOOS IN POTS - outdoors and for interiorscape

Bamboos are used in containers, both in the interior and out of doors. Not all the species are easily adaptable to this usage but a great many of them are.

At the nursery, we use black plastic pots because they are cheap and available. They are not designed to keep plants in over a long period of time. If you are keeping a plant (not just bamboos) in a container we think you should transfer the plant into a pot that "breathes". The old-style unglazed terra cotta pots are perfect. They allow the roots to stay cool and allow moisture and oxygen to move freely. Bamboos like to be wet and then dry out. Make certain the pot has adequate drainage. Make certain that your planting mix is not too dense or it will retain too much moisture. If they are kept wet continually the new buds are likely to rot. This will prevent new growth from occurring. Bad bad, very bad. Try lightening your mix with black cinder (if it is available) or perlite. Do not bump up the size of the pot radically. This will generally encourage over-watering and will again result in a high probability of rotting the new growth. We generally move from a one-gallon pot to a 4 or 5 gallon pot. From there we often jump to a 10-gallon pot.

Outdoors

Imagine yourself in a black rubber suit out in the sun. Then think of your plants. Especially if your plants are outdoors, please take them out of those black plastic pots. Their poor little roots are baking as we speak. And when you water them, those roots stew.. not a pretty picture. If you must leave them in those pots make certain that the pots are not in direct sun. Place the pots in baskets or throw palm fronds on them. Anything. It's also easier on the plant, though not essential, to be in indirect or filtered light.

While plants in the ground tolerate a substantial amount of abuse gracefully, plants in pots, especially those in the sun, are less forgiving. Depending on the size of the plant in relation to the size of the pot, as well as your particular environment, these plants might need to be watered daily. Best time is early morning or late afternoon. If you are watering during the day and are using an outdoor hose please make certain the water is not hot.

Interiorscape

One of the most important things to keep in mind is that when you go to the mall, or the doctor's office, or a nice restaurant, and you see those lovely perfect looking plants it is highly likely that those plants are being rotated. If you want interior plants looking primo at all times we suggest you have 2 sets of plants that you move in and out from time to time. This is what the professionals do and it is what works. However, if you have realistic expectations and remember that your plants are living creatures not all that different from you (with good hair days and bad hair days) you can work around it.

Once more we would like to stress the advisability of removing the plants from their plastic containers and planting them in a well drained mix. It seems better to us to have to water more often than to risk waterlogged plants. We also like to keep a bit of air moving under the planter and so for smaller containers we lift them from their saucers on chopsticks. For larger containers find some larger dowel or some other appropriate material. You will have to determine what the correct watering regime is for your particular situation. Often, especially in the cooler months, once or twice a week is adequate. In the warmer months (during the shooting season) it might become necessary to water your plants more often. They will tell you if you stay in communication with them.
The tropical bamboos are not low light specimens. You will need well-lighted space to grow them indoors. Professional interiorscapers often light them when there is not adequate natural light available. We've been told by one of the masters of large installations that lighting them from below as well as above is a major help, but we don't know of our own experience.

Please do not try keeping interior plants in hermetically sealed environments. Air motion is essential. If your doors and windows don't open don't even try it. It is an exercise in futility.