Bamboo is considered one of the most famous and abundant plants globally. Thanks to its vivid green color, accelerated growth rate, and durability, Bamboo has become very popular for growing in gardens and urban parks, pots, or even in vases inside the house. Depending on the bamboo species, the plants can be used as a building material, as ornamental plants or/and for biofuel (like bioethanol), fabric, furniture, and paper production. Some species even have edible bamboo shoots that animals and humans can consume. Bamboos are usually preferred for creating a natural screening (fence) since they can grow fast and dense.
How to grow Bamboos Outdoors
Bamboo Variety selection
There are more than 1,400 bamboo species globally, from herbs, shrubs, trees, and climbers. There are 2 main types of bamboos: the sympodial or clumping (largely tropical) and the monopodial or running bamboos (largely warm temperate). Their main difference is that the plants of the first category grow as a cluster in one spot and expands very slowly from one place to another, while the second, thanks to their thin rhizomes, can quickly expand over long distances. Depending on the species, bamboos can become quite tall, reaching up to 25-65 feet (8-20 m). Generally, a bamboo of the clumping type usually can gain around 1-2 feet or 30-60 cm per year, while the running varieties can grow even faster (3-5 feet or 90-1.5 m gain yearly). However, there are many dwarf varieties as well.
Some common species are:
Running | Clump-Forming |
Phyllostachys aurea | Fargesia nitida |
Phyllostachys aureosulcata f. spectabilis | Fargesia murielae 'Simba' |
Pleioblastus pygmaeus Distichus | Fargesia murielae |
Pleioblastus variegatus | Fargesia murieliae 'Jumbo' |
Pleioblastus viridistriatus or Dwarf green stripe | Fargesia murieliae 'Rufa' |
Sasa tsuboiana or Scottish Bamboo | Thyrsostachys siamensis or Manastery bamboo |
Sasa veitchii | Bambusa multiplex or Chinese Dwarf Bamboo/ Alphonse Karr |
Semiarundinaria fastuosa or Temple bamboo | Bambusa vulgaris or Buddha’s Belly |
Phyllostachys vivax or Chinese timber bamboo | Himalayacalamus hookerianus or Himalayan Blue |
When selecting a bamboo variety, you are advised to consider the local environmental conditions, the space you have for the plants to grow, and the purpose the plants will serve (e.g., live fence). Furthermore, since the bamboos are grown for aesthetic reasons, plant characteristics like size, color, and shape of the clumps and the leaves are essential.
Bamboo's soil and environmental requirements: Where to plant your bamboo
Bamboos can grow in various soil types but perform best in sandy, loamy, rich, slightly acidic, well-drained soils with a relatively high soil moisture level. Loose soils can allow a faster spread of the plants by allowing the expansion of bamboos' rhizomes. Additionally, the plants can grow successfully in semi-shade but prefer sunny places. When the plants receive enough sun, they grow faster, become taller, and obtain a more vivid green color. Avoid sites exposed to strong winds, withhold water, and are prone to frost.
Propagation and Planting of bamboos
Bamboos can be propagated both with seeds and vegetatively. However, it is easier for an amateur grower to buy a potted plant from a plant nursery (garden center) and transplant it in the chosen-appropriate spot of the garden. The plants are usually sold in larger pots of more than 2 liters. Generally, spring (or early summer) is the best time of the year for planting bamboos. To ensure a good establishment, avoid planting your bamboos when the weather is too hot or too cold. If we want to create a dense screen, we can place the young bamboo plants around 1 m (3 ft.) apart. You can open a hole twice as wide as the pot size and a bit deeper (1-2 cm or 1 in). There is no need to open a deeper planting hole because bamboos are generally shallow-rooted plants. You can remove the plant from the pot gently, spread the roots a bit (gently), and place it on the ground. You can refill the hole with soil or a mix of soil and compost, press gently to improve the contact of the roots with the soil, and reduce transplanting stress and water. Mulch can be added around the plants to hold in moisture.
Control Bamboo Spread
The plants, especially those of the running type, can expand quickly with their rhizomes. This ability may be desirable during the first years of plant establishment but usually becomes a problem later on. More specifically, bamboos can "draw" and kill most other plant species. For this reason, while difficult, it is necessary to control their growth in home gardens. An option is to dig up, remove, or chop the plants' runners. To ensure that our plants will grow only in the desirable area, we can create-install a vertical barrier at least 2-3 inches (5-7.5 cm) deep into the ground (and 2-3 inches or 7 cm high) before planting bamboos. If we have chosen larger plants (e.g., Phyllostachys), we have to ensure they have enough space to grow. In this case, the barrier should leave an area of more than 2.5 m (8 feet) in diameter for bamboos to expand.
Water and Nutrient Requirements of Bamboo
Bamboos thrive in rich soils with sufficient soil moisture. However, after establishment, the plants need limited assistance. More than 700 mm of water is generally necessary annually, while the optimum ranges between 1500-3800 mm. As a result, at least 1 inch (2.5 cm) of water (rainfalls or manual watering) weekly is needed for good plant growth. Under such conditions, bamboo plants can become taller, while on the contrary, drought, especially in the young stages (first 2 months), can lead to defoliation. During the warmest months, plants may need watering once every 2 to 4 days. However, it is essential to avoid planting bamboo in poorly drained soils. Older bamboos are more drought-hardy. Irrigation with sprinklers is possible, but drippers are the most optimum choice.
To nourish our plants and assist their growth, we can add controlled-released fertilizer pellets (1 tablespoon per plant). However, this may not be necessary during the first year if we have added compost to the planting hole. In later years, fertilization can be performed once or twice from early spring until early autumn. Usually, the application of a nitrogen-rich fertilizer in early spring is necessary, while later on, a balanced fertilizer can be used. It is advised to leave the fallen leaves on the spot since bamboos can be benefited from the nutrients they contain.
Deadheading and Pruning
As bamboos get older, we may need to "cleaned them up" from dried leaves or canes. By cutting them out using a pruning saw or shears, we help the plants regenerate, prolong their life span, and maintain an attractive look. If the clump has become very dense, we can thin it out by removing some canes from the base. Additionally, we can cut the tops of the plants to control their height and encourage the production of healthy and ample foliage.
We may need to perform deadheading in older bamboo plants to remove any flowering shoots. Despite the nice appearance of bamboo flowers, flowering can weaken the plants dramatically and lead to defoliation or even plant death. If we observe that the whole bamboo clumps flowers, we can cut it to the ground during spring. We may also add nitrogen-rich fertilizers and water to encourage the regeneration of the plants.
Pest and Diseases: Common Problems of Bamboo
Bamboos generally do not face many problems, especially from biotic stresses. However, some issues that the bamboo growers may have to deal with are the following:
- Rust disease common symptoms: orange to brown pustules on the foliage
- Root rots common symptoms: chlorotic and wilting foliage, defoliation.
- Bamboo aphids common symptoms: plants can have poor growth, and we can spot the insects on the leaves. Usually, the foliage can be covered by a sticky substance or/and sooty molds.
The appearance of some yellow leaves is expected since the plants renew their foliage. However, observing extensive chlorosis on your bamboos may be a sign of stress (drought or waterlogging, nutrient deficiencies, or extreme temperatures). In a case of an extensive problem, you are advised to consult a licensed agronomist.
Growing Bamboo In Containers-Pots
If you wish to have potted bamboos in your yard or your balcony, choosing the best varieties that will grow and spread less is best. Start with smaller plants. Depending on the original size of the plant (and its root ball), it is best to transplant it into a large container (45 cm or 18 in wide and deep). Additionally, since bamboos tend to become very tall (depending on the species), it is best to choose a heavy and wide container to prevent the potted plants from tipping over. Moreover, we need to open holes at the bottom of the pot allowing drainage of the extra water within minutes.
To improve drainage, we can add crockery or gravel to the bottom of the pots. Preferably, use a loam-based potting soil mix with some garden compost. Transplanting should take place during springtime. Some amateur growers soak the bamboo root ball in water for 1 hour before transplanting it. This may be necessary if the plants we bought seem drought-stressed.
Choose a sunny place to place your newly potted bamboos. This will accelerate plants' growth. You may avoid areas exposed to strong winds. Do not forget to water abundantly after transplanting. While bamboos can withstand temperatures close to 0 °C (32 °F), it is best to move our pots to a sheltered site and protect the root system from frost by using bubble wrap. If the temperature drops below 4 °C (39,2 °F), we can place our containers indoors until the temperature rises again.
We can add controlled-released fertilizer pellets to nourish our plants and assist their growth. However, this may not be necessary during the first year if we have added compost to the potting soil. In later years, we can add a general liquid fertilizer once or twice from early spring until mid-autumn. Remember that bamboos are sensitive to drought, especially in the early stages (first two months after planting), so watering should not be neglected throughout the growing season. During the warmest months, plants in containers may need watering daily or once every two days. Drought stress can lead to plants' defoliation and early plant death.
As the plants grow may need to be repotted in larger containers after a few years. Finally, since bamboo can be propagated vegetatively, we can divide them and replant them in different places.
References
- https://www.hindawi.com/journals/tswj/2020/7284203/
- https://www.rhs.org.uk/plants/types/grasses/bamboo/growing-guide
- https://erdb.denr.gov.ph/wp-content/uploads/2015/06/denr_v9.pdf
- https://plants.ces.ncsu.edu/plants/bambusa-multiplex/
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