BAMBOO FOR TERRACE AND ROOFTOP

We get many questions about using bamboo on terraces and rooftop gardens in pots, tubs and containers. A bamboo in a pot may look nice but remember that it also has some drawbacks; dehydration, yellowing and frost damage lurk. The root ball is above ground and exposed to much lower temperatures in a frost period than it would be if the same plant is in the ground. Irregular watering and fertilization reduces plant vitality. Even with the most hardy species we cannot guarantee that it always goes well. If possible, it is always preferable to plant bamboo into the ground. But on a roof garden or paved terrace above a parking lot, there are no other options. To get the best results in that case and to reduce the risks we recommend a big enough container, adequate soil quality, periodical nutrients and water and of course the right species.

We can provide you the right species and size of bamboo, containers, soil and irrigation. We can deliver and ship it to you as a do-it-yourself package or install it at your place by our bamboo landscapers.

(1) Container. It is important to purchase a sufficiently large plant container, preferably with an inner diameter of at least 50 cm. Provide wall insulation (eg. Polystyrene XPS or PIR). The outer size will then go to 55 / 60 cm. For roof garden / terrace projects we can deliver customized planting containers that meet these requirements. For projects we provide customized planting containers for roof and terrace gardens in combination with project design, advice and realization. In the past we have delivered planting containers made from wood, Cor-Ten steel, sandwich panels, with f.e. stucco etc.

(2) Soil. Use the correct soil mixture to keep bamboo also on the long term in good condition. Standard potting soil from the local garden center is not suitable. Our special bamboo substrate we use ourselves in bamboo production is available at our shop in 70L packages, this is mixed with hydro-grain 40L. As winter protection for the roots, it is sometimes recommended to use an insulating layer of French pine bark as top layer. All these products we have available in our bamboo store

(3) Nutrients. Annually use 2 to 3 times Bamboo Food, an organic fertilizer in order to keep the plants in good health. This fertilizer is available with us in 2.5 L and 5 L buckets. This is the fertilizer that we use ourselves in cultivation, besides the main nutrients it holds the complete spectrum micro-elements, mixed with volcanic powder.

(4) Water regularly so the topsoil is moist. In case of project plantings consider to apply an automatic watering system with a water timer and irrigatie lines. Water timers, irrigatie lines and appendages can be installed as a plugin system by our landscapers.

(5) Species. Select an appropriate species that suits your situation and wishes, ask for expert advice or visit the nursery during the sale days. Many Fargesia’s can be used in planting containers; the preference is given to the strongest species. If the terrace is summer and winter in sight a non-leaf rolling bamboo is most desirable. One of the best types is Fargesia dracocephala 'Rufa', this species is a busy, fresh apple green leaved species which is year around attractive. This species can grow to about 1.5 m to 2 m in a container. By pruning, this plant can be kept much smaller. Where a higher, dense bamboo planting is desired consider for more sheltered spots Fargesia robusta 'Campbell'. This bamboo has an upright growth habit, fine leaves and sturdy, beautiful stalks that are initially dark green with paper white bracts. Fargesia sp. Jiuzaighou-1 can also be used on terraces and roof gardens. It’s culms colour deep red in the sun. In winter this plants is temporarily more transparent. This applies to a lesser extent the new Fargesia nitida hybrids 'Black Pearl', 'Volcano' and 'Pillar'. The murieliae x nitida hybrids can be used in containers such as the stronger Fargesia 'Winterjoy'.
For larger containers one can also work with the thick culmned species of the genus Phyllostachys and Semiarundinaria. In particular, it is Phyllostachys aureosulcata 'Aureocaulis' and 'Spectabilis' interesting, along with Phyllostachys bissetii, humilis and nuda. The stiff upright species Semiarundinaria viridis is a good option for sheltered locations.

BACKGROUND ARTICLE ABOUT BAMBOO IN CONTAINERS EN TUBS

In recent years there increasing demand for the use of bamboo in planting containers on roof gardens, terraces and paved areas in the hotel and catering industry. On a roof plantings are exposed to a more extreme climate. The conditions in a pot vary much stronger than in the ground: the variation between dry and wet, and especially between hot and cold are more extreme.

Based on our experience, we have developed an approach to maximize the chance of success. With the right measures, species like Fargesia dracocephala 'Rufa' Fargesia robusta 'Campbell' Fargesia sp. Jiuzaighou, Fargesia hybrids and various Phyllostachys and Sasa species are used in these situations.

It is important to note that virtually all plants, including bamboo, grow most vital in the ground. If this option fails then there are, with some risks, opportunities to use bamboo in permanent planting containers.
After a single night of severe frost a pot can already be completely frozen while it takes two weeks for a bamboo in the ground before the entire rootball is frozen. Due to a frozen rootball the plant cannot absorb water with the roots while the foliage evaporates under windy or sunny conditions. If no moisture can be extracted by the roots for the leaves the plant will dry out. This phenomenon applies to all evergreen plants in pots.

Roots of a plant are often the weakest link in terms of hardiness. If it is not possible to plant directly in the soil than try to use a large container, fill it with humus-rich, well-drained substrate and place the plant in the pot out of the wind, preferably in a frost-free place during periods of frost in winter.

Always have a water dish under the pot stands or manually water regularly, even in winter during windy/dry periods (not during periods of frost) and especially in the summer. Even during rainy periods in the summer, it may be necessary to give the bamboo extra water as much rainwater runs over the canopy and never reaches the rootball!

PRIVACY IN THE CITY

Increasing urbanization affects the future forms of gardening and the use of plants like bamboo. The modern city dweller has a deep need to have some sort of living green in his or her environment. The garden size for new homes is still decreasing, leaving not much more than a terrace and an increasing number of homes have to do without an outdoor area with earth, but instead have a hard surface such as roof gardens, parking garage and balcony gardens. In these situations, there is a clear need for the creation of an outdoor place with sufficient privacy. Shielding or removing an unsightly view can be created quickly with bamboo. Bamboo is a plant valued for its strong, evergreen character with fine, fragile leaf texture and vibrant colors.

RULES

There are a number of preconditions that must be met to provide a successful bamboo planting on roof gardens. First, it is important to make consultation with a bamboo specialist. The species of your choice is related to the desired height, leaf size and plant form, together with the microclimate at the location; what is the level of sunlight, wind exposure etc.

HOUSING

There are also some requirements for planting containers. The dimensions must be sufficiently large (preferably at least 40 cm deep). Width for the rootball at least 50 cm, preferably wider in order to reduce edge effects. The isolation of the inside of the walls with a high insulation value reduces freezing of the root system. Furthermore, it is important that the containers are made of a durable, high quality material that can withstand root pressure in the long term.

WATER MANAGEMENT

When using rhizomatous species, additional measures are sometimes needed to prevent ingrowth of rhizomes in roofing. In addition, it is of great importance that the bins have a good drainage system to prevent water stagnation (a saturated soil lacks oxygen and causes root rot). Regular watering is vital for bamboo planted in containers. This can be done manually but for bigger projects, an automatic irrigation system enables you to provide year around the right amount of water. This can be carried out with water-saving techniques like driplines, a seasonal water timer and a soil moisture sensor. It is also important to know that even in winter, when it is not freezing, the containers must be sufficiently moist to avoid drought damage. With manual watered containers, this is sometimes forgotten.

NUTRIENTS

It is of course important to choose the optimal substrate for the bamboo to grow in for many years with a stable structure. The bamboo substrate we use ourselves in bamboo production we also sell at our nursery shop. It holds moisture and nutrition good and drains sufficient. Where the permissible roof load is low, we can provide a special lightweight substrate. Container planting is an open system in which nutrients by abundant rainfall, drainage and absorption of the plant from the substrate disappears. If shortages occur which are not manually added, deficiency diseases will follow such as chlorosis. The vitality of the plant decreases, making it susceptible to all kinds of damage such as aphids, spider mites, etc. As for nutrient supply slow-acting nutrients are recommended. Our bamboo fertilizer ‘BambooFood’ also contains minerals from lava basalt powder. Bamboo Substrate (70 liters) and fertilizers (Bamboo Food, packaging 2.5 and 5 liters) are available at the nursery.

FROST PROTECTION

Permanent evergreen plants in containers, such as bamboo, need extra care. The growing conditions in a container are more extreme than in the ground, with frost penetration in the roots / root zone of the plants where temperature drops quicker below zero compared with plants in the garden. If the root ball of bamboo (or other evergreen plants) in a container is completely frozen through the leaves can no longer evaporate moisture which might result in brown leaves (freeze-drying). Often the best choice bamboo will recover again during Spring. In winter it is advisable to cover the planting at the base with an insulating layer of pine bark or wood chips. Also it is, as mentioned previously, useful to isolate larger planting trays on the inside with PIR or XPS.

In contrast, the summer sun warming is stronger, which stimulates growth earlier. There is often more wind and sometimes lengthy shadow of surrounding buildings during the growing season. All together, bamboo grown in containers is often more compact than in the ground. Often, there is some more leaf damage after the winter in comparison with the open ground but that varies with location and selected species.

MAINTENANCE

For larger bamboo container planting projects it is essential to prepare well. It is wise to make arrangements and possibly a maintenance contract with a landscaper which covers irrigation, drainage, feeding and pruning.
In books and periodicals it is sometimes recommended to take out the bamboo, cut it in parts and replant a vital part again. In my opinion this is rarely necessary and this often leads to growth problems and die-off. It is sufficient to prune out the oldest culms every 3 to 5 years, then enough room will be available for the plant to refresh with yearly new shoots. By applying a dressing of compost and BambooFood in between the culms, growth remains healthy.
If the potential risks and required growing conditions are taken into account, together with the right guidance and attention a beautiful and functional result with bamboo will be achieved.