Improving City Life withVertical Greenery Technology
Increasing urbanization and more ecological contradictions make us realize that plants not only beautify our life, but also help to improve the environment, such as improving microclimate, conserving soil and water, reducing noise pollution, absorbing and decomposing pollutants, and so on. Vertical greenery is an effective way to improve the environment when land use keeps stable and cities need to enlarge green place and to raise the green coverage rate.
In recent years, vertical greenery technology in China begins to develop. While China learns advanced skills from other countries, it also develops its own technology that is suitable for itself. Modern Vertical greenery can be applied in more areas such as vertical façades, fences, posts and more plants such as vines, shrubs can be used. In modern greenery there are equipment of auto-sprinkler irrigation, illumination and decorative materials. All these form a better landscape in a shorter time.
We will elaborate in this preface one of the most advanced vertical greenery method—the green wall and its major technology, the use of plants, its maintenance and other relevant matters.
Like other ways of greenery, plants are the core in vertical greenery. Therefore, how to choose and arrange plants is very important. In choosing plants, their habits should be carefully considered. Also, designers need to consider the environment the plants will be living in and their appearance and functions, to create suitable growth conditions so that there are more suitable plants and the whole landscape becomes more beautiful.
I. Major Technology
Modern green walls employ mainly four planting methods, i.e. module, slant plant grooves, framework and water planting. In order to keep consistent greenery, evergreen plants are frequently employed.
It is the way through which plants are arranged into many modules. It is also the best way to arrange patterns and create visual effect. Arranging plants into standard module-like plates which hold special nutrients and are fixed on the medal framework by hooks or screws, and equipped with a drip irrigation system, this model has many advantages such as higher coverage, higher survival rate and more species. Also it can produce various patterns, cost little time to build, keeps on for a long time and is easy to maintain, thus creating the best visual landscape.
Ideally, plants arranged on the wall should be cultured on the ground to two months to achieve the best results. Herbaceous plants and small shrubs with high coverage, low root and nice visual effect are the best choice. For interior space,Epipremnum aureum, Chlorophytum comosum(Thunb.) Baker, Aglaonema modestumSchott ex Engler, Syngonium podophyllum Schott, Rohdea japonica (Thunb.) Roth, Fittonia verschaffeltii(Lemaire) van Houtte, Anthurium andraeanum Linden, Spathiphyllum kochii Engl. et Krause, Dracaena sanderianaSander ex Mast., Zeuzera coffeae Nietner, Monstera deliciosa,Pteridophyta, etc are the best choice. Outdoor dark sides mainly employ Alstonia scholaris (L.) R. Br., Ophiopogon intermediusD. Don, Reineckia carnea (Andr.) Kunth, Ophiopogon bodinieri, Pteridophyta, Arrhenatherum elatius(L.) Presl var. bulbosum (Willd.) Hyland f. variegatum Hitchc., Ophiopogon japonicus, Iris tectorum, Asparagus cochinchinensis(Lour.) Merr, Philodendron selloumKoch, Monstera deliciosa,Alocasia macrorrhiza, Eupatorium fortunei, Panax pseudoginsengWall. var. notoginseng (Burkill) Hoo et Tseng,Calathea roseo-picta (Lindl.) Regel andWedelia chinensis (Osbeck.) Merr, etc. On the other hand, sunny sides use Duranta repenscv.Dwarf Yellow, Excoecaria cochinchinensis Lour., Serissa japonica(Thunb.) Thunb.,Ficus microcarpaL. f. var. pusillifolia Liao,Ligustrum quihoui Carr., Hibiscus rosa-sinensis Linn.,Loropetalum chinense var. rubrum Yieh, Photinia serrulataLindl. var. serrulata,Pittosporum tobira (Thunb.) Ait.,Rhododendron pulchrumSweet, Allemanda cathartica L., Hamelia patens Jacq., Ligustrum japonicum‘Howardii’, Ligustrum × vicaryi, Codiaeum variegatum (L.) A. Juss., Cordyline fruticosa(L.) A. Cheval., Bougainvillea glabraChoisy, Murraya exotica L., Gardenia jasminoidesEllis, Alpinia zerumbet (Pers.) Burtt. et Smith, Chlorophytum bichetii Hort. ex Backer, Dianella ensifolia(L.) DC., Fagraea ceilanica, Zephyranthes carinata (Spreng.) Herbert andEuphorbia milii Ch. des Moulins, etc.
2. Slant Planting Grooves
Plants in slant grooves grow up toward a slant vertical dimension. Grooves are often light planting bags or in hard material that are fixed on metal frameworks.
This kind of walls can house many species. Also it is quick to build and cost relatively less money. It is suitable for those projects with little budget and few requirements, outdoor or indoor.
Perennial evergreen plants with big leaves, high body and nice visual effect are frequently employed. Major indoor plants are Anthurium andraeanum Linden, Syngonium podophyllum Schott, Aglaonema modestum Schott ex Engler, Rohdea japonica (Thunb.) Roth, Fittonia verschaffeltii (Lemaire) van Houtte, Epipremnum aureum, Monstera deliciosa, etc. Plants for outdoor shady side areAlocasia macrorrhiza, Pteridophyta, Iris tectorum, Monstera deliciosa, Alstonia scholaris (L.) R. Br., Draceanaarborea, Cordyline fruticosa (L.) A. Cheval., Excoecaria cochinchinensis Lour.,Calathea roseo-picta (Lindl.) Regel, while those for the sunny side are Hibiscus rosa-sinensis Linn., Acalypha wilkesianaMuell.-Arg., Codiaeum variegatum (L.) A. Juss., Buxus megistophylla Levl.,Euonymus japonicus Thunb. var. aurea-marginatus Hort., Ligustrum lucidumAit, Photinia serrulataLindl. var. serrulata, Nandina domestica Thunb., Mahonia fortunei (Lindl. ) Fedde, etc.
3. Water Planting
In this method, plants are planted on the felt which sticks to the surface of the wall. The key is to ensure that the plants can take their roots into the felt and therefore grow up naturally.
Such kind of walls often equipped with leaking irrigation system. These walls are light, thin and easy to be built in curve form. Both indoor and outdoor spacesuse this kind of wall.
This kind of walls mainly uses plants that are suitable for water culture. Plants used in interior space are Pteridophyta, Dracaena sanderianaLotus, Dracaena sanderianaSander ex Mast., Epipremnum aureum, Fittonia verschaffeltii(Lemaire) van Houtte, Syngonium podophyllum Schott, Rohdea japonica (Thunb.) Roth, Monstera deliciosaand Alocasia macrorrhiza,while those used in outdoor are Alstonia scholaris (L.) R. Br.,Dracaena marginataLam.,Cordyline fruticosa(L.) A. Cheval.,Ophiopogon bodinieri, Asparagus cochinchinensis(Lour.) Merr, Zephyranthes candida(Lindl.) Herb.,Dianella ensifolia(L.) DC.,Excoecaria cochinchinensis Lour.,Codiaeum variegatum (L.) A. Juss., Zebrina pendula Schnizl.,Gardenia jasminoidesEllisandAglaia odorataLour.
4. The Framework Style
This kind of wall use metal frameworks and ropes to help the plants climb onto the wall. It is mainly used in outdoor space or indoor space with enough natural light. It cost little money, has a high survival rate and is easy to build. But it needs two years to create a wide coverage. Also the species ready for choose are few. Changeable patterns are hard to arrange in this way.
Perennial evergreen vines such asPseudocalymma alliaceum(Lam.) Sandwith, Pyrostegia venusta (Ker) Miers, Campsis grandiflora(Thunb.) Schum., ParthenocissusPlanch., Ficus pumila Linn., Wisteria sinensis, Hedera nepalensis K. Koch var. sinensis (Tobl.) Rehd., Trachelospermum jasminoides (Lindl.) Lem., Morden cvs.of Chlimbers and Ramblers, etc. are often employed.
2. Design and Installation of the Metal Framework
Basic metal frameworks are designed strictly in accordance with the Designing Standards of the Metal Framework.First of all, the metal framework and the wall must be designed based upon specific features of the building. If there is no annex, the wall needs a self-propped metal structure. Second, minimalize the use of metal to the extent that it can support the weight of the plants. Third, the metal employed should has high weldability. Four, the frame and its installation should conform to the Standards of Construction and Accepting Check of the Metal Framework. Fifth, the framework installed should has a pull-out capacity no lower than 10KN and a shearing resistance no lower than 10KN.
3. Design and Installation of the Auto-dripping Irrigation System
(1) The water it uses could be the municipal water, reclaimed water or purified rain water.
(2) The whole wall is divided into many irrigation areas according to the area of the wall, the habit of the plant and the seasonal change of the weather, to meet appropriately the needs of the plant.
(3) The irrigation time should be controlled in accordance with specific season, environment and habit of the plant.
(4) There could be a micro-sprinkling system to ensure the needs of the foliage.
(5) There should be a check of the water pressure before the construction.
(6) Irrigation pipes should be installed in accordance with the design.
(7) Electromagnetic valves and filters should be arranged based upon the division of the plant.
4. Construction and Adjustment
The wall should be waterproofed before installation, while pipes and other pre-installed equipment should be installed before the waterproof process. The equipment installed after this process should be annexed under them with a piece of reinforced waterproof shield which should be protected through the installation.
5. Installation of the Culture Elements
Culture elements are placed in the plates, which are hooked onto the metal structure. Water pipes should be fixed within the grooves of the plates. If installed in a high attitude, there should also be anti-falling measures.
6. Installation of the Auto-control System
(1) Find out the right type of the controller. Every one of them controls an area of the wall, thus ensuring a balanced water supply.
(2) Set the irrigation time based upon the habit, the area and the dimension of the plants and the changing weather.
There are three kinds of maintenance, i.e. check and maintenance of the plants, maintenance of the irrigation and drainage system and maintenance of the metal structure. Although selected plants are easy to maintain, six times of maintenance every year are necessary since the plants need two years to adapt themselves to the new environment. This frequency will keep on for five years to make sure that the plants can survive the new environment. From the sixth year on, there could only be four times of maintenance every year.
III. International Development of Vertical Greenery
1. Oversea Development of Vertical Greenery
As a key of the global trend of returning to the nature, vertical greenery has gained great popularity throughout the world.
It is clearly prescribed in the laws of many nations that brick walls, plastered with cement or not, shall not exist in cities; and that all walls shall be built as “ecological walls”. Such walls are decorated before them with trees arranged in average space. These trees are interfered with vines supported by metal networks. This kind of wall reaches an appropriate function and saves time as well as resources. In the U.S, there is almost no space without grass, be it the space of railings of a supermarket or a façade of a building. Singapore, crowned as “Garden City”, is totally covered by vertical greenery. In 1991, Tokyo government issued laws on city greenery. The law state that a greenery plan must be proposed when designing a building. In 1992, it issued the “Guide to the Greenery of the City Building”, prescribed many details of city greenery. The “Tokyo Greenery Movement”, initiated by Tokyo Construction, co, ltd., Tokyo Landscape, co, ltd. and other corporations, is well supported by the Tokyo government. The vertical greenery not only benefits Tokyo people, but also attracts many tourists.
2. Vertical Greenery in China
It is now a core policy of the government to build an environmental-friendly society which harmonize the nature and human civilization. For this goal, vertical greenery provides a practical method.
City greenery is now extending itself to vertical greenery from the original ground greenery. Such a change marks a tremendous advance of the conception of ecological building as well as its great potential. Introducing vertical greenery into the city and planning the environment on the basis of city space and buildings will create an unprecedented city landscape, and finally realize the harmony between the city and the human. City economy will also benefit from this development with designers producing more pleasant and agreeable houses. Take Shenzhen for example, if the increased 10% greenery (roughly 1400hectares) is totally vertical, the value of the land saved is 700billion!
We believe that with the advance and prevalence of the new vertical greenery technology, vertical greenery will gain its popularity in the city. In shanghai EXPO, with the conception of energy conservation, ecology and environmental protection;both hosts and guests employ vertical greenery. For the purpose of improving city environment, beautifying city landscape and reaching ecological balance, let unite to progress the vertical greenery technology, thus reaching a better city and a better city life.