A popular landscaping trend in Thailand is to cover otherwise boring or unnattractive walls with greenery, and this can be seen in both urban and rural landscapes.
(picture above: hanging garden on wooden wall in Bangkok) With hanging gardens, the wall can be constructed so that hanging plants with soil reserves can be fixed to the wall. The plants, with regular water and feed, can then grow to cover the wall in a bright and colourful way. Different plant combinations and colours can be used to give many different facades and effects.
Another way to obtain the green wall effect is to grow hedge type plants that will knit together and are tall enough to cover a wall. There are many different varieties, with different textures and colours.
If you reside in Thailand and have a home or business that needs a green wall or hanging garden, contact ben@thaigardendesign.com or call 080 655 8110 (Thai and English)
I really, really hope you will be succesfull in Bangkok and Chiang Mai. This is the way to fight the urban heat problem! Perhaps you can also show a picture with a wall which uses as little water as possible during the dry season.