The plant itself has conditions that it needs to have met in order to express its color and physiology. Without these, the plant and therefore, a vegetated assembly will not function properly. Which plant species is it? Where is that plant found? What can I expect to gain or discover by selecting this specific plant or plants for an assembly? Depending on the project and its needs there might be limitations to the types of plants based on grower available and native or non-native plants and regulation. Why? This is one of the most critical conditions that much be met. If the climbing mechanism of a plant is not met it may not grow into the vegetated assembly you desire. For example a ground-covering plant may not grow on a vertical wall. The Royal Horticulture Society has a catalog of official colors that are used to identify colors in plants and then possible color schemes for their use.