I am showing this series of photos to highlight an issue I mentioned before. I commented before that the Bauhinia kockiana (Family: Fabaceae / Leguminosae) should not be planted in troughs like these, which are similar to those on pedestrian overhead bridges and flyovers and so on, with very little soil volume.
In my opinion, it is a mistake to begin with. Just look at the pale green leaves with very obvious interveinal chlorosis. It would look good initially but over time, the fast growing, heavy feeder climber would take up all the nitrogen, iron etc from the soil, resulting in such nutrient deficiency symptoms. It would take lots of fertilizers and regular fertilizing to correct this problem and maintain a healthy looking plant with profuse flowering. Whether it is worth it or not is up to the individual.
By the way, some of the leaf tips are black and this is likely symptomatic of fertilizer burn and / or insufficient water. I know it sounds like a paradox but the fertilizer burn may occur if the quantity of fertilizers, especially inorganic types, used is too excessive and there is inadequate water given to the climber after the fertilizing. For a plant to absorb the ionic nutrients effectively, water is needed to transport them up the plant tissues.