Bunga kertas (Bougainvillea) – it’s called Bunga Kertas (Bunga=Flower Kertas=Paper) in Malay due to the flowers look like they are made from paper.
Possibly Alpinia? The sign near this plant stated so:
Different colour, in purple-green:
Similar plants of purple, magenta, lilac and pink colours:
There are more plants that I didn’t manage to photograph. I can probably spend at least 1/2hr there to a few hours. There are shaded areas where one can sit and relax. It’s usually not packed unless there’s event there. In fact, when I went up in the late afternoon, there were only 8 people besides me in the garden.