Yes, most of mine are in the ground here, and I sure don't have to water them in the summer, when our weather is probably very similar to yours in Malaysia. But here in Florida we are classified as a "semi-tropical" climate which really means that half the year we are tropical and the other half we are temperate.
In spring and fall we can go weeks with little or no rain, so I do need to water them then. We have very sandy soil that retains little water so that is another factor making it necessary to water. How is your soil there? If you have lots of organic material in the soil, it will retain moisture well, and also you most likely have high humidity year 'round which helps keep things moist too.
