Guest or Resident?

This dragonfly has been living in our small garden for some time. I saw him flying around lemongrass bush every time I water the plants. I think lemongrass is the only plant except grasses that is suitable to grow in my little garden. So far I have planted sweet potato (for its leaves), okra, sweet pea, long bean, winged bean, Chinese spinach and kangkung, almost all of them look so "unhealthy".