Normally, chill and bitter melon are all one-year plants. (but chill can grow through to the second year under QLD's warm weather).
This year there are plent of rain in QLD, we have got a lot of bitter melons and chills, especially the bitter melon. We eat bitter melon nearly everyday during this summer but there are still too many so that we have to give some to friends.
If the plants can get plent of sunshine and fertizer, they will grow well.
You can plant what you want in your garden except marijuana.
Depends on where you live in Australia. In QLD, it may be too hot to plant orange. Many people plant Mango tree in their garden.