Not at all, but they need a bit more space so I would recommend minding the gap :D I planted too many of them too close together and some of them fell down. Perhaps, they would be bigger too if they had more space or more sunny spot. Just like trees, they grow only as big as the space available for them dictates. And I guess timing of when to plant is important too, other than that they are quite easy to grow.
I would have to spend a bit more time in tropics before I know for sure, plunging into the jungle streams sound fun!
:D
How far apart should they be? I am wondering if we have enough space or a suitable area for them now.
The jungle streams in the hills are great - and the water cold - down closer to the sea not so great... crocodiles :)