IronWood Needles?

[MarkP]

There are a handful of varieties but the two most common ones here in Hawaii are casuarina equisetifolia (beach she-oak) and casuarina cunninghamiana (river she-oak). I asked someone from the state who told me that the ones on the beach are the really invasive ones. A year ago you could still buy the river she-oaks from the state arboretum. The guy with the state said they were not really invasive. So, I guess it makes a difference which one you are talking about.