OK, with a plant – actually a whole genus of tropical herbaceous plants that produce pretty flowers – with a name like this, the first question is quite obvious… is it costive?
Actually, we may assume that it is not – it’s related to ginger, and while that’s a non-binding relation, we may assume that something runs in the family.*
The various species of costus are in fact used for various medicinal purposes. Costus igneus (fiery costus, or spiral flag) is thought to build up insulin in the body. And Costus speciosus has been claimed to be good for treating fever, rash, asthma, bronchitis, and intestinal worms. The Kama Sutra says put it on your eyelashes to be sexier (would Benylin do?). Of course, that claim may be specious.
For the ordinary flower buyer, however, the main feature of costus species is that they are pretty. They often have a flame-like look to them (which would remind one of the word holocaust except that that word is not now used to refer to burnt sacrifices, as its transferred meaning has become entirely dominant). They are lively, hot-looking flowers, suitable for adorning a señorita’s hair – or the coat of arms of Nigeria. In short, they seem almost utterly at odds with their Greek-derived name, which is rather cold and a bit hard, echoing cough and a bit of tussive and mixing up scouts.
There are probably other echoes and wordplays available; I will leave you to work them out. Perhaps you may wish to do so while meditating on a potted Costus speciosus (you can easily buy them – in the US they cost $15–$20 potted).
* For those unfamiliar with the word costive: it means “constipating” or “constipated”.