What is the meaning of なす? Specifically when preceded by a color

Question

I came across this phrase in a book:

緑なす半島

Obviously (and also confirmed by Weblio) it is describing a quality of the peninsula, but I'm curious as to what exactly it means, and how/when it can be used.

I found a forum discussion on its use as compared to なる, but it doesn't seem to me to be used in the same way as where I found it. (It generally concluded that is was a transitive version of なる...which I can't say is wrong, but I don't think I really understood what they were trying to say, and I think it requires a particle {を?} in order to be used like that.)

Answer 1

In this case, なす appears to translate to something like "made" or "like" (as in, "made-green" or "like-green" in regards to the growth of foliage.) 緑なす can also relate to one having glossy, dark hair.

But I would suggest that なす preceded with a color does not always equate to this type of usage. 緑 seems to be special as it relates to natural colors or foliage (see second definition on this dictionary entry.)

In regard to the actual use of なす here, it may historically be a remnant from poetic usage. See this possible explanation (No.640) for more information (though this is only, evidently, speculation.)

Although it's not preceded by a color, this possible explanation cites a use of なす in a particular poetic verse by 加藤楸邨{かとうしゅうそん} (reference):

灯を消すやこころ崖なす月の前

Answer 2

nasu is a suffix that is attached to nouns and means "like" or "similar to". Some of these phrases are more common than others such as 山なす大波 "a mountain-like large wave".

But in this case, "midori nasu" is a common phrase meaning for trees and plants to grow in abundance. So it is a peninsula rich in plant life.