I've found them in both zones, but mostly in Continental Highlands. All I can say is look in out of the way places. It looks like a dark spot from far away, and a tiny face on the ground up close. Though its more rare, its actually easier for me to see than Mountain Floret (which is basically invisible).

i found 2 of thems at same area
near castle walls at 2. map
will give coordinat
u can make elixir with it. i didnt create any
what we can do with it ?

its needed for armor crafting.

there are a few items that can be crafted
http://www27.atwiki.jp/nine_lives/pages/35.html

Thanks for the answers. I have been out looking for those things but didn't find any so far. But I did find quite few mountain flowers ^^ I guess I'd have to see a pic of how it looks on the ground. So does anyone have or can post a picture of a Sandman Flower on the ground?

@NoName if you see something with a slight blue tone on the ground click it, might be a mountain flower.

I just found my first sandman flower, and it was in a place which seems like it had been placed there deliberately, so perhaps you will have luck trying there:

On the Continental Highland map there is a road to the top of a mountain in the upper right corner (B8 on the map). From the road, you can jump/glide down to a ledge below, which is the only way to access it. There is a hollow tree on that ledge, which you can walk into, and my sandman flower was in there.

I found another one (I am on the hunt).

Here are some images of how it looks on the ground. It is pretty hard to see, especially from the back: http://i.imgur.com/r8TIcNs.png