Mykarma, it looks to me like that particular planter was made free form, likely not using a mold - at least if I were making one I'd do it free form, and in the final finishing (carving) stage make the depressions where I wanted them.

Someone here made a smaller & similar version for planting hens and chicks in. You might be able to use construction methods mentioned there, just on a grander scale!

~GC

Here is a link that might be useful: hens & chicks rock

Mykarma, It's a round trough (bowl) and the sides have been worked (wire brush, screw driver, hammer) to look like stone. It's planted with alpine plants and dwarf conifers. Believe they've placed a large rock on top to the right in the back. The plants have just grown over the sides. If you take a look at page 60-61 you'll see how they place the rocks and then the plants over grow and cascade down the sides. The one you're looking at probably looks like a stone because it's round.
This could be a tracking job for Rick Harmer.
Rick, Rex Murfitt (co-author of the book) use to live in Victoria, BC don't know if he's still there. I took a class at Delaware Valley College from the other co-author, Joyce Fingerut.
I like this book because there are better details than Sherrie Hunter. I still don't like their ingredients of fibers and liquid acrylics BUT it really does explain how to make troughs. There's also a whole section on what plants they use. These people are into alpine plants. Believe Joyce was the President of the North American Rock Garden Society. Billie