Hi, Ron. The plants you saw were trained into "Standards". You can use this technique on any plant that makes a woody stem. It's tricky to find information on the web, since "standard" is such a common word and using it in a Google search gives all sorts of unrelated hits. Nevertheless, I found a decent site to get you started, and the link is below. Now that you know the term, you can do some more digging on your own. General gardening guides should have some mention of training plants into standards. Books on topiary should also help.

Go wild, and become a garden wizard-artist, yourself!

Here is a link that might be useful: White Flower Farm gardening guide: growing standards

Ah,Calgary Cailin, I, like an inquisitive Alice, followed the white google rabbit and tumbled into the White Farm's website and downloaded this very article..... we are a couple of gregarious googlites pinballed into identical spaces,eh!

A very plain and humdrum name...'standard' for such an amazing process!!!

Thanks.... keep on dodgin' those chinook bullets trying to seduce your floral lovelies into premature coolies of security..... yes, I am the westward scion of southern Albertan sodbusters...lol

Ron