Brian Busse, the president of Applied Imagination, holds an item created for the U.S. Botanic Garden's "Who Lives Here?" show.

At the U.S. Botanic Garden, each holiday season brings a chance to see an alternative D.C., in which the White House and the Capitol are made of twigs and pinecones. The garden’s annual winter display — tiny buildings made of plant materials and circled by toy trains — is the work of Applied Imagination, a Kentucky-based crew of artists, botanical architects and landscape designers. Brian Busse, the firm’s president, offers a peek behind the scenes of this year’s “Season’s Greenings” show, which also includes “Who Lives Here?,” an exhibit that features presidential and animal abodes in miniscule detail.

How far in advance did you plan this show?
It tends to be about 10 months in advance. About nine of our artists worked full time over the past eight months on “Who Lives Here?”

Any tips for the best viewing?
I really encourage people to actually lean in and take a closer look at each building. They’ll discover a plethora of material that makes up each building. The Capitol is made of dried roots, bamboo, beechnuts, pear pods, pinecones, acorn caps and wild grape vine tendrils.

 “Get as close as you can”? You don’t hear that very often at museums.
Lean a little over the rope and you’ll realize that there are details you could have easily passed by. A doorknob can be a peppercorn seed.

I bet your family had the best gingerbread house on the block when you were a kid.
We did. We used to have a holiday art show in our house in Cincinnati, Ohio. We would bring in over 35 artists, and they would display their art. Out in the front yard, we would set up model trains for all the children in the neighborhood.

You’re still playing with trains as an adult! Are you ever surprised you didn’t grow out of it?
No. It’s been fun from the day I started.

U.S. Botanic Garden, 100 Maryland Ave., SW; through Jan. 2, free; 202-225-8333. (Smithsonian)