Gardens are flowers, trees, shrubs, pools, fruits, vegetables, paths, birds and weeds.
Sometimes, they are buildings, too.
Consider old-fashioned summerhouses, gazebos, trellises, arbors, lattices, porticos, pergolas and porches.
Trelliswork is an old garden art that began as an openwork or fence to support climbing plants. It sometimes was used as the framework of an arbor.
All of this conjures up a vision of Victorian gardens with climbing roses and morning glories and lemonade in the pergola.