Probably enough during that journey he made studies of the cypress, stone-pine, date-palm, olive, orange, and palmetto, which occur in his pictures.
They grow in the south of Spain and other Mediterranean regions, but not in the cold north where Hubert spent most of his days.
It is difficult at first to realize what an innovation it was for Hubert van Eyck to paint such a landscape.

In the Richard II.

diptych there is just a suggestion of brown earth for the saints to stand upon, but the rest of the background is of gold, as was the common practice at the time.

The great innovator, Giotto, in some of his pictures had attempted to paint landscape backgrounds.

In his fresco of St.Francis preaching to the birds there is a tree for them to perch on, but it seems more like a garden vegetable than a tree.