From Reporter plugin version 2.0.1, a new feature was added - Portrait and Landscape Orientation. It is a great new option that allows you to choose the appropriate orientation of the Reporter template that will best fit your needs.
To access the feature, please go to Administration (on top) - Plugins - Reporter - Report Templates. And here edit some of the reports in the list.
Afterward, please choose some of the 2 available options for Orientation:
And then, the report will look like this: