Additionally, you'll want to consider the other plant's mature size, growth habit, and root structure to prevent competition ... Plants like lobelias, especially cardinal flower (Lobelia cardinalis), ...

Funk suggests considering these plants: Red flowers. Cardinal flower (Lobelia cardinalis) if planting in the shade. This July-October-blooming flower prefers shade and moist areas. Royal catchfly ...

"Black-eyed Susans are hardy, easy to grow, and excellent for attracting pollinators," says Root ... flower normally, but are prone to flopping, thus requiring support." Consider the Cardinal ...