There just aren’t that many red and orange flowers native to the Maryland Piedmont, and I’ve only seen three of them. That makes me a little sad.

Campsis radicans (trumpet creeper; Bignoniaceae)

This herald of summer, with four-inch flowers on vines up to forty feet long, starts blooming in mid or late June and can go through early August. Look for it climbing up and along boulders and tree snags in open areas.

Lobelia cardinalis (cardinal flower; Campanulaceae)

This plant is a real showstopper, with clusters of lurid red flowers atop stems up to four feet tall. Look for it growing in very wet places, like right on river banks. It blooms from mid August into September.

Impatiens capensis (jewelweed; Balsaminaceae)

Look for the rather large yet wispy plants growing in wet places, like small seasonal streams. They bloom on and off from late spring until late summer. 

Here are links to some of the other red and orange blooming species in this area:
Asclepias tuberosa (butterfly weed)  Beloved of gardeners everywhere. Great pollinator plant.
Lonicera sempervirens (trumpet honeysuckle) There are just a few records of this in the Piedmont; mostly it’s a plant of the Coastal Plain.
Aquilegia canadensis (wild columbine)
Lilium superbum (Turk’s cap lily)