Planting for pollinators is a great idea but you need to have something in bloom from April to October. Plants for the spring, summer and fall are easy to find but there is kind of a lull in blooming in mid-June to July. That is where the Penstemons come in.  They flower during that time period. They are host plants for the Baltimore Checkerspot butterfly. The tubular flowers attract humming birds, bees, butterflies and other pollinators. Very Showy plant to add later spring color to your garden. 
 
Hairy Beardtongue is a versatile plant with lovely pink and white tubular shaped flowers. The green leaves are lance shaped, The plant forms clumps but will self-sow. Hairy Beardtongue grows from about 1 to 2 feet high. It grows well in moist soils will tolerate drier soils too and will take sun or partial shade. It is a wonderful rock garden plant and will work great in rain gardens. This plant is deer resistant. 
 
Good companion plants will depend where you are planting it. In a rain garden you can use it with White Turtlehead, Asters, Palm Sedge, Monardas, Lobelias, Golden Alexanders, Little Blue Stem Grass and others. In a drier area such as a rock garden you can plant in with Wild Columbine, Pearly Everlasting, Black Eyed Susan, Sedum and others.