There are many mounding plants, but they need to be interspersed in a garden with some vertical accents.
Summer bulbs are labor intensive, as they have to be dug and stored each fall; however, they add immeasurably to the diversity of the summer garden.
All bindweeds have arrow shaped leaves on long stems, and their underground rhizomes are hard to dig up.
Aegopodium, a.k.a. Goutweed, grows vigorously in temperate zones. Nothing except an extremely hot dry summer ever slows it down.
Corydalis has delicate lacy-looking foliage and racemes of spurred flowers in the spring.
Ninety percent of the bulbs in home flower gardens belong to just 6 genera: Narcissus, Tulipa, Hyacinthus, Iris, Lilium and Gladiola.
In my Indiana garden in midsummer, the beardless Japanese iris bloom with great abandon and considerable style.
Many white flowers bloom in May, but the tiarella is one of the only ones to bloom so prettily in the shade.
There are about 40 Eupatarium species of native North American wildflowers available and they like room to romp and form large clumps.