Answer: Not many perennials will grow happily in dry shade. The soil beneath your maples is dry because the tree roots will compete with the roots of any flowers you try to grow there. That's why you are successful with impatiens in a planter. There are a few plants that will tolerate - and even thrive - beneath maples:
Hosta plants form a leafy garden dense enough to choke out weeds. If planted in rows, they are impressive enough to serve as borders.
Liriope spicata looks like a grass (its common name is "border grass", or "lilyturf"), even though it's actually a member of the lily family. But liriope also has a spikey flower, ranging in color from white to lavender. In autumn it bears a dark berry.
Foxglove is distinguished by its showy floral display. It is also the tallest of the plants for dry shade.
Stella de Oro Daylily is a true "daylily," in the sense that its individual flowers last only a day. But don't be fooled into thinking that you won't get much of a show out of this perennial. Another bloom will be along shortly to replace yesterday's departed beauty. In fact, its ability to re-bloom over a long period makes Stella de Oro daylily perhaps the most popular of the daylilies. Its popularity is also due to its ability to adapt to a wide range of planting zones and conditions, including dry shade.
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