Native Combinations: Late Summer Glory

Pink Muhly Grass (Muhlenbergia capillaris) has seduced garden designers for the last decade.  Its haze of hot pink inflorescences set the late summer garden ablaze.   But unlike other ornamental grasses, it is a surprisingly tricky plant to design with.  Muhly Grass does not offer the same early season mass and volume that Switchgrass and Fountain Grass provide.  In fact, through most of the summer, it sits low and wiry—barely substantial enough to cover the mulch.  I planted a large mass of 120 plants beside a path in a southern garden I designed.  The result was rather disappointing.  Until August, it looked rather weedy and insubstantial.  Once it bloomed, the effect was glorious.

Muhly Grass in early summer is rather uninspired

So to avoid Muhly Grass’s spring and summer doldrums, use it in combination with other plants.  I now use it almost like a bulb or other ephemeral.  Plant it along the edge of the border next to other fuller edge perennials.  Or drop it inside the front of the border and let it disappear in other perennials until it blooms.  One of my favorite combinations I saw at the U.S. Botanic Garden’s National Garden.  They combined Pink Muhly Grass with a dwarf cultivar of the native Swamp Sunflower. 

Helianthus angustifolius‘Low Down’ is a fantastic cultivar of a truly underused native.  Low Down Sunflower offers narrow, black-green foliage at a height that is more suited to the average garden.  While the straight species reach a sprawling seven feet tall, ‘Low Down’ stays between 2-3 feet high.  The plant is literally blanketed in flowers from late summer well into the fall.  The blooms are great for cut flowers.  And while it is native to moist soils, this plant does well is average garden soils.

Low Down Sunflower is perfect in combination with Pink Muhly Grass.  Both share light, narrow foliage, but the Sunflower adds mass and volume in the spring and summer—when Muhly Grass is rather boring.  And in late summer, each plant explodes in bloom.  The Muhly Grass covers the dense Sunflowers in a pink mist.  Each plant is a show-stopper, but the combination is truly captivating.  Both plants do extremely well in the hot and humid southeast and midwest--areas that often challenge perennial gardens.

Helianthus a. 'Low Down' combined with Muhlenbergia capillaris at the U.S. Botanic Garden

When I hear someone say that natives are not quite as showy as exotic plants, this combination often comes to mind.  Our imaginations are the only limit to the potential of native plants.