Tuesday, June 14, 2011

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.  

6 comments:

  1. Looks like a beautiful combination. How does the Helianthus angustifolius look when it's dead? Does it have a lasting, attractive structure, or does it say "cut me down"?

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  2. James,

    It looks pretty wonderful through late November and December when it still holds some of its leaves. But after that it's pretty sticky. Not wonderful, but not bad.

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  3. Great post....and something I've been pondering this year as well. I planted some Pink Muhly a few seasons ago, and you're right, the fall color is stunning...almost unbelievable coming from a plant that is rather dull-looking most of the year! I'll have to re-think the area...this was good inspiration!

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  4. We've used your native Gulf Muhley / Regal Mist Grass for a while here. I like it in mass w/ wildflowers like you show, as well as in swaths among evergreens, esp. spiky ones. A mass of it near the trailhead where I mtn bike is along a hot west wall, with some drip irrigation, and it even takes that!

    Since we can't buy (or specify) our native pink-in-fall muhley in the desert SW - it didn't sell, as our hort gatekeepers did not promote it - M. capillaris has to do!

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  5. Very nice combo although the Muhlenbergia isn't hardy enough here (I think). I also like Molinia 'Skyracer' for a similar but taller transparency/curtain effect. I have used this with taller perennials and has worked well.
    Heather

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  6. Thanks for this post -- and for the one on cool and warm season grasses. I have been looking for good advice on which grasses to use in my small garden. Unfortunately, too many sites on the web only show photos of closeups of the blooms. Nurseries seem to photograph their selections only in the fields or plunked down by the edge of their parking lots. It's helpful to see good pix of grasses in a garden setting and to see the whole plant. - Cindy

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