Yard and Garden: Add Autumn Color with Grasses

October 17, 2019, 10:33 am | Richard Jauron, Willy Klein

Little Bluestem Grass by L.A. Faille/stock.adobe.com.AMES, Iowa – Native and ornamental grasses are wonderful for adding multiple seasons of interest in the garden. They add instant texture and form to the garden any time of year whether grouped in clusters or planted singly as focal points. Iowa State University Extension and Outreach horticulturists recommend native and ornamental grasses with good fall color. To have more questions answered, contact Hortline at hortline@iastate.edu or 515-294-3108.

Which ornamental grasses have colorful fall foliage?  

Several native and introduced ornamental grasses have good fall color. Native grasses with colorful fall foliage include big bluestem (Andropogon gerardii), switchgrass (Panicum virgatum), little bluestem (Schizachyrium scoparium), Indian grass (Sorghastrum nutans), and prairie dropseed (Sporobolus heterolepis).  

Purple moor grass (Molinia caerulea subsp. arundinacea), Japanese forest grass (Hakonechloa macra), and Chinese silver grass (Miscanthus sinensis) are introduced grasses with colorful fall foliage.  

Which native grass cultivars have good fall color?  

Many native grass cultivars develop good fall color. Big bluestem (A. gerardii) cultivars ‘Indian Warrior’ and ‘Red October’ have purple and scarlet red fall foliage respectively.  

Switchgrass (P. virgatum) cultivars ‘Cloud Nine,’ ‘Dallas Blues,’ ‘Heavy Metal,’ and ‘Northwind’ have yellow fall foliage.  

Cultivars of little bluestem (S. scoparium) with excellent fall color include ‘Blaze’ (shades of orange, red, and purple), ‘Blue Heaven’ (burgundy red), ‘Carousel’ (copper, orange, and mahogany), ‘Jazz’ (burgundy red or purple), ‘Prairie Blues’ (shades of orange and red), ‘Prairie Munchkin’ (mix of orange and purple), ‘Standing Ovation’ (maroon to purple), and ‘The Blues’ (shades of orange and red).  

In fall, the foliage of Indian grass (S. nutans) cultivars ‘Indian Steel’ and ‘Sioux Blue’ turns yellow, while the foliage of ‘St. Louis’ is orange-red.  

‘Tara’ prairie dropseed (S. heterolepis) develops an orange-red fall color.  

When should I cut back my ornamental grasses?  

Many ornamental grasses provide color, sound and movement to the winter landscape. Because of these winter features, April is the preferred time to cut back ornamental grasses in Iowa. Cut back the grasses to within 2 to 4 inches of the ground with a hand shears, lopping shears, hedge trimmer or small chainsaw.  

When is the best time to dig and divide ornamental grasses?  

Spring is the best time to dig and divide ornamental grasses. Wait until new growth appears at the base of the plants in spring. Digging and dividing well established clumps of grass can be quite challenging and may require the assistance of others. After digging up the clump, divide it into sections with a sharp knife, spade or ax. If the central portion of the clump is dead, cut it out and discard it. Divide the outer ring of the clump into sections and replant.


Photo: Little Bluestem Grass. Photo credit: L.A. Faille/stock.adobe.com


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