Wildflower Wednesday: Chasmanthium latifolium, A Year Round Beauty

I love native grasses and there aren't nearly enough in my garden. Shallow soil and shady conditions limit them at Clay and Limestone, but, Chasmanthium latifolium (River Oats) is deliriously happy here and it makes a gorgeous big impression....And I do mean a big impression.

I think it's important to tell the truth about plants I showcase and the truth is that while I love River Oats I need to issue a word of caution--This grass spreads through rhizomes and can be aggressive. It will also reseed itself. In fact it has seeded itself vigorously around my sunnier border and taken over spots once inhabited by other sweet native wildflowers! I don't blame the plant, that's its nature. I hold myself completely responsible that it has run roughshod over other plants.  

The first few years in the garden

When I was young and eager to have a wildlife friendly garden I chose River Oats because it had year round beauty and good wildlife value. It was easy to grow and tolerant of many different light and soil conditions. I loved that it was a larval host plant for butterflies as well as a food source for small mammals and birds. Later on I learned that it provided shelter for small mammals and was an important plant for lightening bugs.*

It was in the ground and well established when a gardening friend visited and said this to me when she noticed the large clump of river oats: "Oh my, why did you plant that?"  She knew what many of us learn from experience, that river oats can be a bit thuggish in some gardens. That's what I found out...Each and everyone of those spikelets can make a new plant in moist soil. It can in dry soil, too!  

But let's talk about its wonderful characteristics!  

River oats is a cool season clumping grass that emerges in spring with bright green arching bamboo like foliage before most native grasses.

April green leaves with Phlox pilosa

It's especially lovely in early spring as it mingles with early spring wildflowers.

  

Leander Bruce photo

 The flat nodding green seed heads that resemble oats emerge with foliage. The spike like flower heads sway gently in the slightest breeze. 

It always strikes me as too soon when the flowers ripen into seeds. But look how lovely the yellow gold looks with Physostegia virginiana. How ironic or maybe appropriate that two of the most disobedient plants in my garden dance so well together!

Here are two of my favorite fall photos through the years.

It seeded itself among the witch hazels, Hydrangea arborescens and a long gone Japanese Maple tree.

a lovely couple 

 By early winter the leaves are a gorgeous yellow and the seedheads are bronzing. Full on winter they're still beautiful.

Yellowing up on its way to bronze winter color

Since I garden for wildlife I don't clean up my garden in winter. This means that I let the River oats and the stems of wildflowers stand all winter. This allows insects that over winter in stems a safe haven and food for birds who forage the seed heads. River oats foliage insulates and protects the plant, adds winter interest and its thick, clumping habit offers essential cover and nesting materials for birds and small mammals.

 If you're really lucky you get to see them in snow. 

 

Chasmanthium latifolium has more pluses than minuses, but, plant it only if you don't mind a plant that vigorously reseeds or if you have a space in your garden where it can make its big statement! I am a huge fan of colonizing, rough and tumble, take care of themselves native plants and this is definitely one of them.

wind pollinated

I've seen it growing in rich woodlands adjacent to cedar glades where it it co-mingles with Hypericum frondosum, Rhus aromatica and sedges.  It can also be found naturally growing in rich woodlands and  stream beds slopes. It's perfect for stabilizing a stream bank or a slope that's eroding. If you've ever tried struggled to dig a clump to divide or transplant you know that its fibrous and deep root system would hold back the steepest slope!

I will be doing some editing this spring and summer! Wish me luck!xoxogail

 

 

The Particulars

Common Name: Indian Wood Oats, Inland Sea Oats, Northern Sea Oats, River Oats, Wild Oats, Wood-oat 

Type: Ornamental grass 

Family: Poaceae 

Native Range: Eastern United States, northern Mexico 

Zone: 3 to 8 

Height: 2.00 to 5.00 feet 

Spread: 1.00 to 2.50 feet 

Bloom Time: August to September 

Bloom Description: Green 

Sun: Full sun to part shade 

Water: Medium to wet 

Maintenance: Low, if planted in the right place!

Suggested Use: Use in naturalized areas, along streams or edges of water gardens. Watch its placement especially in smaller gardens as may spread aggressively by rhizomes and seeds. 

Comments: Showy flowers look like oats. A good cut flower in arrangements. Great winter interest. Highly resistant to deer.

Wildlife value: Larval host plant for Northern Pearly-Eye (Lethe anthedon) caterpillars.  Also a larval host plant to several skipper butterflies. Small mammals and birds are attracted to the seeds. Shelter to small mammals in winter.

*Special note: River oats  are an excellent native grass for creating a firefly-friendly habitat, providing necessary shade, moisture retention, and structural support for mating. These ornamental grasses offer protective cover for larvae and resting spots for adult fireflies, particularly in shady or riparian areas.

 

 

 Welcome to Clay and Limestone's Wildflower Wednesday celebration. On the fourth Wednesday of each month I share information about wildflowers and other native plants. Please join in if you like. You can write a blog post or share your favorite wildflower on social media. Remember, it doesn't matter if they are in bloom or not, and, it doesn't matter if we all share the same plants. It's all about celebrating wildflowers.

Gail Eichelberger is a gardener, Tennessee Naturalist and nature writer in Middle Tennessee. She loves wildflowers and native plants and thoroughly enjoys writing about the ones she grows at Clay and Limestone. She reminds all that the words and images are the property of the author and cannot be used without written permission.