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Ornamental Grasses Demystified

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Having trouble choosing the perfect ornamental grass for your garden design?

Choosing the perfect ornamental grasses for your garden can be challenging for a number of reasons. In fact, while some plants may have the word grass in their name, they aren’t actually grasses.  Instead, they may be sedges, rushes, lilies,or any number of other non-grass plants. And, while there’s a grass or grass-like plant to fit just about any environmental garden challenge, determining the right one for your spot may be overwhelming.

In this article, we’ll look at several plants with grassy straps to help you understand what kind of ornamental grass you’re growing. And we’ll look at ways to help maintain your grassy plants beautifully and easily.

ornamental Black Mondo grass

First, that ornamental grass you love may not actually be a grass!

Often the plants we refer to as an ornamental grass are actually something very different. For instance, Black mondo grass is actually more closely related to asparagus than it is to grass!

While mondo “grass” has the fun texture of an ornamental grass, this Ophiopogon planiscapus (‘Nigrescens’ if you want the black version) is more a scrappy lily than a grass. Still, this little plant is a great grass-like garden design selection. That’s because of its unique black coloration and sweet little purplish flowers. Plus, it spreads slowly in the garden. And, it tends to play nicely with other plants. And it performs nicely in both sun and shade. Too, it’s evergreen.

We like to pair this ornamental grass (a-hem, lily) with ferns, Japanese maples, bleeding hearts, and even a true grass that I’ll cover later in this article.

In the world of grasses and grass-like plants, there’s much to choose from.

Some ornamental grasses and grass-lookalikes are evergreen. And many of both put on showy flowers.

Some grasses need deep shade. Yet others want hot, dry sunlight.

Many grass-like plants like it soggy — seasonally or always. However, other grasses will rot in wet.

Too, many grasses can be problematic, even if they are beautiful and sold at nurseries or as livestock forage.

So, how to choose the right ornamental grass for you garden design?

First, there’s a great saying if you aren’t sure what exactly a “grass” really is.

Sedges have edges. Rushes are round. Grasses are hollow up from the ground/have elbows down to the ground.

While this old saying may be helpful…It isn’t always going to help you categorize every plant you’re evaluating.

Demystifying a grass-like plant example:

We had to identify a grassy plant growing in our pond. That’s because we thought it might be potentially problematic. So, identifying it was our first step. And to do that we began observing plant details.

First, because this “grass” was living happily in the pond, the plant clearly thrives in very wet conditions. Knowing an affinity for moisture is a commonality for many rushes and sedges, we then directed our research into those types of grass-like plants.

We next observed that the plant appeared to have flat leaves with edges, which usually indicates a sedge.

Too, it didn’t have a showy, lily-like flower. And a flower like that might have suggested it was an iris. Instead, it blooms in clusters at the tips. And those blooms looked more like rush blooms than sedge.

And the plant was relatively short, so it wasn’t likely to end up being a cat tail.

So, what was this plant?

A good plant library can help with detailed plant identification!

Using our resource library, we were able to determine that despite having flat leaves with edges (rhymes with “sedges”), this is indeed the native plant Juncus ensifolius, also known as the sword-leaf rush.

Flora in a pond

Are all rushes created equals & do you want them?

The good news is the mystery plant in our pond is a native plant meant to live in our wetlands. And, much like plain old common rush, these will thrive in a wet garden design.

However, before choosing it, keep in mind that both spread readily from seed pods. And by clumping, spreading roots. Moreover, they can be difficult to dig out if you end up with more than you want!

Junius effusus blooms

Finally, let’s not forget those true ornamental grasses!

True ornamental grasses come in many sizes and forms and environmental preferences. So, there’s one for every garden.

One of our favorite ornamental grasses in Asian-influence gardens and shady spots is Japanese forest grass. While this ornamental grass will take some sun, it performs best when protected from hot, burning late day summer sun. (However, if it can tap into a water source like our pond, it does great in a lot of sun.)

This grass has a soft texture and golden brilliance that’s unbeatable.

We like to pair it with the aforementioned black mondo grass, astilbe, ferns, and hellebores to great effect!

Japanese forest grass & astilbe

But, be forewarned: dogs and cats both love to chomp on it, but so far it appears our deer and wild bunnies aren’t interested in it at all!

Some sedges for your grass garden…

Many ornamental sedges are stunny garden additions. Carex is a genus we particularly adore. In fact, we like to pair Carex testacea (orange sedge) with peonies!

Learn more about gardening with Carex now.

2 comments on “Ornamental Grasses Demystified

  1. Garden Mentors on


    Thanks for writing in. Can you provide more information about this plant? The common name you’ve shared sounds lovely, but it isn’t enough for us to help us help you.

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