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Caring for Ornamental Grasses in Seattle

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Caring for Ornamental Grasses Made Easier!

Autumn is probably my favorite time of year to really enjoy & care for ornamental grasses. And, by grasses I don’t mean lawn. Instead, I do mean ornamental grasses and grass-like plants such as sedges and rushes. Plants like blood grass are brilliant red and showy at this time. Seed heads on Miscanthus are shining and flowing in the breeze (and frost). And cute little tufts on bunny grasses hop along at the edges of borders. As well, hairy carex shimmers, promising interest into the winter ahead.

'The Blues true grass' Schizachyrium with Lambs Ear

Or, to clarify, it will promise to be interesting if it’s well cared for.

Too often, all of these plants are treated the same by unknowning humans with scissoring tools in hand. And not all of these plants do well when trimmed the same way. In fact, this can cause permanent damage. So to help you wade your way through your grasses, following are some general guidelines for caring for ornamental grasses and grass-like plants. Of course,there may be exceptions to the rule, but these tips should help you avoid the big mistakes!

First, How to Care for True Ornamental Grasses:

True grasses have “elbows” or “joints” where the leaves run down the stems to the ground. And these plant may be clumpers or spreaders.  As well, most will do well when you them cut down at the end of the season. But, what you define as “the end of the season” is your call.

If you enjoy looking at seed heads swaying in the autumn sunlight, then you might wait until after a frost or until mid-winter to cut the plants down. However, if you are concerned about the plants spreading in the garden after forming and spreading their seed all winter, then you might cut them down earlier.

A Few Tricks for Trimming Different True Grass Categories:

Miscanthus Seed Head Adorned with First Snow

Grasses like blood grass are easy to snip at individually to remove. Clumps of bunny grass are tight and with a sheet underneath are easy to shear and then pluck out brown old growth. Tall grasses like Miscanthus are best bundled tightly with string and then cut a few inches above the ground but below the tie. This way the bundle comes away in one bunch. Take care, these plants may have sharp edges.

Next, Let’s Look at Caring for Ornamental Sedges:

Sedges have edges but no elbows. And, they are often mop-like and spreading. Generally, their seed heads aren’t showy. So, they may be called ornamental grasses, but they aren’t really grasses.

Carex testacea intermingling with Euphorbia

Carex testacea intermingling with Euphorbia

These plants do not take kindly to being cut hard. But, some will die back for winter. However, most ornamental Carex is an evergreen plant that should be combed and very lightly trimmed once or twice a year.

I tend to comb mine out in mid-summer and again in fall or winter. And, I’m careful to wear gloves when I work. That way the sharp edges don’t slice my fingers. After I comb out all the dead and stringy growth and remove any dead clumps, I bundle the plant in my hands. And I trim off the dead ends, which should be around 2″ or so of the very tips. Its like giving the plant a little bob haircut.

However, if the plant has been neglected for a long time, the center may begin to rot. In these cases, I dig out the plant to divide it and reinvigorate growth. So, toss the rot. And replant the rest.

Finally, Tips for Caring for Rushes:

Rushes tend to seek out wet areas. And they will readily spread by seed as well as roots. So, to keep them in check, I dig up unwanted seedlings while they are young. That’s because they can be really difficult to remove later. And, in spring, I often cut mature rushes that I want to keep hard. That way they won’t spread seeds. And they’ll have time to bounce back and look nice and evergreen in winter.

Carex flagellifera with Lambs Ear

Carex flagellifera with Lambs Ear

This just skims the surface of ornamental grass care!

There are many, many more grasses to choose from and care for. Some are weedier than others. Some are sharper and harder to care for than others. And, many are just plain wonderful and not to be missed for their fantastic, unique forms, textures and colors they add to to the garden.  If you aren’t sure which kind of grass plant you have or if you have one that isn’t specifically mentioned here, sign up to join our online learning programs so we can help you get past your specific challenges with caring for ornamental grasses. And more!

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