Ornamental grass too big

I love the look of ornamental grasses, especially in late summer and into fall when the plumes develop. When the sun hits them the right way they’re glorious!

However, most ornamental grasses with lovely plumes are quite large. My garden is small. This means that the Miscanthus sinensis ‘Morning Light’ growing in my front yard has to be tied back, or it will swallow the rest of my garden (and make life difficult for the letter carrier who has to get into my mailbox every day.) This is the ‘before’ picture:

This is really how big grasses are supposed to look–wild and loose and gorgeous. My goal is to tie them back in a way that retains this look, as much as possible. If you put a big stick in the ground and then grab a rope and cinch it in tight like a too tight belt on someone’s waist you ruin the look of the grasses. Sure, the plumes will still sway in the breeze a little, but the overall look is lost.

How To Tie Up Grasses

My first step is to place three or four tall pieces of bamboo around the perimeter of the grasses–this will give a more natural look than using just one stick.

Next, I take a long piece of garden twine and wrap it around the grass just below where the blades of grass naturally bend over, taking care to work the twine under the flopping over parts of the grass. My focus is on tying up is the stalk and Ieaving the looser parts draping over the twine. I am also careful not to cinch the twine any tighter than I absolutely need too–I’m trying to provide a structure within which the grass can still move, not tie it up so tight it’s completely immobile.

The photo on the left shows what it looks like when I’ve first tied the twine around the stakes. The photo on the right was taken after I worked the bamboo stake back into the grasses–I just shook everything together for a few seconds until the stake was more integrated into the stalks. It’s a small thing but it makes the stake less obvious.

Next, I trim the parts of the stake that are sticking up into the plumes. In the following photos you’ll see what a difference that makes:

And this is the end result:

Note: In order to have you see what I was doing, I used natural coloured bamboo and twine, and it looks ok. But to really make the stakes and twine disappear I would have used use green coloured bamboo sticks or stakes and green twine*.

If I had a big garden I would definitely leave the grasses loose. But if you, like me, need to restrain your grasses, I hope this post has given you some idea of how to do it as unobtrusively as possible.

Gardeners with small spaces can grow big plants, we just have to get really good at tying them up nicely!

*Disclosure: some of the links on this page are affiliate links, meaning, at no additional cost to you, I will earn a commission if you click through and make a purchase.

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How to Keep Ornamental Grasses From Getting Too Big

native grasses image by Lucy Cherniak from Fotolia.com

Ornamental grasses dot the landscape of homes and businesses as a versatile ornamental plant. The simplicity of ornamental grasses allows for minimal upkeep and a stunning foliage display. Ornamental grasses grow quite large if left unchecked. This excessive growth causes problems of encroachment on other plants and dead spots inside the grass clump. Addressing these problems limits plant size to keep ornamental grasses from getting too big.

Protect your arms and legs from sharp grass blades with appropriate clothing. Some varieties of ornamental grasses such as miscanthus and pampas have razor sharp edges. Wear protective gloves and eye wear when using engine-powered trimming tools.

Tie a length of twine around the grass bunch at a height 12 inches above the soil level. Place another length of twine 2 feet above the first rope to secure the upper grass blades. Containing the plant within twine makes pruning easier and more uniform.

Use pruning loppers, hedge clippers or a chainsaw to lop off the dead growth 6 inches from the garden surface. Use gloves to pick out dead foliage buried in the center of the plant. Larger ornamental grass clumps often feature a dead center that indicates the need for division.

Dig around the grass clump to a depth of 6 to 8 inches to allow free root growth. Remove the entire clump from the ground and tip it sideways. Place the shovel blade in the center of the plant and press down firmly to slice the clump in half. Continue dividing the plant in this manner until each clump reaches a manageable size.

Throw a few handfuls of peat moss or compost into the original planting hole and replace one clump of grass in the initial planting site. Firm the soil, water thoroughly around the plant base, and apply a 2-inch layer of mulch. The plant will rebound and eventually require future division.

Select sites for the remaining clumps of ornamental grass. Cultivate the soil to an 8-inch depth and incorporate organic material. Plant each clump to allow plenty of room for mature ornamental grass size. Fill in around the base of the grass with loose soil, water deeply, and add mulch to conserve water.

Help for the Home Gardener from the Help Desk of the
UC Master Gardener Program of Contra Costa County
Client’s Request: I have a very large Purple Fountain Grass plant. I’d like to thin out the plant and cut back the outer “stalks” that keep falling down, generally to “tidy it up”. How large can it grow and what care should I be giving it? Also, I have some nearby blue fescue with reddish brown stalks that I think should be “blue”. Do you think the Purple Fountain Grass might be causing this? Finally, as I’ve previously mentioned, I’m thinking about thinning and/or transplanting the Fountain Grass, when and how should I do that?
Purple Fountain Grass
courtesy: calgaryhort.com MGCC’s Help Desk Response: Thank you for your inquiry to the UC Master Gardeners Program Help Desk with your questions about purple fountain grass.
Purple Fountain Grass (Pennisetum, setaceum) is a perennial plant in Sunset Zones 8-24 (USDA zones 9 or higher) but in colder areas with heavy frost, it is usually grown as an annual. It is native to South Africa, southwestern Asia, and the Arabian peninsula. It is classified as a warm season grass, which is important to know when wanting to prune or divide the plant. It also tends to die back in the winter. It grows best in full sun, in well-draining soil, and is moderately drought tolerant. It can grow in poor soil with little care but will flourish with a little more water and fertilization. As you are aware, it can grow to about 5 feet tall and wide. It is very showy especially in the fall and offers a lovely contrast when planted with other plantings.
Answering your first question on how to thin out the plant and what to do with the falling outer “stalks” (flowers) –the best time to prune fountain grass is late winter or early spring–but be sure to prune before the grass begins to re-grow. Also avoid pruning in the fall before the plant has had time to go dormant.
It is also recommended that you wear gloves and long sleeves as grasses can be sharp and cause itching. Use sharp pruners or hedge clippers. You may need to re-sharpen them as grasses dull cutting blades. Grab the plant and tie a string or tape around it and cut straight across the plant 4-6 inches from the base. Using your hands or a tool, comb through the remaining plant to remove dead grass. If you wish to thin the plant, make small cuttings inside of the plant in several areas. The remaining grass stalks will “disappear” when the plant re-grows and will provide some support to the flowers and blades. This is an arching type of grass so some flowers will fall around the periphery of the plant and you can trim these away but again leave 4-6 inches of the blades. Here is a link to a UC article about pruning ornamental grasses: http://sonomamg.ucanr.edu/2010_Feature_Articles/Pruning_Ornamental_Grasses/Your second question was about the blue fescue with reddish brown stalks and whether or not the fountain grass could be causing this to happen. I could find no information in my research about fountain grass causing this problem. Browning of grass may be due to excessive watering or fertilization or the plant being root bound or excessive sunburn. It may also be the result of the fountain grass shading the blue fescue. Pruning away the brown grass is suggested as well as pruning the fountain grass so it is not shading the fescue. If the discoloration is due to a rust problem, here is an article that tells you how to manage this disease: http://ipm.ucanr.edu/PMG/r785101611.html.
Your third question about transplanting a fountain grass clump and thinning out the plant: you will want to dig up the root ball. You can best transplant and/or divide up the clump in the fall before dormancy or in the spring when the plant is beginning to re-grow. Here is a link which will give you more information: .
I hope I have answered your questions and the links are helpful to you. Let us know if you have any further questions and we hope you are successful with transplanting these beautiful grasses.

Help Desk of the UC Master Gardener Program of Contra Costa County (EKP)


Most of us know what to do with our big grasses that go dormant each winter: Grab a bungee cord, tie the grass up, and use an electric hedge trimmer to buzz the column of foliage to the ground. But what about those tricky grasses that are evergreen or ones that have a ground-hugging habit? When and how do you prune those garden staples that don’t fit neatly into the “large and goes dormant” category?

If you are hesitant to treat your sedge the same as your maiden grass, it’s for good reason. Unconventional grassy plants can’t be trimmed using generalized pruning rules. They require special timing and techniques on your part to look their best. Start by figuring out which category your grasses fall under: evergreen or goes dormant, large or small. This allows you to select the best pruning method, even if you are not sure of the exact varieties you have.

Small and goes dormant

Photo: Before and after pruning Japanese forest grass

When: Yearly, late fall to mid-spring

How: If you like to prune, these short, spreading grasses are satisfying to tackle. Though you can prune any time after they go brown, hold off on cutting these grasses back as long as possible. Even brown, they provide winter interest and act as sculptural sentinels when covered in snow. If you clean up too quickly, you miss a lot of winter beauty. Birds also love to pack and scratch at the seeds in late winter when food is harder to come by.

Depending on your weather though, at a certain point these grasses will start to crumple and look thoroughly messy. When that time comes, use hedging shears to cut these grasses back to a height of 3 inches for the smallest selections – those that are under 3 feet tall, and to 6 inches for taller varieties – those that are over 3 feet tall. If you cut too low, you could be in danger of cutting into the crown of the plant. Moisture then tends to settle into the crowns and rots them out.

While some of these grasses have obvious growth points at the base and can be cut a little lower, others form rounded clumps – and it’s not always clear when you are in danger of cutting into the body of the crown. It’s good to leave a couple inches of leeway and not cut directly next to the growth points so that dew or frost settles a couple inches away from the crown. When I cut too close to the crown, I usually lose a few clumps throughout the plant and need to pull out the rotten bits a couple of months into the season. Pruning should be done every year to give the new foliage a clean slate from which to shine.

Large and goes dormant

What: Maiden grass (Miscanthus), feather reed grass (Calamagrostis), Giant pheasant’s tail grass (Stipa gigantea)

Photo: Before, during, and after pruning Miscanthus

While pruning large grasses that go dormant is a similar process to pruning small ones, there’s something about having a huge mass of foliage towering over your head that makes it seem like a more intimidating task. Plus, bigger grasses can have sharp leaf blades, so if you prune without preparing you can get dozens of tiny stinging cuts on your face and arms.

When: Yearly, late fall to mid-spring Just like with small dormant grasses, it’s best to hold off on pruning as long as possible to preserve the winter interest and to provide food for birds. You can prune anytime after the plants go fully brown, as long as you do so before they start growing again in spring (you don’t want to nip the fresh new growth tips). The grasses themselves will give you your cue. Maiden grasses start shedding soon after the new year, so as soon as you notice them making a mess, it’s time to prune.

How: Even if you choose a sunny day to prune, wear a long-sleeved shirt and gloves so the blades of grass don’t cut your skin. Start by wrapping a piece of rope around the outside of the grass and tie it into a tight column of foliage. This way, the grass will stay bundled as you prune and not explode into pieces everywhere. Once your grass is tied up, use handheld or powered hedging shears to cut the entire grass to about 10 inches tall. If you’re using powered hedging shears, it’s helpful to have a friend hold up the grass so it doesn’t fall on you as you cut. Just be careful not to trim anyone’s ankles!

Though small grasses are easy to clean up, big grasses make a big mess. Plan to put down a fresh layer of mulch after you’re done pruning. This covers any tiny bits of grass that won’t rake up. (More on pruning Miscanthus here and here.)

Small and stays evergreen

Top: Getting the brown blades out of blue oat grass Bottom: Mexican feather grass before, a month after, and three months after pruning

These little charmers are some of the easiest plants to tuck into your garden, because they fit almost anywhere, have year-round good looks, and need little care. Yet even the most easy-going of grasses need periodic attention to perform their best.

When: any time for cleanup, early to mid-spring for rejuvenation

How: By the end of the growing season, brown foliage can pile up inside these plants and give them an unkempt appearance. Luckily, there’s an easy fix to clean them up: just put on some rubber gloves (cheap dishwashing gloves work great) and run your fingers through the grass as though you were combing its hair. The spent foliage clings to the rubber and comes out in easy clumps. You may not be able to clean out all the spent blades, but removing some will trigger the grass to refresh itself.

Sometimes, of course, a stronger solution is needed. If painters have trampled on your evergreen grasses or if wind or winter cold have damaged even the freshest leaves, it may be time to go in for the big chop. In early to mid-spring, use your hand pruners or hedging shears to reduce the height of your grasses by two-thirds. While this leaves your grasses looking like awkward hedgehogs, these grasses bounce back fairly quickly and usually look good again in 2 to 3 months.

Cutting these grasses back too much will allow moisture to gather on their crowns, which can cause rot. When I’ve experimented with cutting back more than two thirds, portions of the grass died a soggy death. If you’re overly zealous with the pruners, you could also cut into the growth points on the crowns without knowing it – especially on sedges, which can form a mounded crown.

Rejuvenation pruning shouldn’t be done more than every 2 to 3 years because small evergreen grasses have slightly less vigor than grasses that go dormant. When you cut off all that foliage, the plant is losing energy stored in its leaves, so it ends up with less energy to put into producing new growth. I like to give the grasses time to recover before subjecting them again to a stern pruning. The exception is Mexican feather grass, which can be pruned back hard any time its foliage clumps into unsightly dreadlocks:

Large and stays evergreen

What: Flax (Phormium), Cordyline (Cordyline), Yucca (Yucca)

Photo: Before, during and after pruning a Phormium/ flax

Although technically not “grasses”, these large, spiky plants stand as focal points in the landscape, drawing attention with their bold colors in dramatic shapes. This makes it all the more important to prune right, because a poor pruning job will be noticed by everyone. Unlike with large deciduous grasses which are whacked back almost to the ground, subtlety is key when pruning large evergreen “grasses”. There are many reasons to prune these plants, ranging from the removal of dead flowers and ratty leaves, to keeping plants in scale with their surroundings. With brightly colored flax, there’s another reason to prune: The new growth is more brilliantly-colored.

When: Anytime for cleanup and resizing; mid-spring for rejuvenation

How: When pruning to freshen up foliage, I simply select the oldest or most damaged leaves and cut them out at the base. This might seem like a time-consuming task, but once you get into a rhythm, it goes pretty quickly. Use the same technique to prune for size. Grasp the tallest leaves, and one by one, cut them out as far down towards the base of the plant as possible. When pruning for size, move around the plant as you go, removing up to two thirds of the leaves, which is the point at which the pruning becomes obvious.

Sometimes, however, selective pruning just doesn’t cut it. If your plant is overgrown, has significant winter damage, or must be cut to make room for construction, you can prune severely in mid-spring. Use hedging shears to cut off all the foliage at the base. You’ll end up with a mound about 1 foot tall. While cutting off all the foliage is not an ideal approach, these varieties grow back quickly and look good again in about four months. They do, however, have an awkward phase during their regrowth: When the blades start to regrow, some will look damaged and have clipped tips, so you’ll need to selectively prune again to remove those. This allows the fresh new growth to shine.

Over time, some varieties of Yucca and Cordyline grow quite tall and develop a long trunk. If you don’t want yours to look like a tree from a Dr. Seuss story book, cut the plant midway down the stem; it should pre-sprout from just under the cut point. In areas where these plants are marginally hardy, however, cut the trunk back by only one third. Sometimes that stem will re-sprout, but occasionally, the plant will sprout up from the base, instead. One last caveat: Be sure to wear eye protection any time you are pruning spiky grass-like plants. When you are focusing on removing leaves at the base, it’s easy to lean down and get stabbed in the eyeball with a sharp leaf tip. That’s a definite pruning “don’t”.

(Article originally appeared in Fine Gardening Magazine)

Preventing Flopping Grass: Causes Of Ornamental Grasses Falling Over

Whether you want to make a subtle statement or a big impact, ornamental grasses can be just the right design detail for your landscaping. Most of these grasses need very little care and thrive on neglect, so they’re perfect for even novice gardeners to grow. One of the few problems you may have with an ornamental grass plant, however, is the stems falling over, otherwise known as lodging of ornamental grasses.

Causes of Ornamental Grasses Falling Over

Preventing flopping grass in the garden is easier once you understand why ornamental grass falls over. Most of the problems associated with flopping ornamental grass is because of gardeners taking too much care of the plants, not too little.

The most common cause of ornamental grasses falling over is too much nitrogen in the soil. If you have a habit of fertilizing your ornamental plants on a regular basis, you’ll be causing the problem you’re trying to avoid. Give these plants one application of 10-10-10 fertilizer first thing in the spring just as the grass blades begin to sprout. Avoid any more fertilizer for the rest of the year.

Another reason your ornamental grass may flop over is that it has grown too big. These plants benefit from being divided every three or four years. Once they grow to an overly large size, the sheer weight of the mass of grass blades can cause the entire plant to bend down and fall over. Divide the plants in spring before any fresh shoots appear and plant each new grass clump far enough away so that it doesn’t shade its neighbors.

How to Fix Falling Ornamental Grass

So how do you fix falling ornamental grass once it’s happened? If the damage has been done and your ornamental grass has fallen over, you can give it a quick fix until the stems are strong enough to hold themselves up again.

Simply pound a stake or length of rebar into the ground in the very center of the grass clump. Wrap a strand of garden twine that matches the grass around the entire clump, about halfway up the stalks. Tie the twine loosely enough so that the grass can move naturally, but tightly enough so that the strands all stand up in one vertical clump.

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