By: Bonnie L. Grant, Certified Urban Agriculturist
Ornamental grasses provide movement, sound and architectural interest to the garden. Whether they are planted en masse or single specimens, ornamental grasses add elegance and drama to the landscape with ease of care and self-sufficiency. Maiden grass is an excellent example of a landscape grass. Once established, these plants in the Miscanthus family need relatively little attention; however, they will need division once in a while. Dividing maidenhair grass keeps it to a maintainable size, increases the number of these plants and prevents center die-back. Learn when to divide maiden grass and some tips on how to split apart the larger specimens of this species.
Miscanthus is a large family of grasses. There are many varieties of maiden grass in this group, most of which are excellent landscape plants and valued for their dramatic inflorescence and gaily waving foliage. Splitting ornamental grass plants should happen every 3 to 4 years. Can you divide maiden grass? Maiden grass responds favorably to division and will come back better than ever after a season.
The question, “can you divide maiden grass?” has been answered, but now we need to know the when and how of the project. Older Miscanthus can get many feet wide and may grow 5 to 6 feet (1.5 to 1.8 m.) in height. This is a monster of a plant to divide but it is necessary for best plant health.
The best time to divide maiden grass is when it is dormant. Cut back the foliage to 5 inches (12.7 cm.) from the crown first. This will help you get at the base, which needs to be dug up and prevents harm to the root system. Now assemble some tools and a couple of buddies if you are splitting ornamental grass plants that are huge and old.
Neglected old grasses may pose a problem for removal of the root ball. The faint of heart might want to call in a professional crew, while the adventurous might enlist a backhoe or pickup truck. The root ball has to come out for a successful division.
Dig several inches (7-8 cm.) around the crown of the plant in order to capture the edges of the root zone, then dig under the root mass and pull it all out. The root ball may be huge, so slide it onto a tarp for ease of movement. Now the division process occurs.
Smaller plants can be cut with a root saw, while the big ones may require a chainsaw, pry bar or other robust tools. That is why it is good to know how to divide maiden grass when it is young, or you will end up with quite a large project.
Divide the clump into sections of around six inches (15 cm.), retaining roots and crown in each piece. Keep the roots moist and replant each section immediately.
Once the clump is out of the ground, you can also divide the small shoots or tillers with water. Rinse off all the dirt and pull out the individual shoots, including their roots. Each one of these is a potential plant, although it will take longer to establish a large clump of Miscanthus than the bulk division method.
These small plants should be potted up and babied for a few years in a sheltered area or greenhouse before planting in the garden. This method will result in more plants than you can probably use, but the benefit is that the new plants will not transfer disease or weeds to a new area of the garden since the old soil was washed off.
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Read more about Maiden Grass
One of the most rewarding aspects of perennial gardening is the fact that most plants actually increase in size over the years. After a time, some of your perennials are going to benefit from being divided, and in most cases spring is a terrific time to go about this task.
We divide perennials for a number of reasons:
1. Clumps have started to die out in the middle. The classic “doughnut” shape with an empty hole in the center is a sure sign that a perennial clump needs attention.
2. Flowering performance has declined. The clump may have become congested, or the roots old and woody.
3. Soil nutrients have been exhausted around the clump. Signs of this might be stunted growth, yellowish leaves or lack of bloom. Dividing and moving to a new location is a wise idea. Sometimes simply fertilizing the plant will make it smarten up.
4. Perennial weeds have infested the clumps. When this happens, usually the best approach is to dig up the entire clump and divide it, picking out every single piece of weed root that can be found.
5. We want to make more of our favourites. Dividing established clumps can provide plenty of new plants for a new garden bed, or to share with friends and neighbours.
One rule of thumb for division is this: perennials that flower between early spring and mid June are best divided in early fall. Perennials that flower after mid June are best divided in the spring.
This rule is one that many gardeners break with regularity, experiencing relatively few problems. I don’t like to see spring-flowering perennials divided while they are blooming, but doing it immediately afterwards often works just fine. Primroses, for instance, can be dug up and divided into numerous piece in late spring, giving them an entire season to recover before flowering again the following year. Same thing with many of the spring-flowering rock garden plants, such as Rock Cress (Aubrieta), Basket-of-Gold (Aurinia) and Moss Phlox (Phlox subulata).
Summer and fall-flowering perennials have the whole spring and early summer to recover from being divided, and most will give you an excellent flower display the same year. Spring is the very best time for dividing most ornamental grasses, and especially the fall-flowering types such as Maiden Grass (Miscanthus) and Fountain Grass (Pennisetum).
Three plants that I prefer to see divided at other times are Peonies (fall only), Oriental Poppies (in July or August when they are dormant) and true Lilies (mid to late fall). Daylilies (Hemerocallis), on the other hand, can be divided at nearly any time, but spring seems to suit them perfectly.
Traditionally, the time for dividing Bearded Iris is shortly after flowering, in July or early August. But if you have stubborn clumps that refuse to flower, then you might as well go ahead and divide them in the spring, since they likely won’t bloom this year anyhow.
How to Divide
For beginning gardeners, the first time or two you divide perennials you are going to be nervous and unsure of what you’re doing. This is normal! But once you see the results, you’ll start to realize that most often plants will recover quickly and be all the better for the experience. Even seasoned gardens get carried away at times by dividing plants into pieces that are too small, and the results are sometimes mixed — some pieces grow well, some die. We usually still end up with more plants than we started with, so consider it a success.
The basic steps of dividing are simple. Once your plant shows signs of growth in the spring (an inch or two of new shoots is fine), dig up the entire clump. Try to be generous and get as many thick roots as possible. I like to dig about 4 inches or so beyond where the shoots arise. A narrow and long spade (called a rabbiting spade) is a handy tool for this, especially in a closely planted border. Dig all the way around, then pry the clump out of the ground. Put down a tarp somewhere handy, and transport your clump there.
Pick up the clump and drop it a few times, to try and knock off any loose soil. Some gardeners will actually blast off the soil with a strong jet of water. Then, go and find a knife… I’m using an old kitchen bread knife these days for larger clumps, but a paring knife, steak knife or special garden knife will do just fine. Look closely at your clump, sort of parting the shoots in an attempt to find a natural point where the clump can be easily separated. If there is no such point, then just be brave and cut directly down the center with your knife, from top to bottom. Once it’s split in two, then look at each half to see if there is a sensible spot to cut yet again, then split these each into two. Depending on how large the clump was, you can keep going if you like. Try and keep the sections generally of a good size, say the diameter of your fist or larger. Each piece should have both green above-ground shoots as well as roots below.
Remember, unless you’re starting a nursery you probably don’t need 20 divisions of anything! The best and most vigorous pieces are usually those found towards the outside of the original clump. The roots are less woody and can recover more quickly, giving you strong and healthy new plants. Discard old and woody roots from the middle (add them to the compost pile).
Certain perennials when dug from the ground will almost fall apart into pieces. Others will need a lot more effort to split. A few kinds (like Miscanthus) may actually require an axe or hatchet to get out of the ground and then chop into smaller sections.
Once your dividing task is complete it’s time to replant the pieces. Try to plant them at approximately the same depth they were growing. Water them in well at planting time, then maybe once a week for the first month unless spring rains are generous.
One last idea
If you have loads of extra divisions, consider potting up a few of them for donations to your local Horticultural Society spring plant sale. Be sure to label them at potting time. These also make terrific and inexpensive gifts when visiting other gardeners.
— John Valleau, Corporate Horticulturist
Below are some books which contain lots of good information on gardening with perennials.
Tip from Misha Dubbeld:
Dividing grasses using a reciprocating saw (equipped with a large toothed pruning blade) is an easy way to make clean cuts and maximize divisions with a minimum of damage to the root system. It reduces the work by at least 50%. Just dig the grass out as a clump and make your cuts with the saw. This method even worked for the tough as nails Miscanthus Giganteus (floridulus). Reciprocating saws are inexpensive, light weight and quite safe to use.
L Westrand suggests:
A DeWalt D25980K Pavement Breaker Hammer
"My son did the muscle work! My garden benefited."
|L Bertrand's son dividing her grass with a DeWalt D25980K |
Pavement Breaker Hammer
Tip From Brad Weldon:
I use a reciprocating saw to divide the more vigorous grasses. It makes a nice and surprisingly clean cut.
Miscanthus 'Giganteus' is a great plant and I wanted to pass on a tip for dividing. I had a large clump of this in my garden and when I was moving. I wanted to take a piece with me. Two hefty guys plus myself and three substantial pry bars later we had the monster out of the ground. (The hole remaining looked like a bomb crater!) After several attempts at dividing using ever increasingly effective tools (or so we thought!) we finally resorted to a gas powered concrete saw! This we would recommend to anyone to use when wrestling with this specimen. it divided it up very neatly into 8 generous portions all of which survive in different locations around the Georgian Bay region of Ontario (Zones 4B to 5B).
P.S. We have quite a nice display of grasses at the Niagara Parks Botanical Garden, the 'campus' of the Niagara Parks School of Horticulture.
Tip from Bill Holt, Willowmist.com:
Use a hatchet or axe head (which you mention), but place it precisely where you want the cut and then pound it through with a heavy hammer, hand maul or sledgehammer. Much safer than axe swings, and even Grandma can do it - just takes her a few more hits. (I'm Grandpa. I know about this!)
Pics from Joe N., Ann Arbor, Michigan
A picture is worth a thousand words. Joe N. used an old handsaw and kept his lawn neat and tidy by putting a small tarp underneath. That made the clump easy to pick up and move while keeping the roots shaded. Smart Joe!
Tip from "Missouri Barb":
I helped a relative divide LARGE clumbs of Misicanthus on their farm using a fence maintence tool - a steel bar about 7 feet long and and inch in diameter, with a 2" wide chisel shaped end. The weight of the tool combined with its sharp narrow end allowed me to repeatedly drop it in one spot until I cut through the dense roots. By cutting wedge shapes, then digging around the root ball, we were able to remove sections from extremely dense clay soil with much less effort than one would expect. I believe the tool is used to tamp rocks around fence posts - sorry I don't know its name.
Donna sent us this link to a tool called a Digger / Tamper / Spud Bar, which seems to be what Barb was talking about above.
Here is a great discussion on GardenWeb Forum. Lots of great advice for dividing huge Miscanthus plants. (new link as of June 2015)
Clumps of tall, slender grass blades with interesting, feathery flower plumes make ornamental grasses such as miscanthus (Miscanthus spp.) a favorite with many gardeners. One of the most common varieties, Miscanthus sinensis, also called Japanese silver grass, is hardy in U.S. Department of Agriculture plant hardiness zones 4 through 9 and can grow up to 10 feet tall. Smaller cultivars, such as “Little Kitten,” reach only about 4 feet tall. Miscanthus needs an occasional pruning to keep its size under control. However, if your grass has outgrown its space or is turning brown in the center of the clump, the plant needs division.
Divide miscanthus in the late winter or early spring when it begins actively growing for the year.
Water the miscanthus plant one to two days before division. A well-hydrated plant is better able to handle the stress of division and will recover more quickly.
Remove an outer section of the miscanthus plant with a spade, digging about 8 inches deep and cutting under to get as much of the roots as possible. The section should be small enough to handle, about 1 or 2 square feet. Slice right through the roots as necessary. You may need an ax for thicker, more difficult roots.
Set the divided section aside in the shade. Moisten the rootball with water. On a hot, dry day, wrap the rootball in burlap and moisten.
Continue to dig out small, manageable sections of the miscanthus rootball. If the center of the plant is dead, dig it up and discard it. The divisions are now ready for replanting.
Zebra grass is similar to porcupine grass (Miscanthus sinensis 'Strictus'), another popular tall ornamental grass. The two look very much alike because they both sport horizontal stripes. But zebra grass has more of an arching habit, whereas the porcupine is more upright. You can easily remember the difference by considering the 'Strictus' cultivar name as "standing strictly at attention."
The arching habit of zebra grass can be a blessing or a curse, depending on your preference. If you are enamored with luxuriance, you will see it as graceful. But if you like things neat and tidy, you will perceive it as floppy and unkempt, perhaps in need of a good staking.
Upright in form, this grass makes a stand in the landscape with slender blades containing a white midrib. The feathery, cream-pink blooms give your garden a whimsical textural contrast throughout late summer and fall. Blooms a month earlier than Gracillimus and it's non-fertile so reseeding isn't an issue.
PPAF. Bred at University of Georgia. Introduced by Emerald Coast Growers.
Botanical Name: Miscanthus Scout™
Hardiness Zone: 5-9
Cut back in late winter close to ground if needed, divide in early spring before new growth emerges. Fertilize in early spring with organic fertilizer.
Plant Miscanthus Scout™ in full sun to part shade conditions.
Maiden grass benefits from regular watering and consistently moist soil during its first year. To establish long, healthy roots, water deeply to saturate the root zone. Maiden grass is a light feeder and too much fertilizer results in weak growth and a plant that falls over because it isn't sturdy enough to stand up straight. The plant benefits from an annual feeding applied before new growth emerges in early spring. Clumps of dry maiden grass provide winter interest to the landscape, but pruning in late winter or early spring removes old, dry growth and encourages the emergence of new growth. Cut the plant to about 4 to 6 inches, using sturdy garden pruners or hedge shears. Wear garden gloves to protect your hands from the edges of the dry blades of grass. Maintain the appearance and vitality of maiden grass by dividing it regularly. Plant the new sections immediately and water them thoroughly.