Why do they die?

Laurel, DE(Zone 7a)

I have noticed that over the course of about 8-10 years the center of my tall grasses/miscanthus die out and leave just an outer ring of growth. It has happened to all sorts of grasses even zebra grass.
Why does that happen and how can I fix it if possible?
Thanks in advance.

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This message was edited Feb 5, 2016 7:14 AM

Elgin, IL(Zone 5a)


I am very sorry.

I have had numerous miscanthus from 1998 to 2011 when I sold my house. The only grass that tended to die out in the center was silberfeil, an old cultivar that I replaced. The rest, gracillimus (8), adagio, bluttenwunder, silberfeder, Huron Sunrise and Morning Light (5) did not do this.

The biggest single reason is a failure to cut back grasses before they emerge in spring. If grasses are not cut back light never reaches the interior of the plant, and the center dies out. It's worst with tall grasses because the center is farthest from the sun. I bought at least 30 grasses from Milaegers in Racine, and he also told me that, after cutting them back, give them a little 10-10-10 fertilizer.

Have you been cutting them back? It has to be done every spring.

The remedy is tough. You need to dig them up, remove the dead sections and replant them.

Your list, by the wa, does not work.

Laurel, DE(Zone 7a)


This message was edited Mar 11, 2015 4:10 PM

Laurel, DE(Zone 7a)

Back in hagerstown I cut them back every March 5. They lasted for many years, but before we moved two had dead centers. We moved to Delaware I. September and there are five grasses, 3 with dead centers.
I noticed because I just went out on March 5 and cut them back.
Thanks for all the info, will perhaps dig out the dead ones and replant with zebra grass.
Disregard the above quote lol, fingers ran amuck.

What miscanthus would you recommend for the eastern shore?

This message was edited Mar 11, 2015 4:11 PM

Elgin, IL(Zone 5a)

Careful - miscanthus zebinus (zebra grass) is a renowned flopper.

If you like the look, try miscanthus Sritctus. Lovely grass. I had two. And they stay upright! Left in the pic - avoid silberfeder (right) - it flops!

Thumbnail by DonnaMack
Laurel, DE(Zone 7a)

Thanks for the advice. I had the zebra grass you show on the left hagerstown and it was lovely. I also had one similar to the other and liked the way it spilled over, however it had a lot of striping in it. Not really important that they stand straight to me. I had about 6 varieties up there and they all spilled over. A pain when time to cut back, but other than that they liked nice.

This message was edited Mar 16, 2015 7:12 AM

Everett, WA(Zone 8a)

I wonder if grass flops for the same reason my lavatera flopped. I think they had soil that was too fertile, too well-watered and too aerated.

Maybe giving it less water, less fertilizer, and worse soil would make it stand up instead of lying down on the job.

A seemingly-identical lavatera grew on a little raised hump of hard, dry clay and always stood up straight and grew perhaps 5-6 feet tall each year.

Mine, (sold as [i]Lavatera thuringiaca[/i] 'Barnsley', a "periclinal chimaera" from Hirt's Nursery, that looks exactly like the cheaper, common cultivar [i]Lavatera thuringiaca[/i] 'Rosea') shot up quickly to 7 feet, then flopped over and grew horizontally to 8, 9 or 10 feet, laying on the ground. I think that was because i planted them in my best beds where they would be watered often and the soil was as good as I could make it while still being kind of cheap about purchased compost.

Elgin, IL(Zone 5a)

You nailed it, Rick. Grasses do much better on soil that is crummier, fertilizing mildly at the beginning of the season after being cut back, holding back on the water (I never deliberately watered mine) and holding back on the compost I threw everywhere else resulted in grasses that don't flop, except for silberfeder and zebrinus, which flop no matter what you do.

Laurel, DE(Zone 7a)

That. Oils be part of my rotting center problem down here. The ground is mostly sandy and the rains flood everything. Likely the dense centers of the clumps are holding a lot of water and causing the rot.

Magnolia, TX(Zone 9a)

Sometimes it is the search for light that walks the grass out into a circle- and sometimes it is the soil has changed so that the roots search for an area they havent been and depleted the soil of what that grass liked. Too much water does make grasses top heavy as well.

Laurel, DE(Zone 7a)

Thanks for the info.

Jackson, MO(Zone 6b)

How much "stem" should you leave when you cut the grass down?
Have a neighbor with lovely grass who cut his back to about 3' in the fall. It looks silly now: kind of like a flat 3' table.

Elgin, IL(Zone 5a)

I have always cut mine down in the spring. If you have bulbs around the grasses it looks a lot less dumb. Late March was always my target. Possibly early April. Crocuses and iris reticulata are nice

Do you mean three feet or three inches? Three feet is definitely too tall. Six inches would be better in terms of getting light to the base of the grass.

Jackson, MO(Zone 6b)

3 feet. That's why I think it looks silly. It's also such a waste of a nice landscape plant in winter.

Elgin, IL(Zone 5a)

I agree. I leave mine up all winter.

Laurel, DE(Zone 7a)

I think the main reason to have miscanthus is for the winter interest. I cut mine back every March 5. That way they are of lovely interest all winter and come back quickly in spring and summer.
My large ones I cut back to the same height every year which is about 18-24". As they get more dense with years of growth it is difficult to. Us them any further than the previous year. For my large ones we tie a rope around them. Pull it tight and cut below the rope line, then it is all bound up for disposal on the compost.

Elgin, IL(Zone 5a)

Hi Laurel,

Some of mine were really mature, so I would tie them with duct tape and then use a chain saw. Then put them in leaf bags and cut the duct tape off, since I'm pretty sure you can't recycle it.

We have a treat here. My community add $2 a month to everyone's garbage collection fee, and then, for four months out of the year, you can put yard bags and leaves and branches (no more than two inches thick or five feet long) on the curb and they will dispose of them for you. Since stickers for bags are about $2.50 each, if you use the service it's a steal. One weekend I put out 12 bags of leaves and debris - I could only use so many for compost. So the grasses go in yard bags or, alternatively, I tie them with cord or rope and put them out.

I love miscanthus in particular because of the transition from summer to fall and the lovely colors. And the winter interest is a special bonus! Panicum is nice - I've just added some - but I do think that nothing beats miscanthus for winter interest.

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