Miscanthus - looking after ornamental grasses?

Hi Lindsay.
I've got a type of Miscanthus sinensis. It's the type known as Zebra grass. It has horizontal stripes, grows tall (about 6') and has wonderful pink plumes in Autumn. I split mine last year into two. It was still relatively young, lass than 2 years. It survived the split and both plants grew well. I split it in the Spring. I think you should try splitting, but if it's huge it will be a hefty job. I recently split a pennisetum (fountain grass), about 3 years old and it was all I could do to dig it up. I nearly had to call for male assistance but finally I managed it. Hope yours does well. I think Miscanthus are pretty robust. I'm only speaking from personal experience not horticultural knowledge. One of our experts might advise you differently.
Chris

Hi Lindsey - now is definately the time to split Miscanthus sp. They might sulk a bit this year, but they should do ok. If you've had disasters in the past doing this, I wonder whether you split your plants at the right time of year? If you do it in summer, there will be too much stress on the plant, having to grow, cope with low water levels etc without the benefit of a well established root system. Good luck!

Lindsey - Good general advice from Chris and Sid. I have been growing ornamental grasses for the best part of 20 years and so I might be able to add a little more info that might also be useful. First step is to cut the grasses back hard, if you haven't already done so, this also goes for your Stipa, it will do no harm at all. February and March is the best time to do this task for all ornamental grasses. if your Miscanthus is indeed five to six years in the ground, it will be no easy job to lift and divide, plus depending on what cultivar it is regards to individual vigour. If you decide to lift it, it's my guess you will need help. The roots do not go deep, but they are fiberous, very compact and solid, making the detached rootball extremely heavy for lifting, again a two person job. Once you manage to get the plant out of its hole I would advise you use a saw to divide the plant, a spade is unlikely to be up to the job. Use the outer more vigorous pieces for replanting, discard the dead center. If it does prove difficult or inpractical to lift the whole plant, it is possible to severe the roots and undercut half the plant in its original position, again use a saw to divide in two (this is possible with the plant still in the ground) then remove the detached half, and backfill mixing in some additional compost/leafmould, etc, this will help rejuvinate the original old centre of the plant. Hope this helps.

Thank you all for your helpful comments. I spent most of yesterday morning trying to dig the miscanthus up, (or even half of it!) and had to acknowledge defeat in the end. The situation isn't helped by the fact that its planted in gravel which seems to have got right into,the heart of the plant as well as all around it, and also it's in a corner bounded on 2 sides by a wall, making access very difficult. Oh dear! However, now that I've read your advice I've got a better idea how to tackle it (and what I'm letting myself in for) I don't think I would ever have thought of using a saw either, what a good idea!
Thanks again,
Lindsay.

I have a Miscanthus sinensis Purperesens and always cut it right down about now, just as the new growth is beginning to show through. Although I have not divided it yet (and it must be about due) I did dig it up and relocate it last year, again around March time. No harm done at all - except to my back I would say! As Bluespruce rightly points out, Those things weigh a ton.