Pruning Pampas Grass: When and how to prune Pampas Grass plants

When it comes to large grasses, not many varieties of grasses make more of a statement in the garden than an established pampas grass with tall swaying plumes. I’ve been a professional gardener for over 20 years and have worked in my family’s small nursery for as many years. I often get asked ‘when and how to prune pampas grass?

I first covered this in my Pampas grass growing guide, which covered planting, general care, and diseases. However, in this guide, I want to focus solely on How I go about pruning pampas grass.

When I started gardening many years ago, setting fire to pampas grass to burn them back was standard practice. However, this differs from what I recommend now as it’s not environmentally friendly and can damage the crown. The good news is that pampas grass responds very well to hard pruning, and assuming it is done at the right time of year, it’s nearly impossible to do it wrong. They grow amazingly well after pruning, and you can even divide them every few years to control their size, but more on this further down.

Before I get into my more detailed pruning guide below, it’s important to prune them when the risk of a hard frost has passed and, ideally, new growth is emerging from the centre. Ideally, this is late winter to early spring, so anytime from late February at the earliest if it’s mild, March or even into early April, as I usually do for my customers.

All you need is a good pair of garden shears or you can even use a hedge cutter as I do to speed up the process. Then, a good pair of loppers to cut through the thick centre stems. This year, I used my Stihl mini chainsaw, and it did a great job. I also use my DeWalt cordless hedge trimmer to remove the outer foliage instead of a pair of shears as it speeds up the process. The main thing is, don’t be afraid to be brutal when cutting them back. I cut mine back to 1-2ft which is still on the high side, and it always responds very well.

To learn more about my process, read my full guide below:

Did you know one variety of pampas grass can be grown in a container, check out which type you can grow in containers here

Get the timing writing when it comes to pruning

Pampas grass is best pruned in late winter and can be pruned back once a year once it is established or even every few year if it had plenty of space to spread. Ideally, you want to prune around late February, March or even early April, as I recently did. If you prune them late winter rather than in the autumn you can still enjoy those fantastic flumes they are so famous for. The dead foliage also helps protect the crown over winter from hard frost. Ideally you want to prune then back just as the new growth shoots in the centre.

Pruning pampas grass

So for the few years, you usually don’t need to hard prune pampas grass, in fact, it was 5 years until I pruned my own pampas grass back hard. Previously, I just gave it a general tidy-up, removed dead leaves, removed the old flower spikes, and it was looking good again.

However, once it’s established, it’s actually better to give it a hard prune every year or at least every other year. You can cut them back to near ground level but ideally, you want to cut it back and try to leave the new growth. They are very forgiving plants so don’t worry too much, it really is hard to do any serious damage to them.

Consider dividing pampas grass to control the size

If you want to control the spread, you can consider splitting the pampas grass and dividing it. Once you have cut back the pampas grass hard, you simply dig around the root and lift the pampas grass from the soil. Then, cut the whole pampas grass in half with a spade and use two forks back to back to prise the two sections apart. Replant one section and plant the second section somewhere else or dispose of it.

Don’t forget to remove new side clumps to avoid overcrowding

When you do your annual pruning you might notice new clumps of pampas grass forming their own, smaller clumps off to one side or another. You want to remove these when you do your regular pruning so that your pampas grass in an overcrowded and it just helps keep it a little more under control.

Watch out for sharp foliage

Pampas grass has very sharp foliage, so this is not something you want to tackle in your shorts and T-shirt. Make sure you have a good pair of gloves, a long sleeve shirt or coat and even some safety glasses before attempting to prune a large pampas grass.

What tools you need

Pampas grass has very thick stems so you need something substantial to cut through them. I usually use a cordless hedge trimmer to trim the side foliage off quickly, although you can use a good pair of garden shears, and you will need some sharp garden loppers to cut through the thick stems or a mini chainsaw.

Check for animals living in the pampas grass before pruning

Before you trim the pampas grass with a pair of shears or a hedge trimmer, check for any animals that have made them home inside. I actually found a large toad living at the base of mine, which I moved to safety.

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Last update on 2024-11-19 / Affiliate links / Images from Amazon Product Advertising API