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    Herbaceous perennials are the chorus line of garden plants. Coming back year after year filling your garden with wonder. They provide structure and interest to borders and if well planned can ensure seasons of interest right up until early winter. Whilst they perform with little assistance from us gardeners, careful pruning can help you get the most of out them each year. This guide will help you know when and how to prune pretty much all herbaceous perennial plants.

    Pruning back herbaceous perennials is essential to ensure beautiful blooms in your garden year after year. However, many gardeners are confused about when and how to prune. Most new gardeners leave herbaceous perennials like Salvias, Heleniums or Verbenas, expecting them to regenerate themselves the year after magically. The fact is, they won't. All herbaceous perennials need pruning back to the ground at the end of the year to enable them to regenerate.

    However, most people struggle to know when or how to prune this plant group.

    With annuals, it is easy; at the end of the summer, you lift them and compost them, but with herbaceous perennials, there can be that awkward moment in Autumn when you're unsure what to do. When should you prune back herbaceous plants? Is it September or February? The quick answer is either way, but I'm going to advocate for leaving them until February to help wildlife.

    This guide gives you all my top tips for when and how to prune herbaceous perennials.

    Herbaceous Beginner Pruning Guide

    1. How to identify a herbaceous perennial
    2. When to prune herbaceous perennials
    3. The best tools for pruning herbaceous perennials
    4. How to prune different types of herbaceous plant
    5. How to know what to prune in winter
    6. Can you compost herbaceous plants?
    7. Will frost damage herbaceous perennials?
    8. When is it too late to prune plants?
    9. Should I leave my herbaceous plants through the winter?

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    How to identify a herbaceous plant

    Herbaceous perennials can be easily identified as this plant type, which will come back year after year, dying back each winter and regenerating each spring. They put on fresh green vegetative growth each year and then die back underground. Herbaceous plants usually have a root, bulb, corm or underground storage system that survives throughout the winter.

    Herbaceous perennials don't require the care and attention of annuals or bedding plants, as the majority of them are fully hardy (there are exceptions, as with anything). This means herbaceous perennial plants will happily survive underground during the harsh winter frosts and arise again in the spring to dazzle us with their offerings.

    Top 30 UK Herbaceous Perennials

    To help you identify herbaceous plants, those that come back each year, I've listed below the top 30 here in the UK so you can easily see in your own gardens what will need pruning back each year.

    1. Geranium (Cranesbill)
    2. Helleborus (Hellebore)
    3. Hosta
    4. Alchemilla mollis (Lady's Mantle)
    5. Aquilegia (Columbine)
    6. Astilbe
    7. Sedum (Stonecrop)
    8. Echinacea (Coneflower)
    9. Kniphofia (Red Hot Poker)
    10. Lupinus (Lupin)
    11. Rudbeckia (Black-eyed Susan)
    12. Salvia
    13. Aster
    14. Anemone
    15. Phlox
    16. Campanula (Bellflower)
    17. Delphinium
    18. Digitalis (Foxglove)
    19. Heuchera (Coral Bells)
    20. Monarda (Bee Balm)
    21. Penstemon
    22. Pulmonaria (Lungwort)
    23. Veronica (Speedwell)
    24. Nepeta (Catmint)
    25. Coreopsis
    26. Verbena bonariensis
    27. Gaura
    28. Geum
    29. Dianthus
    30. Sanguisorba

    The key to spotting a herbaceous perennial vs a shrub is that herbaceous plants don't put on woody growth in their stems like shrubs.

    They are easy to spot as the first frosts of winter will turn them brown and crispy. Quite often, beginner gardeners think they are dead, but they are not.

    Brown or dried-up herbaceous perennial plants in late autumn and winter are simply dormant.

    A garden full of red heleniums

    They keep their energy underground in the crown and root system of the plant. Allowing the vegetative matter to die back once the plant has set seed in summer.

    Two examples of a herbaceous perennial would be a Helenium which is your typical daisy-like flower, but then also a Banana plant (Musa basjoo) which, believe it or not, isn't a tree but a herbaceous perennial. The largest herbaceous perennial in the world, growing upwards of 3m each year and dying back!

    When to prune herbaceous perennials

    The best time to prune herbaceous perennials is late winter in January to February.

    Most gardeners have a habit of pruning herbaceous perennials at the end of Autumn. This occurs during the great garden tidy-up at the end of the season when gardeners are frantically trying to tidy up it seems. I'm not sure what it is with us Brits, but we do tend to love a good clean up and tidy.

    What I find is that you may remove the dried-up stems of herbaceous plants to make the borders look tidier, but you're left with bare earth and spaces in your garden.

    I advocate a different approach of pruning or tidying back herbaceous plants, like those in the Exploding Atom Garden, after winter around late February here in the UK.

    Pruning in late Winter is far more beneficial, both visually and for wildlife. The reason for this is that herbaceous plants such as Salvia, Miscanthus, Geums and Foxgloves act as a really good food source for wildlife during the barren winter months.

    Seed heads provide easy snacks, and other insects that take refuge around these plants help keep our wildlife alive during winter when food sources are scarce.

    Secondly, the dried-up stature of these plants can look incredibly beautiful during the winter. Grasses with their light brown stems frozen in time and seed heads of taller herbaceous plants like Acanthus can extend interest in the garden.

    Benefits of leaving herbaceous plants until winter:

    • Herbaceous plants in winter give wildlife a valuable food source
    • Herbaceous perennials look far nicer for winter structure in the garden
    • They offer shelter and a windbreak for hibernating creatures
    • It's far less work for the gardener

    Who wants to look at bare soil when you could be looking at arrangements of ghostly sepia-toned herbaceous plants?

    dried herbaceous border flowers

    Look at how interesting this is in the dead of winter. If it were bare earth, it would look barren. The grasses against the Carpinus tree and crisped-up Heleniums look wonderful and are great for wildlife in the garden. Pruning herbaceous perennials in early autumn can reduce their interest in your garden, and this is why I advocate leaving them until late winter.

    Best tools to prune herbaceous plants

    When it comes to pruning herbaceous perennials, it's important to have sharp, clean, and suitable tools for the job. Using old rusty secateurs or pruning sheers will damage your plants and potentially lead to infection and disease.

    Two tools are essential when pruning these plants back in winter

    1. Secateurs
    2. Japanese scythe (especially for larger grasses or big gardens as they are faster than secateurs)or breadknife
    A japanese garden scythe

    If your secateurs look old, rusty, or blunt, follow my secateurs sharpening guide here. It's worthwhile spending 10 minutes cleaning and sharpening them. It will save you time in the garden and protect your plants from awkward rough cuts or being torn at the base.

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    How to prune herbaceous perennials

    Pruning herbaceous perennials is super easy. It's a case of cutting them back down to between 2 and 6 inches from the ground, depending on the size of the plant. For really tall grasses or Banana plants, 6 inches is enough. For a tiny Geum or Geranium, then 2 inches is sufficient.

    Take a look at the flower bed below before pruning. See the grasses and other herbaceous perennials that have turned brown over the winter.

    Herbaceous border before pruning

    With a sharp pair of secateurs or a Japanese scyth, snip back old the old growth and compost it. See below how much has been removed and to what height. All neat clean cuts and the clippings have been composted.

    Herbaceous border after pruning in winter

    How to know what plants to prune back?

    To make it easy for beginner gardeners, I split herbaceous perennials into three main groups to help gardeners in knowing what and when to do. Even if you don't know the exact name of the plant you're dealing with this guide should help you to identify the pruning method required.

    1. Ground cover herbaceous
    2. Tall herbaceous perennials
    3. Evergreen herbaceous plants

    You're going to need sharp clean secateurs, gloves and a bucket.

    Gareden Ninja holding secateurs

    Pruning Group 1: Ground Cover Herbaceous Perennials that die back

    Ground cover plants are relatively easy to maintain. They tend not to look too messy as they are closer to the ground, so as they die back, they are pretty low maintenance. Needing very little pruning back. But sharp secateurs make it easy to cut off the brown bits.

    I cut ground cover herbaceous perennials back to 2 inches above the ground of 5-6cm. You can usually see a crown of green growth just above the soil level. So cut above this.

    Examples of ground cover plants:

    • Geraniums
    • Alchemilla
    • Geums
    • Lamium
    • Pulmonaria
    • Stachys (Lambs Ear)
    • Creeping plants

    The issue you may find with ground cover plants is if there's a hard frost, the leaves can turn mushy and sometimes grow fungus. This is not good for plant health, so if this is the case, remove them in early winter. Stachys is an excellent example of a plant that needs an earlier prune.

    If not, I always leave them and tidy them up at the end of winter just before spring.

    ground cover plant pruning

    Even plants seemingly surviving the winter need to be cut back to the ground. This is because the old growth will be weak, and you want the plant to send out vigorous new growth. So don't be tempted to try and salvage this group; be brutal, and you will be rewarded!

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    Pruning Group 2: Tall Herbaceous Perennial Plants

    Group 2, the taller herbaceous perennials, is probably the most interesting, in my humble opinion, especially in winter. This group will keep the drama alive in your garden even during those dark miserable winter days. They are also more likely to have seed heads that provide sustenance for wildlife.

    Examples of taller herbaceous perennials:

    • Heleniums
    • Salvias
    • Grasses (Miscanthus, Panicum, Calamagrostis)
    • Rudbeckia
    • Physostegia (Obediant Plant)
    • Eryngiums
    • Penstemons
    • Verbena
    • Monarda

    Most people seem eager to cut down this group at the end of Autumn. I affectionately call this group the 'Brown and Crispy Crew'.

    pruning herbaceous perennials

    However, I really do advocate that you leave the 'Brown & Crispy Crew' and see just how effective they are at keeping interest in your borders through the winter. You may even see small birds using them as perches or some insects working away on them throughout the winter.

    Pruning this group is super easy. I tend to prune these towards the end of February to ensure that any new early growth has a free run. With a clean, sharp pair of secateurs, you will cut down the 'brown and crispy crew' to just above ground level, around 3 inches to 6 inches, 6cm to 12cm.

    Some plants, like Penstemons, have delicate crowns, so you may want to leave these for another month or so. In most cases, though, a late February chop is fine.

    Plants are tougher than you think, and it also allows you to plan the border for that year by seeing it without distraction. It also means you are able to look at your flower beds and identify any potential issues before the spring starts.

    With sharp secateurs, cut this group back down to the ground - you can compost the cuttings.

    This tall Salvia 'Blue Enigma' gets cut right back down to the ground.

    Pruning Group 3: Evergreen Herbaceous

    This group is probably the easiest to deal with as all you're doing is a light tidy-up of any dead or damaged matter. Most of this category falls under ground cover, so any carpet-like plants that keep their colour through the winter or a large portion of the Fern family fall into this group or anything with a glossy green leaf.

    Examples of Evergreen Herbaceous Plants:

    • Ferns
    • Agapanthus
    • Ajuga
    • Helleborus
    • Galium
    • Carex
    • Asarum europaeum
    • Euphorbia
    • Bergenia (Elephants ears)
    • Evergreen grasses (Stpia gigantea as an example)
    pruning evergreen perennials

    For ferns, all you need to do is selectively remove any leaves or fronds. Berginia only needs a light clear-up. Take out any old crispy leaves as they flower early in the season, so don't be too heavy-handed.

    With evergreen grasses, like Stipa gigantea, lightly pull out any old spent flowers and use secateurs (with gloves as the leaves are sharp) to cut out any damaged leaves.

    With Carex or Helictotrichon grasses, you can run your fingers through the grass and pull out any dead matter.

    Evergreen herbaceous perennials only need a light tidy-up in later winter. Pruning should be light touch. When pruning evergreen plants in autumn or winter simply cut off with secateurs anything that is:

    • Damaged
    • Diseased
    • Chewed
    • Frost burnt
    fern pruning
    Ferns can be in Group 1 (deciduous) or Group 3 (Evergreen); if they're in bad shape, a quick neatening is usually enough, so take them back to the ground.

    If you're a bit late in pruning your herbaceous plants, I would advise you to prune out all the dead material still; don't go so far to the ground.

    If you're pruning later in March or April, you want to avoid severing any new growth. However, in my experience with herbaceous plants, late pruning is always better than no pruning.

    Can you compost herbaceous cuttings?

    Yes, you can! All herbaceous clippings can be composted and should be reused and recycled in the garden. They make excellent woody material for compost bins, especially if you've got lots of green matter, such as grass clippings. These herbaceous perennial prunings are known as 'browns' for your compost bins. Always aim for a mix of 50% greens (fleshy wet ingredients like kitchen scraps) to 50% browns (like twigs, dried herbaceous perennials and cardboard).

    I've even used a shredder in wildlife gardens to cut down the herbaceous clippings and then used them as mulch on the borders, meaning nothing goes to waste or landfill.

    If you haven't already considered creating a compost bin, I would urge you to read my speedy guide here. All gardens, no matter what size, can fit a small compost bin in to close the loop

    Recycling plants by composting

    Will frost damage my herbaceous perennials?

    The quick answer is not very often. Herbaceous perennials are tough plants, and while dormant, their roots, crowns, and bulbs will be well protected from sub-zero weather. These plants are adept at surviving long winters and know the optimal time to pop back up in Spring.

    If you're wondering if to hold off from pruning as there's going to be a frost again, my answer is not to worry too much. Pruning back old growth can't harm herbaceous plants. That's because the brown and crispy stuff is already dead.

    Yes, it will give some protection from sinking frosts, but for the most part, you'll be fine pruning late winter, even if a March or April frost appears. These plants are tough.

    If you're concerned about Penstemons and other more tender perennials, then why not layer your clippings on top of the crown until springtime? That way, you get the best of both worlds!

    When is it too late to prune plants?

    It's never too late to prune plants, but there is a best time vs the most difficult time. The best time to prune herbaceous perennials is late winter before the new growth. If you're in April or May and you've still got last year's dead plant material stuck to them, you can still prune this away.

    The biggest problem with late pruning is you can't simply hack the plant back to the ground, as you'll cut off all the new growth in the process. You'll need to carefully remove the dead parts bit by bit with secateurs, not the Japanese scythe.

    Problems with late pruning plants:

    • It's time-consuming
    • It hinders the plant's current growth as old matter gets in the way
    • There's a high likelihood of cutting off new growth by accident
    • Your garden will look messy whilst old and new growth merge

    Should I leave my herbaceous plants throughout the winter?

    Absolutely, you should! Leaving your herbaceous plants to crisp up during the winter is a vital food source for wildlife and offers protection. Beneficial insects will overwinter in the leaf folds, seed heads, and debris on the bottom of these plants.

    Lacewings, ladybirds and other insects will be hibernating or overwintering, so cutting back herbaceous plants in Autumn makes it harder for them to survive.

    Lacewing bug hotel information

    Leaving herbaceous plants over winter also protects the soil. They act as a protective fleece layer from extreme frost and heavy rainfall. They stop the wind from scraping the soil's surface and are an all-around great protective layer.

    By leaving the herbaceous plants through the winter, you also save yourself time at the end of a busy growing season. Putting off that work of pruning until the end of winter gives you, the gardener, much-needed time to relax!

    Learn how to Design Your Own Garden

    Now that you know how and when to prune back herbaceous perennials why not learn more about how to design your own garden?

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    Summary

    Pruning herbaceous perennials late in the winter is the sensible option for you, the gardener and wildlife. By following this guide, you can easily prune back all plants, even if you don't know the exact name of them!

    Do you have your own preferred pruning time or method for pruning herbaceous perennials? If so, I'd love to hear from you. Also, why not send in some pictures of your pruning so we can spread the word to other new gardeners on Twitter?

    You can TweetFacebook or Instagram me with your garden questions, pictures or comments. If you're looking for more tips on garden design, tricks, and hacks, why not subscribe to my YouTube channel?

    Happy Gardening!

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    Plants used for "How & when to prune back herbaceous perennials"

    Group 1 Ground Cover Examples
    • Alchemilla mollis
    • Lamium
    • Geraniums
    • Fleabane
    • Pulmonaria
    Group 2 Tall Herbaceous 'Brown & Crispy'
    • Salvia
    • Verbena
    • Asters
    • Rudbeckia
    • Echinacea
    • Achillea
    • Monarda
    • Grasses (well some)
    • Heleniums
    Group 3 Evergreen Herbaceous
    • Galium
    • Epimedium
    • Ferns (some)
    • Hellebores
    • Carex

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    2 thoughts on “How & when to prune back herbaceous perennials

    1. Mark stewart says:

      Hi garden ninja I have a question on a few herbaceous perennials
      The plants I have currently in the border (I intend hopefully to add some more)are coreopsis,osteospernums,salvias,lavandula, antirrhinum s, digitalis,calynopsis,campanula, dianthus,and senetti,I only planted these in the garden early last summer,so I avoided cutting them back in autumn is it alright now to go ahead and cut them back now late February?many thanks
      Kind regards mark

    2. lee says:

      Hi Mark,

      Thanks for your comment. Yes, if you cut them back now that’s ideal before the new growth. Then they will be good to bloom this year! Happy pruning. Lee!

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