How to Take Root Cuttings: Which Plants, When & How

Most gardeners learn to root a piece of stem long before they ever cut into a root, but root cuttings are one of the most reliable and least appreciated ways to multiply plants. The method is simple once you understand it: you take a section of a plant’s root, store its energy reserves, and let it grow a brand-new shoot from scratch. There is no leaf to keep alive, no rooting hormone to fuss over, and no misting bench to maintain. You cut, you bury, you wait. For a whole group of plants that hate being divided and refuse to root from stems, this is the propagation method that finally works. This guide covers exactly which plants regenerate from roots, the narrow window when you can do it, and the precise technique — including the one rule that separates success from a tray of rotting compost.

What a Root Cutting Actually Is

A root cutting is a section of root, severed from the parent plant, that grows an entirely new plant. Unlike a stem cutting, it carries no buds and no leaves when you take it. Instead it relies on the plant’s ability to form what botanists call adventitious buds — new growing points that arise from root tissue rather than from an existing node. Not every plant can do this, which is why the technique is limited to a specific set of species. The roots have to be capable of producing shoots, and they need enough stored carbohydrate to power that first burst of growth before any green tissue exists to photosynthesize.

This is why dormancy is so important. When a herbaceous perennial dies back for winter, it pulls its energy down into the roots and crown. Those roots become reservoirs of sugars and starches. A cutting taken in midwinter is essentially a battery, fully charged, ready to push out a shoot the moment conditions warm up. Take the same cutting in summer and the root is depleted, busy supporting top growth, and far more likely to simply rot in the compost. Understanding that the root is a storage organ explains every step of the method that follows.

Which Plants Have the Right Kind of Roots

The plants that root well from root cuttings share a structural trait: they have either fleshy, energy-dense roots or thin spreading roots that naturally throw up new shoots along their length. If you have ever dug up an oriental poppy and watched it return from every fragment you missed, you already understand the principle. That regenerative habit is exactly what we exploit deliberately.

Herbaceous perennials with fleshy roots

The classic candidates are oriental poppy (Papaver orientale), acanthus or bear’s breeches, verbascum, echinops or globe thistle, eryngium or sea holly, and Romneya coulteri, the tree poppy. These all have thick, brittle roots roughly the diameter of a pencil or fatter. They also happen to be plants that resent being lifted and divided — poppies and sea hollies in particular have deep tap roots and sulk badly when their crowns are disturbed. Root cuttings let you propagate them without touching the parent’s crown at all, which is the whole reason the method matters for these species. Primula denticulata, the drumstick primula, also takes readily from root cuttings and is far easier to bulk up this way than by seed.

Plants with thin, wiry, spreading roots

A second group has much finer roots: border phlox (Phlox paniculata), Japanese anemone, and comfrey. These run thin, wiry roots through the soil, and each can generate a shoot along its length. The technique for these differs slightly because the roots are too thin to stand upright in a pot — but they are no less productive. Japanese anemone in particular is notorious for colonizing a border from the smallest scrap of root, which tells you exactly how willing it is to grow this way.

Edibles and vigorous spreaders

Horseradish, raspberry and blackberry all multiply enthusiastically from root sections. A bare-root horseradish “thong” is nothing more than a root cutting. Raspberries and blackberries naturally produce suckers from their roots, so a length of root buried in the right conditions reliably becomes a new cane. This vigor is useful when you want more plants, but it carries a warning we will come back to.

Woody plants that can be raised from roots

Several woody plants surprise people by rooting from root sections: sumac (Rhus), lilac (Syringa) on its own roots, trumpet vine (Campsis), and roses grown on their own roots rather than grafted onto a rootstock. The own-roots caveat is critical for roses and lilacs — if the plant is grafted, a root cutting will reproduce the rootstock, not the named variety you actually want. With genuine own-root specimens, though, a thick root section taken in winter will obligingly produce a shoot in spring. If you would rather propagate woody plants from the parts above ground, the related guide to taking hardwood cuttings covers the dormant-stem method that suits shrubs and many of the same species.

Exactly When to Take Root Cuttings

Take root cuttings during the plant’s dormant season — broadly late autumn to late winter, with midwinter being the sweet spot for most herbaceous perennials. The defining condition is dormancy: the top growth has died back or stopped, and the roots are full of stored energy rather than actively feeding leaves. In most US gardens that means roughly November through February, shifting earlier in cold northern zones and later in mild southern ones. Watch the plant, not the calendar. Once you see fresh shoot growth beginning, the window has closed for that year because the roots are committing their reserves to top growth.

There is a small amount of leeway by species. Plants with fleshy roots, like poppies and acanthus, are most forgiving across the whole dormant period. The fine-rooted plants such as phlox and anemone are best done a little later, toward late winter, so they spend less time sitting cold and wet before they are ready to grow. If your ground is frozen solid, wait for a thaw — you cannot lift roots cleanly from frozen soil, and frozen, brittle roots shatter rather than cut.

Step-by-Step Technique

Step 1: Lift the parent or expose the roots

For smaller perennials, lift the entire plant with a fork, working well out from the crown so you do not slice through the roots you want to harvest. Shake or wash off the soil so you can see what you are working with. For larger or established plants you do not want to move, scrape away the soil on one side and expose a few roots without lifting the whole crown — poppies and acanthus can be propagated this way with minimal disturbance, after which you backfill and the plant carries on unbothered. Whichever route you take, work in a sheltered spot or a frost-free shed so the roots do not dry out or freeze while you handle them.

Step 2: Select the right roots

Choose young, vigorous roots about the thickness of a pencil for the fleshy-rooted plants. These have the best balance of stored energy and the capacity to form buds. Avoid old, woody, dark or damaged roots — they are sluggish and prone to rot. Take only a portion of the parent’s root system, perhaps a third at most, so you do not weaken or kill the plant you are propagating from. With the thin-rooted plants like phlox and anemone, simply select healthy, firm sections of the running roots rather than worrying about diameter.

Step 3: Cut into sections — and respect polarity

Cut the selected roots into sections two to four inches long with a clean, sharp knife or secateurs. Here is the single most important rule in the entire process, and the one beginners most often get wrong: a root has a top and a bottom, and it must be planted the right way up. The end that was nearest the crown is the top; the end that was farther out toward the root tip is the bottom. If you plant a section upside down, it will not grow.

The trick to keeping track is to cut each end differently. Make a straight, flat cut at the top (the crown end) and an angled, slanted cut at the bottom. As you work down a long root cutting several sections in a row, the rhythm is straight cut, then slant, then straight, then slant. When you come to pot them, the flat end always points up and the slanted end always points down. This simple convention removes all guesswork and is worth following religiously. Lay your cut sections in a tray as you go so they do not get jumbled.

Step 4a: Insert thick roots vertically

For pencil-thick roots, fill pots or deep trays with a gritty, free-draining cutting compost — roughly equal parts multipurpose compost and horticultural grit or perlite works well. Use a dibber or pencil to make a hole, then push each cutting in vertically, slanted end first, until the straight top cut sits flush with the surface of the compost. Do not bury the top below the surface. Space them an inch or two apart; several will fit in a single pot. Once they are all in, top the surface with a half-inch layer of grit. The grit keeps the exposed cut clean, marks the level, and helps prevent the rot that comes from soggy compost sitting against the cut surface.

Step 4b: Lay thin roots horizontally

Thin, wiry roots — phlox, Japanese anemone, and similar — cannot stand upright and are handled differently. Fill a tray with the same gritty compost, firm it lightly, and lay the root sections flat on the surface, spaced apart so they are not touching. Polarity is far less critical with these because shoots and roots can arise along the length, but there is no harm in laying them as they grew. Cover the whole tray with about half an inch of compost and firm gently. No grit topping is needed here since nothing is left exposed.

Step 5: Aftercare — cool, and barely watered

Place the pots and trays in a cold frame, an unheated greenhouse, or a sheltered cold porch. The aim is cool and protected, not warm — you want the cuttings to stay dormant a while longer, not to be forced. Now the counterintuitive part: do not water heavily. The roots are full of moisture already and the compost only needs to be just barely damp. Excess water is the number one killer of root cuttings because the cut surfaces rot before they can callus and produce a shoot. Water lightly only if the compost is drying right out, and never let it become wet.

Be patient through the rest of winter. Nothing visible happens for weeks. Then, as spring arrives and temperatures rise, you will see shoots emerge at the surface. A crucial point to understand: with root cuttings, the shoots appear before the new roots do. The cutting throws up a shoot powered entirely by its stored reserves, and only afterward grows fresh feeding roots to sustain it. This is the reverse of a stem cutting, and it means you should resist the urge to disturb or pot on a cutting just because you can see a shoot — give it time to build a root system first.

Step 6: Pot on once growing

When a cutting has a healthy shoot and you can see, by a gentle tug or by tipping the pot, that it has made new roots of its own, pot it on into its own pot of ordinary potting compost. Grow it on in the cold frame or a sheltered spot through spring and summer, hardening it off gradually, and plant it out into the garden in autumn or the following spring once it is a robust young plant. Resist planting tiny rooted cuttings straight into the open ground where slugs, weather and competition will quickly overwhelm them.

Why This Method Matters for Tap-Rooted Plants

The real value of root cuttings becomes obvious when you try to propagate a plant that simply will not divide. Oriental poppies, sea hollies, acanthus and verbascums all form deep tap roots and resent having their crowns split. Dig them up to divide and you often end up with a sulking, half-dead clump and no reliable increase. Root cuttings sidestep the problem entirely: you take a small portion of root, leave the crown intact, and raise as many new plants as you have root sections. For these species it is not merely an alternative to division — it is frequently the only practical way to make more of them at home.

It is also a genuinely productive method. A single decent root system can yield a dozen or more cuttings, and the success rate with the right plants taken at the right time is high. If you enjoy this kind of low-tech, high-yield propagation, the same satisfaction is on offer with the related layering technique for plants that root where their stems touch the ground, and across the broader range of methods gathered in the outdoor living and gardening hub.

A Word of Warning: The Same Trait That Helps Can Spread

The willingness of these plants to grow from root fragments cuts both ways. The very vigor that makes horseradish, brambles, Japanese anemone and comfrey easy to propagate is also what makes them potentially invasive. Every scrap of root left in the soil — whether from cultivating a bed, dividing a clump, or simply trying to dig the plant out — can become a new plant. Horseradish in particular is almost impossible to fully eradicate once established, because any root fragment regrows. Site these spreaders deliberately, consider containing them in a buried pot or a dedicated bed, and dispose of unwanted root pieces by drying or hot-composting rather than tossing them onto open soil where they will happily take root and run.

If your real interest is in propagating shrubs and climbers rather than herbaceous perennials, it is worth knowing that stem-based methods often suit them better at different times of year. The semi-ripe cutting method taken in late summer covers a huge range of woody plants and is a useful companion technique to keep in your propagation toolkit alongside root cuttings.