Take Root Cuttings This Winter: 12 Perennials That Regrow From Root Pieces

Oriental poppies vanish underground every summer and spend autumn dormant below the soil — invisible, apparently dead, yet packed with stored energy. That same root system is quietly doing something useful: concentrating carbohydrates in preparation for spring. Dig a few pencil-thick sections in November, cut them to length, tuck them into gritty compost, and by late spring you’ll have a pot full of new plants — no heat mat, no misting bench, no rooting hormone required.

Root cuttings work because plants store energy in their roots, and that storage peaks during dormancy. The technique differs from stem cuttings in almost every way — including the polarity rule that determines whether the cutting produces a shoot at all. Understanding that rule is the difference between a successful tray of new plants and a pot of rotted root pieces.

This guide covers 12 perennials that respond well to root cuttings, the two techniques matched to root thickness, and the biology behind the right-way-up rule that most guides mention but never explain.

Why Winter Is the Best Time to Take Root Cuttings

Timing root cuttings to the dormant season isn’t tradition — it’s biology. As a perennial dies back in autumn, it stops pushing energy into leaves and stems and instead pulls carbohydrates back into the roots for winter storage. Root sections taken at this peak carry the most stored energy, which is exactly what they need to generate adventitious buds and push up new shoots without any connection to the parent plant.

According to NC State Extension, root cuttings should be taken from 2- to 3-year-old plants during dormancy specifically because carbohydrate levels are highest at this point. Once spring arrives and buds begin to swell, that stored energy starts redistributing toward new growth. Cuttings taken after the plant breaks dormancy are working with a depleted energy reserve, and success rates drop noticeably.

The practical window runs from mid-autumn through February. November through January tends to be the sweet spot; December is often cited as optimal because most perennials are fully dormant and root carbohydrate concentrations are at their peak. You can push into early February for most species before the risk of bud break rises.

One underappreciated advantage: root cuttings come from below ground, so they carry none of the foliar pests or pathogens that can follow stem cuttings into your propagation tray. If you’ve been fighting powdery mildew on your garden phlox, root cuttings let you start completely clean.

12 Perennials That Propagate From Root Cuttings

Root cuttings work best on species with relatively thick, fleshy roots that carry meaningful carbohydrate stores. Within that group, root thickness determines which of the two methods you’ll use: thick roots are inserted vertically, thin roots laid horizontally.

The distinction between thick- and thin-rooted plants isn’t just about size. Thick-rooted plants like oriental poppy and verbascum have concentrated energy reserves along the root’s length and form a shoot from a single point near the proximal end. Thin-rooted species like phlox distribute energy more diffusely and can produce shoots from several points along a horizontal cutting.

Two plants deserve special mention: comfrey and acanthus. Both are so capable of regrowing from root fragments that even small pieces left in the ground become new plants. This is useful when propagating intentionally — and a nuisance when you’re trying to move or remove them.

What You’ll Need

• Garden fork — for lifting root sections without snapping them
• Sharp knife — a clean cut is essential; crushing or tearing the root end invites rot
• Gritty cutting compost — equal parts peat-free compost and perlite or coarse grit; keeps moisture consistent without waterlogging
• Module trays or deep pots — at least 3–4 inches deep for vertical sections
• Labels — root cuttings are completely unidentifiable once buried; label every tray the moment you fill it
• Rooting hormone (optional) — most root cuttings don’t need it, but echinacea and verbascum show modest improvement with a light dusting of IBA powder on the proximal (top) cut end

Step-by-Step: Taking and Planting Root Cuttings

The process divides into two tracks based on root thickness. The right-way-up rule applies to both — the next section explains the biology — but the orientation is built into the cutting and planting steps described here.

For thick-rooted plants (oriental poppy, verbascum, comfrey, hollyhock, sea holly, echinacea, acanthus)

1. Lift the parent plant carefully with a garden fork. Loosen a wide radius around the crown — you’re selecting roots that radiate from the base, not the deep taproot itself.
2. Select pencil-thick roots close to the crown. Choose firm, white or cream-coloured sections and avoid anything soft, brown, or damaged. Remove no more than one-third of the root system to protect the parent plant.
3. Make a straight horizontal cut at the top — the proximal end, closest to the crown. This is where the new shoot will emerge. The straight cut identifies it later, when all sections look identical.
4. Make an angled cut at the bottom — the distal end, farthest from the crown. The angle identifies the bottom at planting time and helps surface water run off the cut face rather than pooling on it.
5. Cut sections 3–5 inches (8–12 cm) long, maintaining the straight/angled system throughout. Each section becomes one cutting.
6. Insert vertically into gritty compost with the straight-cut end at the top, just below the compost surface — no more than ½ inch (1 cm) deep. The angled end points down.
7. Top-dress with grit or perlite to reduce surface moisture around the emerging shoot tip.

For thin-rooted plants (phlox, Japanese anemone, primula, globe thistle, Joe Pye weed)

1. Lift the plant and select thin root sections from the outer root zone, usually 2–4 mm diameter — finer than a pencil.
2. Cut into 2–3 inch (5–8 cm) sections. Polarity still applies, but thin roots can produce shoots from multiple points along their length, so orientation is less critical than with thick roots. Cut consistently so you know which end is which.
3. Lay horizontally about ½ inch (1 cm) deep in trays of gritty compost, spacing sections 1–1½ inches apart. A single tray holds a dozen cuttings.
4. Cover with ½–1 inch (1–2 cm) of fine compost and water lightly. No plastic covering needed — cold frame conditions are sufficient.

Both types go into a cold frame or cool, frost-free indoor spot — ideally 40–50°F (4–10°C). Most perennial root cuttings don’t need warmth to initiate; they need consistent cold to stay dormant until spring triggers growth. A heated propagator forces shoot growth before the cutting has developed enough root tissue to sustain it.

The Right-Way-Up Rule: Why It Matters

Every root cutting guide tells you to plant sections right-way-up. The straight-cut-at-top, angled-cut-at-bottom system exists to stop you mixing up the ends after taking several cuttings. But why does orientation matter so much?

The answer is in the auxin polarity that root tissues maintain even after separation from the parent plant. In an intact plant, auxin (IAA — indole-3-acetic acid) moves basipetally: downward from shoot tips toward roots. When a root cutting is taken, the pieces retain this directional transport system. Research on polar auxin transport confirms that this directional movement persists in excised tissues and is essential for adventitious structure formation — blocking it sharply reduces success rates.

This polarity has a counterintuitive practical consequence:

• In a stem cutting, the basal end (closest to the roots) produces adventitious roots.
• In a root cutting, the proximal end (closest to the crown) produces the adventitious shoot first — and new feeder roots then develop from that shoot.

The proximal end contains the adventitious bud cells with the shoot-forming program. If you plant a root cutting upside-down, those bud cells are at the bottom of the pot, and the new shoot must travel downward against its own auxin transport before it can reverse direction and head for the surface. Many don’t make it. Some produce contorted, looped shoots that exhaust the cutting’s carbohydrate reserves before emerging.

In dandelion — one of the most studied root-regenerating plants — the proximal end consistently produces the shoot whether the piece is oriented correctly or inverted. But correctly oriented pieces succeed at a substantially higher rate because the shoot forms and emerges without fighting the directional hormone flow.

The straight/angled cut system isn’t just a memory aid. It forces deliberate orientation at every insertion. Cut consistently, plant consistently, label every tray — and you remove the single most common failure point in root cutting propagation.

Aftercare and What to Expect

Root cuttings need very little intervention between planting and emergence. The main risk period is the first few weeks, when the cut root surface is vulnerable to rot before wound callus forms.

Keep the compost moist, not wet. Roots sitting in saturated medium rot before they can initiate growth — and unlike stem cuttings in a humidity dome, root cuttings in a cold frame have no leaves losing water, so they need far less moisture than you might expect. I check at weekly intervals by pushing a finger an inch below the surface at the pot edge: if it still feels cool and barely damp, I leave it alone; only if it feels dry do I add a small amount of water.

Thick-rooted cuttings — oriental poppy, verbascum — typically show the first shoot tips within 6–8 weeks, often by late winter. Thin-rooted types are slower: allow 8–12 weeks for phlox and Japanese anemone, and up to 12–16 weeks for Joe Pye weed and primula denticulata.

When shoots reach 2–3 inches tall, gently remove one cutting from the tray and check for new white root threads below. If roots are present, pot individually into 3-inch pots of standard compost. If not, return the cutting and check again in 2–3 weeks. First-year plants from root cuttings are typically small; grow them on in pots through summer and plant out in autumn.

Why Root Cuttings Fail

Root cuttings fail less often from drying out than stem cuttings do, but four specific failure modes account for the vast majority of losses — and most guides don’t address any of them directly.

Planted upside-down. The most common failure, and exactly what the straight/angled cut system is designed to prevent. If 50% or more of a batch produces nothing, check your orientation. Re-examine any you’re uncertain about before inserting.

Taken after bud break. Cuttings taken after spring growth starts have already redirected their carbohydrate reserves toward new shoots. Even if the plant still looks dormant above ground, check whether buds are swelling — if they are, root cuttings this season will have very low success rates. Wait until the following autumn.

Medium too wet. Gritty, free-draining compost is non-negotiable. Root sections rot quickly in standard peat-based mix kept at normal moisture levels. If batches repeatedly fail, the compost is almost certainly the variable. Switch to a 50:50 mix of peat-free compost and perlite, reduce watering to once a week or less, and use a cold frame rather than an enclosed propagator.

Roots too thin or damaged. Sections thinner than 3–4 mm lack the stored energy to generate a viable adventitious shoot. Dark, soft, or damaged sections invite Botrytis or Pythium rot before they can establish. Select only firm, cream-white sections from healthy plants.

If stem cuttings suit the plants you’re working with, or you want to compare the two approaches, see our guide to stem cutting propagation technique.

Frequently Asked Questions

Can you take root cuttings in spring?

You can, but success rates are lower. Once a plant breaks dormancy, its carbohydrate reserves begin redistributing into new shoots. Cuttings taken after this transition have less stored energy and a reduced success rate. The exception is plants that haven’t yet broken dormancy in early spring — if the buds are still fully closed and the soil is just beginning to warm, you’re still within the viable window.

Do root cuttings need rooting hormone?

Most don’t. Root cuttings first develop adventitious shoots, and the root system develops from those shoots — the hormone pathway differs from stem cuttings, which must initiate roots directly from cut stem tissue. That said, echinacea and verbascum show modest improvement with a light dusting of IBA powder on the proximal cut end, particularly for borderline-quality cuttings taken toward the end of the dormant window.

How many root cuttings can I take without harming the parent plant?

The RHS recommends removing no more than one-third of the root system, and taking from several roots across the crown rather than stripping one side. Plants recover well but may show reduced flowering the following season while they rebuild. Verbascum and comfrey tolerate aggressive harvest; echinacea and sea holly benefit from a lighter hand.

Key Takeaways

Root cuttings turn winter dormancy into your most productive propagation window. The biology that explains why — carbohydrates concentrated in dormant roots, auxin polarity maintained in excised pieces — also explains the two rules the technique depends on: take cuttings before carbohydrate reserves deplete, and plant them with the straight-cut end at the top.

Oriental poppy, phlox, and comfrey are the most reliable starting points. For echinacea and sea holly, take five to eight cuttings per species to allow for the few that won’t establish. Label every tray the moment you fill it — by February, every root section in the cold frame will look identical.

Sources

• Root Cuttings — Royal Horticultural Society (rhs.org.uk/propagation/root-cuttings)
• Garden Tip 89 — University of Washington Horticulture Library
• 13. Propagation — NC State Extension Gardener’s Handbook (content.ces.ncsu.edu/extension-gardener-handbook/13-propagation)
• Grow More Plants with Root Cuttings — Fine Gardening
• Plant Hormone Homeostasis, Signaling, and Function during Adventitious Root Formation in Cuttings — PMC / Frontiers in Plant Science (pmc.ncbi.nlm.nih.gov/articles/PMC4814496/)
• 45 Plants to Propagate From Root Cuttings in Winter — Blooming Backyard