How to Divide Perennials in Late January for Free New Plants

While most gardeners have put their tools away until spring, professional growers are already reshaping their borders – transforming one weary clump into five strong new plants at no cost.

Why late January is the sweet spot for dividing perennials

Most home gardeners instinctively wait for warmer, sunnier weather before handling plants. That schedule may suit us, but it does not necessarily suit them. For many hardy perennials, late January is actually the gentlest time to lift, move or divide them.

At this point, plants are deeply dormant. Sap has withdrawn, the above-ground growth has died back or disappeared, and roots are functioning only slowly. Moving or splitting a plant now causes much less disruption than doing so while it is directing energy into fresh foliage and flowers.

Working in late January gives new divisions several weeks to heal and produce fresh root tips before spring growth demands kick in.

After a clump has been lifted and divided, minor root wounds begin to callus over and regenerate. When the days lengthen and temperatures become milder, every division is ready to support new shoots instead of using energy to recover from a late spring disturbance.

There is a practical benefit too: winter rainfall usually softens the ground, so it is easier to cut around large clumps and lever them free without breaking away much of the root system.

Which perennials love being split now – and which should be left alone

Mid-winter division does not suit every plant. Concentrate on robust, deciduous perennials that have died back below ground or remain as dry brown stems above the soil. The strongest candidates are clumps established for at least three or four years that are beginning to flower less freely at their centres.

Prime candidates for a January division

• Autumn asters: Left undivided for too long, these can become woody and affected by mildew. Splitting keeps them compact and vigorous.
• Daylilies (Hemerocallis): Their thick, fleshy roots are straightforward to cut and replant, and they recover quickly.
• Phlox paniculata: Mature clumps often flower less well; division promotes fresh, upright growth with plenty of blooms.
• Coreopsis and rudbeckia: These dependable border plants respond well to lifting and division every few years.
• Hostas: Provided the soil is not frozen solid, they can be divided before their “horns” of new growth emerge above the surface.

Perennials that bloom in winter or very early spring require different treatment. They may already be growing actively, or they may simply object to root disturbance.

Avoid dividing hellebores and peonies in particular. Hellebores are preparing to flower, and cutting into them now can reduce the display by half. Peonies can remain unhappy for years if they are moved or divided poorly.

As a rule, if a perennial is already in bud or bloom, or famously hates root disturbance, leave it alone until its resting phase.

Step-by-step: how to split a clump without killing it

The point at which many gardeners lose confidence is after the plant has been lifted, when it is time to make the cut. It can seem harsh. However, division is more like an operation than destruction: it removes exhausted material and provides the healthiest sections with additional space.

Lifting the plant

• Pick a day when the ground is workable rather than frozen hard or saturated with water.
• With a spade or garden fork, dig a wide circle around the clump, keeping a few inches from the visible stems.
• Lift the entire root mass in one piece where possible, preserving as many outer roots as you can.
• Shake away or lightly tap off surplus soil to reveal the root system’s structure.

In most cases, you will find a weary, woody middle with fewer live buds, enclosed by younger and healthier growth. The old central section should be discarded, while the outer parts are the sections to retain.

Making the divisions

Once the clump is lifted, there are two main methods for dividing it.

• By hand: With fibrous, pliable roots, gently but firmly pull the clump into separate sections. Begin at the outside and work inwards.
• With a blade: For tightly tangled crowns, use a sharp spade, pruning saw or strong knife. Put the clump on the ground and slice it into wedge-shaped portions, as if cutting a cake.

Each new piece should have at least one or two visible buds and a decent fan of roots. Tiny scraps rarely thrive.

Do not worry if some roots break during the process. Daylilies, rudbeckias and asters, among other species, tolerate fairly rough treatment provided each final section retains sufficient roots and several growing points.

Replanting: the crucial hour after division

Newly cut roots can dry surprisingly quickly in a winter breeze. Once you have started lifting and dividing, plan to replant every section that same day.

If you can’t plant immediately

• “Heel in” the pieces temporarily in an unused vegetable bed: make a shallow trench, arrange the divisions in it and cover the roots with soil.
• Alternatively, pot them into containers of garden soil or peat-free compost, then place them somewhere sheltered.

Preparing the final planting spot matters just as much as making the divisions.

Step	What to do
1. Improve the soil	Break up the planting area and incorporate well-rotted compost or a slow-release organic fertiliser.
2. Plant at the right depth	Position the division with its crown, where the roots join the shoots, at soil level or very slightly above it.
3. Firm in well	Use your hands or boot to press soil around the roots and eliminate air pockets.
4. Water once	Water thoroughly to settle the soil around the roots, even when rain is expected.

Cold weather remains a possibility, particularly for recently disturbed roots.

A thick mulch of leaves, bark or straw around the base acts like a winter duvet, buffering young roots from hard frost.

Keep mulch slightly clear of the growing points so that they do not rot during extended damp weather.

The quiet maths: how one clump becomes a border

Dividing perennials in late January brings visual, horticultural and financial rewards.

Consider a mature daylily that has occupied the same spot for five years. Above ground, it may appear to be one plant. Beneath the surface, however, it is often a ring of several smaller plants crowded together. Fifteen minutes with a spade can frequently produce five or six substantial divisions.

If each of those divisions would cost £7–£10 at a garden centre, a single session with a spade can save £40 or more.

The less immediately visible benefit is improved plant health. Congested, ageing clumps slowly deplete the soil beneath them and become increasingly susceptible to disease. Dividing them reduces this strain, gives each piece fresh soil and can deliver stronger flowering within a season or two.

There is a design benefit as well. Repeating the same variety at intervals throughout a border unifies the overall scheme. Dividing your own plants allows you to create that rhythm and cohesion without searching shops for identical cultivars.

Common pitfalls and how to avoid them

Most post-division failures result from a small number of straightforward errors.

• Replanting divisions that are too small or lacking in strength.
• Allowing exposed roots to sit in drying wind for hours.
• Planting back into compacted, nutrient-poor soil without adding organic matter.
• Neglecting to water at planting because “it’s winter, the soil is wet”.
• Dividing plants that are not fully dormant or dislike being disturbed, including peonies.

Avoid these mistakes and success rates are generally high, particularly with the robust perennials listed above.

A few useful terms and scenarios for new gardeners

“Dormancy” is a term that appears frequently in winter gardening guidance. Put simply, it is a plant’s resting period. Growth stops above ground, while below the surface its metabolism slows without stopping altogether. This is why roots can still repair themselves and grow gradually after a clump is divided in cold conditions.

Another helpful term is “crown” or “collar”, meaning the point where roots and stems meet. If planted too deeply, the crown can rot; if planted too shallowly, the roots are more vulnerable to drying out or freezing.

Picture two neighbouring gardens this year. In one, the gardener leaves every mature perennial untouched until April. Fresh shoots are already appearing by then, so division checks the plants just when they are spending energy on growth. In the other, the gardener uses a cold Saturday in late January to divide three or four key clumps, replant the strongest pieces and apply mulch.

By midsummer, the second garden usually shows fuller borders, more even flowering and fewer gaps – all for the price of a few hours in the cold.

For beginners, combining winter division with simple composting is a sensible approach. The woody central material removed from old plants need not be wasted; once it decomposes in the compost heap, it contributes to future soil health. Over several seasons, this pattern of dividing, planting and composting can change a sparse, uneven border into a dense, repeated tapestry of colour – without buying a single new plant in spring.