Horticulture Magazine

How (And When) To Split Rhubarb

green rhubarb foliage

Rhubarb is a useful perennial plant which can be split, or divided easily.

But why might you want to split a mature rhubarb plant? How and when exactly should you contemplate doing so?

In this simple guide we will walk you through the process and show you just how easy it is to split rhubarb plants in your garden.

Why You Might Split Rhubarb

mature rhubarb plants with lots of green foliage in a garden
Mature rhubarb

The first thing to think about if you are considering this process is why you might wish to do so. There are two main reasons why you may wish to split a mature rhubarb plant:

  1. To make new rhubarb plants.
  2. To maintain health and vigour in an existing rhubarb plant or rhubarb patch.

To Propagate New Rhubarb Plants

First of all, you might with to divide your rhubarb to create new rhubarb plants for your garden.

Splitting an existing rhubarb crown is the easiest way to propagate these perennial plants.

The sections which are split away from the mature plant will each grow into a new plant identical to the parent plant from which the division was taken.

The plants you propagate from division of an existing rhubarb plant can be used to fill gaps in your garden, or increase your stocks of this useful perennial edible plant.

You might also consider dividing an existing mature rhubarb plant to give away to family or friends. In a market garden, you might even wish to propagate new rhubarb plants that you can sell.

To Ease Congestion or Aid a Mature Specimen

The second reason to split rhubarb is to overhaul an overly crowded part of your garden. Or to improve the health and productivity of an older specimen.

You might divide a rhubarb plant, replanting only a portion and moving other sections elsewhere. This can be a good idea where a rhubarb has grown large and outstripped the size of the space available for it.

It might be reduced in vigour due to a lack of resources – or it might be competing too much with neighbouring plants and restricting their growth and health.

A mature and large rhubarb plant might also start performing worse over time. Dividing the crown to generate new plants can give old plants like these a new lease of life.

How To Split Rhubarb – Step By Step

rhubarb crowns emerging from the ground in early Spring
Rhubarb crown

First of all, when planning to split rhubarb, it is important to think about where the divisions will be going. If necessary, prepare growing areas suitable for them. Add plenty of organic matter.

Next, using a garden fork, gently lever the crown of the rhubarb plant out of the soil. Take care not to damage the crown, and try to keep as much of the root rhizomes from below the soil as possible.

Carefully split the rhubarb crown into sections, making sure that each section as a shoot and a portion of the root system.

Usually, you should be able to split apart the crown by hand. However, tougher portions may need to be severed with a spade, or with a sharp bladed implement.

If you wish to retain the majority of the mature plant to replace, or if renovating a mature plant, you may wish to simply remove a few small sections around the sides.

If your goal is to maximise propagation and gain as many new plants as possible, you can divide the entirety of the mature crown into smaller sections.

If you are retaining the mature plant, replant this to the same depth in the soil as quickly as possible. If you have a series of new plants to place, you should also do so right away.

The rhubarb crown sections can be replanted in the soil elsewhere in your garden, or placed in pots or containers where they can grow on.

Trim off any dead, trailing foliage from the plants, so that they can concentrate on forming healthy new root systems.

Mulch well with organic matter around the plants placed into the soil, so there is plenty of fertility and to make sure the transplantation goes well and plants experience as little shock as possible.

Go easy on harvesting from the rhubarb divisions (or forgo harvesting altogether) the following season, so the plants get a change to establish properly and can provide you with bigger, better harvests over the following years.

rhubarb root on a garden wooden table
Rhubarb division

When To Split Rhubarb

It is best to split mature rhubarb plants during the dormant period, some time between Autumn and very early spring.

At this point, there will not be much above-ground growth, and the crowns and roots will be easier to lift and divide. Transplantation shock will also be reduced. And the new plant divisions and existing plant can form strong and healthy root systems before the new growth emerges in the spring.

In the UK, November is generally considered to be a good time to split rhubarb plants, though you can also undertake this job throughout the winter where the ground is not waterlogged and remains unfrozen.

You can also, if you wish, choose to wait until early spring so you can see where healthiest new growth is emerging from on the crown.

It is generally recommended that you should split mature rhubarb plants every 4-5 years to keep up productivity and keep the plants healthy and strong.

You may also wish to read our guide on how to force rhubarb and encourage an early crop.

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