Why You Should Divide Your Rhubarb Plants
Mature rhubarb plants, while a joy to behold and harvest from, can eventually become overgrown and less productive. Dividing your rhubarb plants is a fundamental horticultural practice that directly addresses these issues. It is not merely about increasing the number of plants you possess; it is a crucial step in maintaining the health, vigour, and yield of your existing rhubarb patch. When a rhubarb crown becomes too large, its energy is often spent competing with itself for resources such as water, nutrients, and light. This competition can lead to weaker growth and smaller, fewer leaf stalks. Division effectively resets this process, giving each new section a fresh start with ample resources.
The benefits of dividing rhubarb are manifold. Firstly, it rejuvenates older plants. A crown that has been in the same spot for many years may start to show signs of decline, with the centre becoming woody and less fertile while the outer edges remain more vigorous. Division allows you to separate these vigorous outer sections, discarding the less productive central mass, and planting the younger, more energetic parts. This practice can extend the productive life of a rhubarb patch by many years. Secondly, division is a primary method of rhubarb propagation. If you wish to establish new rhubarb patches elsewhere in the garden, or share plants with friends and neighbours, dividing an existing plant is the most straightforward and effective way to achieve this. Each healthy section can develop into a new, fully established plant.
Furthermore, dividing your rhubarb plants can also help to mitigate certain pest and disease issues. Overcrowded plants are more susceptible to fungal infections and can harbour pests more readily. By ensuring adequate space between crowns, you improve air circulation, which is critical for preventing diseases like leaf spot. It also makes it easier to spot and deal with any problems that do arise. For gardeners looking to maintain a consistently high yield of tender, well-flavoured stalks, regular division is an investment that pays dividends. It is a proactive approach to garden management that ensures your rhubarb patch remains a source of culinary delight for years to come.
- Rejuvenates overgrown and declining rhubarb crowns.
- Promotes stronger growth and larger, more numerous leaf stalks.
- Provides an effective method for propagating new plants.
- Improves air circulation, reducing disease risk.
- Extends the productive lifespan of a rhubarb patch.
When is the Optimal Time to Divide Rhubarb?
Timing is perhaps the most critical factor for success when you divide rhubarb plants. While rhubarb is a hardy perennial, undertaking division at the wrong time can stress the plant, hinder its recovery, and negatively impact its performance in the following growing season. The generally accepted best times for dividing rhubarb are either in early spring or in autumn. Each period offers distinct advantages, but both require careful consideration of the plant’s condition and the prevailing weather.
Dividing in early spring, typically as soon as the ground can be worked and before the new season’s growth becomes too vigorous, is often favoured by many gardeners. This period, usually from February to April depending on your local climate, allows the plant to establish itself quickly in its new position using the increasing soil warmth and moisture. The plant’s energy is directed towards root development and unfurling new leaves, meaning it can recover and start producing edible stalks relatively soon. However, care must be taken not to disturb the plant too early, as it is still relatively dormant. You want to divide it before the shoots are more than a few inches tall. If you divide too late in spring, you risk damaging the burgeoning shoots and reducing the harvest for that year.
Autumn, from September to October, is the other prime window for dividing rhubarb. As the plant begins to wind down its growth for the year and store energy in its roots, division can be undertaken. This allows the divided sections ample time to establish their root systems before the ground freezes, without the immediate demand of producing a large flush of leaf stalks. The cooler, moister conditions of autumn are generally conducive to root establishment. A key advantage of autumn division is that it minimally impacts the harvest, as the main harvesting period is already over. However, it is vital to ensure the divisions are well-watered and mulched if exceptionally dry or cold weather is expected during the autumn and early winter, as young, newly divided plants are more vulnerable to frost heave and desiccation.
How to Divide Rhubarb Plants: A Step-by-Step Process
The process of dividing rhubarb plants is straightforward, requiring minimal tools and a methodical approach. The objective is to separate the large, established crown into smaller sections, each possessing at least one or two viable buds (also known as 'eyes') and a good portion of healthy root. Before you begin, ensure you have a sharp spade or a sturdy garden fork, a bucket or barrow for moving the divisions, and possibly some compost or well-rotted manure for replanting.
Preparing the Rhubarb Crown
Begin by cutting back any existing leaf stalks to about 6 inches above the crown. This makes the plant easier to handle and reduces the risk of damaging the delicate buds. If you are dividing in spring, you might be cutting back old, dead material from the previous year. If dividing in autumn, you'll be cutting back the last of the season's growth. Once the stalks are trimmed, you need to carefully excavate the crown. Using your spade or fork, dig around the perimeter of the plant, going about 6-12 inches out from the centre. Work your way down to loosen the entire root ball from the soil. Gently lift the entire clump from the ground.
Splitting the Crown
With the clump out of the ground, you can now see the crown more clearly. It will likely be a dense, woody mass with buds on top and a tangle of fleshy roots below. The first step in splitting is to remove as much soil as possible from the roots. You can do this by shaking the clump or gently washing it with a hose if necessary. This will reveal the natural divisions within the crown and help you identify healthy buds and roots. Many established crowns can be split by hand, especially if they have been divided before or are not excessively old. Look for natural fissures or weaker points.
If the crown is particularly tough and woody, a sharp spade or a strong, clean knife can be used to cut through it. Insert the spade or knife into the crown, aiming to divide it into sections, ensuring each section has at least one strong bud and a healthy root system. Avoid using a blunt tool, as this can crush the tissues and promote rot. Aim for divisions that are roughly the size of a large fist or slightly smaller. Discard any parts of the crown that appear rotten, diseased, or completely devoid of buds.
Ensure each division has at least one healthy, plump bud and a substantial amount of root to maximise its chances of successful establishment.
Replanting the Divisions
Once you have your healthy divisions, it is time to replant them. Choose a new location that receives full sun to partial shade and has fertile, well-drained soil. Dig a hole large enough to accommodate the roots comfortably. Incorporate plenty of compost or well-rotted manure into the planting hole to provide nutrients and improve soil structure. Place the rhubarb division into the hole so that the bud(s) are just at or slightly below soil level. Planting too deep can lead to rot and poor growth.
If replanting multiple divisions, space them adequately, usually about 3-4 feet apart, to allow for future growth. After planting, water thoroughly. If you have divided in autumn, apply a layer of mulch around the base of the newly planted divisions – straw, compost, or leaf mould are good options. This will help retain moisture, suppress weeds, and offer protection against the cold. If dividing in spring, regular watering is essential as the plant begins to grow, but avoid over-saturation.
Caring for Newly Divided Rhubarb Plants
The period immediately following division is critical for the successful establishment of your new rhubarb plants. While rhubarb is notoriously resilient, providing attentive care during this phase will significantly improve their chances of thriving and producing well in their first year, and for many years to come. The primary focus should be on ensuring adequate moisture, protection, and nutrition.
Watering and Mulching
Newly divided plants, especially those planted in spring, will require consistent watering. The fleshy roots need moisture to establish, and the developing leaves will also transpire water. Aim to keep the soil consistently moist but not waterlogged. Check the soil moisture regularly by pushing your finger a few inches down; if it feels dry, it is time to water. Overwatering, particularly in poorly drained soil, can lead to root rot, which is a serious threat to young divisions. A good layer of mulch, such as compost, well-rotted manure, or straw, applied around the base of the plant (keeping it a little away from the direct stem) is highly beneficial. Mulch helps to conserve soil moisture, suppress weed growth, and regulate soil temperature.
The most crucial element for newly divided rhubarb is consistent moisture, especially during the first few weeks after planting.
Feeding and Fertilising
While the compost added to the planting hole provides an initial nutrient boost, you should consider a gentle feeding regime for your young plants. For spring divisions, once new growth is clearly visible and the plant is actively growing, you can apply a balanced liquid feed or a top dressing of compost around the base. Avoid using strong, concentrated chemical fertilisers too early, as these can scorch the delicate young roots. If you divided in autumn, the plant will naturally be slowing down, and heavy feeding is not required. A good mulch applied in autumn will break down over winter, providing nutrients in spring.
What to Expect in the First Year
It is important to manage expectations for the first year after dividing and replanting rhubarb. While some plants may produce a small number of edible stalks, it is generally advisable to be conservative with harvesting. The plant is still investing its energy into establishing a strong root system and crown. Removing too many leaf stalks can deplete its reserves and hinder its long-term development. A good rule of thumb is to remove no more than one-third of the new growth in the first year, or even better, to refrain from harvesting altogether and allow the plant to focus solely on growth. This initial period of restraint will pay off with significantly more bountiful harvests in subsequent years. For those who have divided blueberry bush or grape vine, similar patience is often rewarded with stronger future yields.
Alternatives to Dividing Rhubarb
While dividing rhubarb plants is a highly recommended practice for maintaining and propagating your plants, gardeners might consider alternatives based on their specific needs, the condition of their existing plants, or their overall gardening philosophy. Understanding these alternatives can help you make informed decisions about your rhubarb patch.
1. Allowing Plants to Mature (and Potential Downsides)
The most obvious alternative to dividing is to simply leave your rhubarb plants undisturbed. Rhubarb is a long-lived perennial and can continue to produce for many years, often a decade or more, without division. If your plant is still relatively young (under 5-7 years old) and is performing well, with good-sized stalks and consistent yields, there may be no immediate need to divide. However, eventually, even well-managed plants will benefit from division. Leaving them too long can result in a plant that becomes increasingly woody in the centre, produces fewer and thinner stalks, and may become more susceptible to environmental stress and diseases. The quality of the stalks can also diminish, becoming stringier and less tender. This is not a sustainable long-term strategy for peak productivity.
2. Starting New Plants from Seed
Rhubarb can be grown from seed, which is an alternative method of propagation. However, this approach differs significantly from division. Growing from seed is typically used by commercial growers or dedicated enthusiasts who want to experiment with new varieties or are not concerned with producing plants identical to the parent. This is because rhubarb grown from seed is not true to type; the resulting plants can vary greatly in vigour, flavour, colour, and disease resistance. You might end up with a plant that is excellent, or one that is quite inferior. If you want to ensure you get plants with the same characteristics as your current successful variety, starting from seed is not the way to go. It is also a much slower process, taking several years for a seedling to reach a size where it can be harvested reliably, compared to the relatively quick establishment of a divided crown.
3. Purchasing New Plants
For gardeners who wish to expand their rhubarb patch or replace an old plant, purchasing new plants from a reputable nursery or garden centre is a direct alternative to dividing existing ones. You can buy crowns or young plants, which have the advantage of being disease-free and of a known variety. This is a good option if your current plants are not performing well, or if you want to introduce a different type of rhubarb, perhaps one known for its specific culinary uses or ornamental appeal. However, this does not help you propagate from your *own* existing, successful plants, and involves an ongoing cost.
For those who enjoy cultivating fruit and other perennials, understanding propagation techniques is valuable. Just as pruning raspberries or pruning grape vines requires specific timing and methods to encourage fruit production, dividing rhubarb is about managing the plant's life cycle to maintain its vigour and yield. While starting from seed or buying new plants are valid approaches, dividing is often the most rewarding and cost-effective method for the home gardener who already has a thriving rhubarb plant.
Frequently Asked Questions About Dividing Rhubarb
Here we address common queries regarding the division of rhubarb plants, offering concise answers to help you manage your rhubarb patch effectively.
How to divide rhubarb plants?
To divide rhubarb plants, first cut back the foliage. Then, carefully excavate the entire crown. Split the dense crown into sections using a sharp spade or knife, ensuring each section has at least one viable bud and a healthy root system. Replant these divisions in well-prepared soil, spacing them adequately. Water thoroughly and mulch.
What is the best time of year to divide rhubarb?
The ideal times to divide rhubarb plants are early spring, as soon as the ground can be worked but before strong growth begins, or in autumn, typically September to October. Spring division allows for quicker establishment before summer, while autumn division minimises harvest interruption and allows roots to establish before winter.
Can I divide a rhubarb plant into just one or two pieces?
Yes, you can divide a rhubarb plant into one or two pieces, particularly if the plant is not yet very old or large. The key is that each division must contain at least one healthy, plump bud (eye) and a substantial root system. Smaller divisions with fewer buds may take longer to establish but can still grow into productive plants.