Optimal Timing: Spring or Autumn Planting
Deciding when to plant rhubarb crowns is crucial for establishing strong, productive plants. The two primary windows for planting are early spring and autumn. Both seasons offer distinct advantages, and your choice can depend on your local climate and the specific condition of the crowns you've acquired.
The most common and often recommended time to plant is in early spring, typically from March to April in the UK. This period is ideal because the ground is beginning to warm, but the plants are still dormant. Planting now allows the rhubarb crowns to establish an extensive root system throughout the warmer months before facing the potentially harsh conditions of winter. You'll be looking for the soil to be workable – not waterlogged or frozen. This timing generally gives you a head start for the growing season.
An alternative, and equally viable, planting season is autumn, usually between October and November. This is particularly beneficial in milder climates. Planting in autumn allows the root system to develop slowly over winter, benefiting from natural moisture. By the time spring arrives, the plant is already well-established and ready to put on significant growth. Autumn planting can sometimes lead to earlier harvests in the following year compared to spring-planted crowns.
Consider the state of your rhubarb crowns. If they are bare-root, spring planting is often preferred as it gives them immediate access to the growing season's energy. Container-grown crowns can be planted in either season, but ensure they are well-watered if planting outside the typical spring/autumn windows.
The choice between spring and autumn planting hinges on balancing root establishment with avoiding extreme temperature stress.
Preparing Your Planting Site
Before you even think about the exact date, preparing the planting site is paramount. Rhubarb is a long-lived perennial, meaning it will occupy its spot for many years. Therefore, selecting the right location and amending the soil is a non-negotiable step. Choose a spot that receives at least six hours of sunlight per day, though it can tolerate some partial shade. The soil should be fertile, well-drained, and rich in organic matter. Rhubarb thrives in a pH range of 6.0 to 7.0.
Begin by digging over the planting area to a depth of at least 30-45 cm. Incorporate generous amounts of well-rotted compost or manure. This organic matter will improve soil structure, enhance drainage, and provide essential nutrients. Avoid planting in areas that tend to waterlog, as this can lead to root rot. If your soil is heavy clay, consider adding grit or sand to improve drainage. For sandy soils, extra compost will help retain moisture and nutrients.
Dig your planting hole significantly larger and deeper than the root ball of your rhubarb crown to ensure the roots have ample space to spread out initially.
How to Plant Rhubarb Crowns
What is the best way to physically get your rhubarb crowns into the ground? The process is straightforward but requires attention to detail to give your plant the best start. Whether you're planting in spring or autumn, the technique remains largely the same.
Begin by soaking bare-root crowns in water for a few hours before planting, especially if they appear dry. This rehydrates the roots. If you've purchased container-grown rhubarb, ensure the soil in the pot is moist.
Dig a hole that is wide and deep enough to accommodate the root system comfortably. A common mistake is to plant too deep. The buds, which are small reddish points on top of the crown, should be just visible at or slightly above soil level after planting. Planting too deep can lead to the crown rotting or failing to establish properly. The roots should spread out downwards and outwards.
Position the crown in the hole, ensuring the buds are pointing upwards. Backfill the hole with the amended soil, firming it gently around the crown to eliminate air pockets. Water thoroughly after planting, regardless of the season. This settles the soil and ensures good contact between the roots and the earth.
Ensure the growing buds are positioned correctly at or just below the soil surface for optimal growth.
Spacing and Companion Planting
Rhubarb plants grow large and vigorous, so adequate spacing is vital. Plant crowns at least 1 metre (3 feet) apart. This provides enough room for the plant to spread and allows for good air circulation, which helps prevent fungal diseases. It also makes harvesting easier.
While rhubarb is generally self-sufficient, consider companion planting. It doesn't have many negative interactions. Some gardeners find that planting strawberries nearby can deter certain pests. Others plant pollinator-attracting flowers like borage or calendula around the perimeter to encourage beneficial insects, which can also help with other garden plants like blueberry bushes or strawberry plants. Avoid planting too close to heavy feeders like brassicas, which will compete for nutrients. Think about how other plants, like a grape vine or blueberry fruit bush, would benefit from similar sun and soil conditions without overcrowding.
Aftercare and First Harvest Considerations
Once your rhubarb crowns are planted, a little aftercare ensures they thrive. For the first year, the primary goal is to encourage strong root development. This means resisting the temptation to harvest too much, or indeed, any, stems in the first growing season.
Water your newly planted crowns regularly, especially during dry spells, until they are well-established. Once established, rhubarb is relatively drought-tolerant, but consistent moisture during dry periods will support better growth and flavour. Apply a layer of mulch – such as compost, straw, or well-rotted manure – around the base of the plant. This helps retain soil moisture, suppresses weeds, and adds nutrients as it breaks down. Keep the mulch a little away from the crown itself to prevent moisture buildup.
Feed your rhubarb annually in early spring, just as new growth begins. A dressing of well-rotted compost or a balanced fertiliser will provide the nutrients needed for vigorous growth and abundant yields. Avoid high-nitrogen fertilisers late in the season, as this can encourage weak growth that is susceptible to frost damage.
Allowing the plant to establish fully in its first year is paramount for long-term productivity.
When to Harvest
The general rule for rhubarb is to avoid harvesting in the first year after planting, regardless of when you planted it. This allows the plant to focus its energy on building a strong root system. In the second year, you can typically harvest for about 4-6 weeks. From the third year onwards, you can expect a full harvest season, usually lasting 8-10 weeks, typically from spring through to midsummer.
Harvest only when the stems are plump, firm, and have reached a good size – usually 15-30 cm (6-12 inches) long. Look for stems that are not yet too fibrous. To harvest, grasp the stalk near the base and pull upwards with a gentle, steady motion, or use a sharp knife to cut it cleanly at the base. Never pull the entire plant, and always leave enough stems for the plant to continue photosynthesising and storing energy for the following year. Remove any flowering stalks that appear, as these divert energy from stem production.
For the sweetest, least fibrous stems, harvest in the morning after the dew has dried. Avoid harvesting during prolonged dry spells, as the stems can become tougher.
Understanding Rhubarb Crown Varieties and Conditions
While the timing for planting rhubarb crowns is generally consistent, understanding different types of crowns and their conditions can influence your approach. Rhubarb crowns are essentially a dormant, multi-budded root section of a mature plant, ready to be replanted.
You'll typically find bare-root crowns or pot-grown crowns. Bare-root crowns are the most common and economical. They consist of a main root mass with several visible buds. These are best planted in spring or autumn when dormant and require immediate planting or soaking if not planted right away. Pot-grown crowns are usually available throughout the spring and early summer. They are already growing in a pot, making them easier to handle and less susceptible to transplant shock, but they are generally more expensive. These can be planted at almost any time, provided the plant is healthy and the soil is workable, though spring is still ideal for establishment.
The term 'crown' itself refers to the thickened, woody part of the root from which new shoots emerge. A healthy crown will have at least one, but preferably several, plump, reddish buds. Avoid crowns that look dried out, shrivelled, or show signs of disease or pest damage. The size of the crown can vary, but a good, mature crown will typically be about the size of a clenched fist or larger.
The vitality of the buds on the crown is the primary indicator of its potential for successful growth.
Common Rhubarb Varieties and Their Planting Needs
While most rhubarb varieties share similar planting requirements, some are known for their early cropping or specific flavour profiles. Varieties like 'Timperley Early' are bred for early production, meaning they might benefit slightly from the earliest possible spring planting to maximise their early cropping potential. 'Victoria' is a classic, robust variety that performs well across different conditions. 'Glaskins Perpetual' is known for its ability to crop over a longer period and can be more forgiving of slightly less-than-ideal planting times, though still benefits greatly from autumn or early spring planting.
Regardless of the variety, the fundamental principles of planting remain the same: fertile, well-drained soil, adequate sunlight, and proper spacing. The strength of the established root system, supported by good soil and timely planting, is what determines the plant's long-term vigour and yield. While you might see discussions on growing strawberries in pots or pruning raspberries, rhubarb's perennial nature means investing in its initial planting conditions pays dividends for years to come. It's as fundamental to good gardening as ensuring a blueberry bush gets the right soil acidity.