In this ultimate guide to growing rhubarb, you’ll learn how to plant rhubarb, tips on harvesting rhubarb, and answers to questions like, should I let rhubarb flower? Rhubarb is an easy-to-grow, vibrant addition to any backyard garden & one of our favorite low-maintenance perennials.
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Rhubarb, with its vibrant red stalks and tart flavor, is an easy addition to any garden. Not only does it bring a burst of color to your outdoor space, but it’s also a versatile ingredient for pies, jams, and sauces. If you’ve ever considered growing rhubarb in your garden, you’re in for a treat! In this comprehensive guide, we’ll walk you through the steps to successfully plant, cultivate, & harvest this hardy perennial.
Choosing the Right Rhubarb Variety
Before you start planting rhubarb, it’s essential to choose the right variety for your climate and preferences. Common varieties include Victoria, Canada Red, and Cherry Red. Consider factors such as cold hardiness, disease resistance, and the ultimate size of the plant when making your selection.
Where does rhubarb grow best?
Rhubarb thrives in temperate climates and is best suited to regions with cool, moist summers and cold winters. It is typically grown in USDA hardiness zones 3 to 8, although specific varieties may have slightly different requirements.
This perennial plant requires a period with temperatures below 40 degrees Fahrenheit to stimulate the production of flower stalks and subsequent stem crops. Therefore, regions with long, cold winters are ideal for rhubarb cultivation.
Rhubarb prefers well-drained soil with a slightly acidic to neutral pH and benefits from full sunlight or partial shade, particularly in warmer climates where some shade may help prevent wilting.
Does rhubarb spread?
Yes, rhubarb does have the potential to spread, albeit not aggressively like some other plants. Rhubarb grows from perennial crowns, and over time, these crowns can expand, producing more stalks and increasing the size of the plant. However, rhubarb is not invasive and typically spreads slowly, primarily through division of the crowns.
Proper spacing at planting, regular division every few years, and containment within a designated area can help control the spread of rhubarb in the garden. Additionally, removing any flower stalks that emerge can redirect the plant’s energy towards producing robust stalks rather than setting seeds, which could contribute to its spread. With proper care and management, rhubarb can be a valuable and low-maintenance addition to your garden.
Planting Location and Soil Preparation
Rhubarb thrives in well-drained soil with a slightly acidic to neutral pH. Choose a location that receives full sunlight or partial shade, especially in warmer climates. The soil should be rich in organic matter, so amend it with compost or well-rotted manure before planting.
Where is the best place to plant rhubarb in the garden?
When selecting a spot, consider the size and spread of mature rhubarb plants, which can reach widths of up to four feet. Therefore, ample spacing between plants is crucial to allow for proper growth and air circulation. Also, choose a site that is sheltered from strong winds to prevent damage to the large, leafy stalks.
Consider growing rhubarb near the following plants to maximize benefits.
- Leafy greens like kale, lettuce, or spinach have shallow root systems and can benefit from the deep-rooted structure of rhubarb, which helps improve soil structure and nutrient availability.
- Herbs such as chives, mint, and parsley make excellent companions for rhubarb, as they repel certain pests that may target rhubarb while also attracting beneficial insects like pollinators.
- Legumes like beans fix the soil and provide extra nitrogen, which rhubarb needs a moderate amount of to grow good stalks for harvest
- Perennial flowers like marigolds or lavender, not only add beauty to the garden but also help deter pests with their natural fragrance.
By providing these optimal growing conditions, you can ensure that your rhubarb plants flourish and yield a bountiful harvest season after season.
Learn more about companion planting here.
What should not be planted near rhubarb?
When planning your garden layout, it’s important to consider which plants may not thrive when planted near rhubarb. The main idea is to keep plants that have easily transferrable pests & diseases away from your rhubarb plants.
For example, avoid planting members of the brassica family, such as cabbage, broccoli, and cauliflower, near rhubarb. These plants can potentially attract cabbage root maggots, which may harm the rhubarb roots. It’s also a good idea to keep dock away from your rhubarb. Dock attracts rhubarb curculio – aka snout beetle – that bores into rhubarb crown and stalks.
Similarly, plants susceptible to fungal diseases, like tomatoes, should be placed at a distance from rhubarb to minimize the risk of contamination. By being mindful of these considerations, you can create a harmonious garden environment that promotes healthy rhubarb plants.
Learn more about companion planting here.
Planting Rhubarb Crowns
Rhubarb is typically grown from crowns – as opposed to being grown from seed. “Crowns” are sections of established plants that include both roots and a bud. Plant new rhubarb crowns in early spring or late fall, spacing them about 3 to 4 feet apart to allow for proper growth. Dig a hole large enough to accommodate the crown’s roots and settle it in, ensuring that the bud is just below the soil surface.
Where to Get Rhubarb Crowns
Obtaining rhubarb crowns for your garden is relatively straightforward, and February marks an opportune time for this task, as it coincides with the optimal period for dividing rhubarb plants.
One excellent source for rhubarb crowns is your own garden or that of a gardening friend. If you know someone who already grows rhubarb, consider asking them for a division of their plant’s crown. This method not only ensures that you’re receiving a proven variety that thrives in your local climate but also fosters a sense of community and sharing among gardeners.
Otherwise, local nurseries, garden centers, and online suppliers often carry rhubarb crowns, offering a variety of cultivars suited to different tastes and growing conditions. When selecting rhubarb crowns, prioritize healthy specimens with firm roots and visible buds, as these are indicators of vigorous growth and future productivity in your garden.
What month is best to plant rhubarb?
The optimal time to plant rhubarb is typically in early spring, around March or April, depending on your specific climate and growing zone. Planting rhubarb early in the spring allows the crowns to establish themselves before the onset of hot weather, ensuring robust growth throughout the growing season. Also, planting rhubarb in the spring provides ample time for the plants to develop strong root systems before the dormant winter period.
If you’re dividing existing rhubarb plants, February is an excellent month for this task, as it aligns with the natural growth cycle of rhubarb and allows ample time for the divisions to establish themselves before the growing season kicks into full gear.
Watering and Mulching
Rhubarb plants prefer consistently moist soil, so water them regularly, especially during dry spells. Apply a layer of organic mulch, such as straw or compost, around the base of the plants to retain moisture, suppress weeds, and regulate soil temperature.
While rhubarb is not overly demanding when it comes to nutrients, it benefits from an annual application of balanced fertilizer in early spring. Rhubarb is considered a heavy feeder and can deplete the soil – so it’s important to amend & provide sufficient nitrogen for your rhubarb plants to thrive.
Does rhubarb need a lot of nitrogen?
Rhubarb does not require excessive amounts of nitrogen for optimal growth, but it does benefit from a moderate supply of this essential nutrient. Nitrogen plays a crucial role in promoting lush foliage and healthy plant growth, which is important for rhubarb’s overall vigor and productivity. However, too much nitrogen can encourage excessive leafy growth at the expense of robust stalk development, leading to weaker stems and reduced harvest yields.
So, it’s essential to strike a balance when fertilizing rhubarb, providing enough nitrogen to support healthy foliage while avoiding overstimulation. Incorporating organic amendments such as compost or well-rotted manure can provide a steady, balanced supply of nitrogen, along with other essential nutrients, promoting optimal growth and a bountiful harvest of flavorful rhubarb stalks.
What is the best fertilizer for rhubarb?
The best fertilizer for rhubarb is one that provides a balanced mix of nutrients while also maintaining soil pH levels within the optimal range for rhubarb growth. While rhubarb is not particularly demanding when it comes to fertilization, it benefits from a fertilizer with a balanced NPK (nitrogen, phosphorus, and potassium) ratio, such as a 10-10-10 or 5-10-10 formulation. Also, incorporating organic amendments like compost, aged manure, or well-decomposed leaf mulch can provide a steady supply of nutrients and improve soil structure over time.
It’s important to apply fertilizer sparingly and evenly around the base of the plant, avoiding direct contact with the stalks to prevent burning. A light application of fertilizer in early spring, just as new growth emerges, and another in early summer can help support healthy foliage and robust stalk development, leading to a successful rhubarb harvest. Regular soil testing can also help determine any specific nutrient deficiencies and guide fertilizer application accordingly, ensuring optimal growth and productivity of your rhubarb plants.
Do coffee grounds help rhubarb?
Coffee grounds can be a beneficial addition to the soil around rhubarb plants, providing a source of organic matter and essential nutrients. Rhubarb thrives in soil rich in organic material, and coffee grounds contribute to soil fertility by adding nitrogen, potassium, and other trace minerals. However, it’s essential to use coffee grounds in moderation and ensure they are fully composted or aged before application to avoid nitrogen burn or acidity imbalance in the soil.
Incorporating coffee grounds into the soil around rhubarb plants can improve soil structure, promote microbial activity, and enhance overall plant health. Also, coffee grounds can help deter certain pests, such as slugs and snails, which may damage rhubarb foliage. Overall, while coffee grounds can be a valuable addition to the garden, it’s essential to use them wisely and in conjunction with other organic amendments for optimal results.
Managing Rhubarb Pests and Diseases
Keep an eye out for common pests like aphids and spider mites, and address them promptly with insecticidal soap or neem oil. Rhubarb is relatively resistant to diseases, but good garden hygiene, proper spacing, and adequate air circulation can prevent issues like crown rot and powdery mildew.
What bug is eating my rhubarb leaves?
If you’ve noticed holes or chewed edges on your rhubarb leaves, it’s likely that one of several common garden pests is to blame. One culprit could be the rhubarb curculio, a small weevil that feeds on the edges of rhubarb leaves, leaving behind irregularly shaped holes. Another potential pest is the rhubarb weevil, which similarly damages leaves by feeding on their edges. Also, caterpillars like the cabbage looper or the imported cabbage worm may also feed on rhubarb leaves, leaving behind characteristic chew marks.
To identify the specific pest plaguing your rhubarb, inspect the plants carefully for signs of insect activity, including larvae, eggs, or adult insects. Once identified, you can take appropriate measures to control the infestation, such as hand-picking the pests, applying organic insecticides, or introducing natural predators to the garden. Regular monitoring and prompt action can help protect your rhubarb plants from further damage and ensure a healthy, thriving crop.
Learn more about common garden pests of the PNW here.
What does diseased rhubarb look like?
Diseased rhubarb plants may exhibit a variety of symptoms, ranging from discoloration and wilting to stunted growth and abnormal leaf development.
- Powdery mildew is characterized by a white powdery coating on the leaves, stems, and other plant parts.
- Crown rot causes the rhubarb crowns to become soft, mushy, and discolored, often leading to plant death.
- Bacterial leaf spot manifests as dark lesions or spots on the leaves that gradually enlarge and coalesce.
- Verticillium wilt may display yellowing or wilting of the foliage, often accompanied by stunted growth and reduced vigor.
Proper diagnosis of diseased rhubarb requires careful observation of symptoms and may necessitate laboratory testing or consultation with a plant pathology expert. Once identified, appropriate measures such as removing infected plant parts, improving cultural practices, and applying fungicides or bactericides may help manage the disease and prevent its spread to other plants in the garden. Regular monitoring and proactive disease management are essential for maintaining the health and productivity of rhubarb plants.
Patience is key when it comes to harvesting rhubarb. Allow the plants to establish for at least two years before harvesting, and then selectively pick stalks when they reach a length of 10-15 inches. Grasp the stalk near the base and pull it gently to avoid damaging the crown. It’s also important that you not harvest more than one-third of the plant’s stalks per year, allowing the remaining stalks to continue photosynthesizing and replenishing the plant’s energy reserves.
How do you know when rhubarb is ripe?
Stalk length is the best indicator of ripeness. Typically, rhubarb stalks are ready to be harvested when they reach a length of 10 to 15 inches and are firm to the touch.
Keep in mind that the color of the stalks is not necessarily an indicator of ripeness, as some varieties may remain green or develop a tinge of red regardless of maturity. Instead, focus on the size and texture of the stalks, aiming for those that are thick and crisp.
Does rhubarb grow better if you pick it?
While it may seem counterintuitive, picking rhubarb actually promotes better growth and productivity of the plant. Regular harvesting of rhubarb stalks encourages the plant to produce more stalks, leading to increased yields throughout the growing season. When rhubarb stalks are left on the plant for too long, they can become tough and fibrous, detracting from their flavor and culinary quality.
By harvesting rhubarb promptly when the stalks reach the desired size, you not only ensure tender and flavorful stalks but also stimulate the plant to continue producing new growth. It’s important to harvest rhubarb properly by gently pulling the stalks from the base rather than cutting them, as this helps prevent damage to the crown and encourages regrowth.
Should I let rhubarb flower?
Whether or not to let rhubarb flower is a matter of personal preference and gardening goals. Allowing rhubarb to flower can be visually appealing, as the plants produce tall, slender stalks topped with clusters of small flowers. However, allowing rhubarb to flower can also divert energy away from stalk production, potentially reducing the overall yield of edible rhubarb stalks. Also, once rhubarb plants flower, the stalks may become woody and less palatable.
To maximize the harvest of tender, flavorful rhubarb stalks, many gardeners prefer to remove the flower stalks as soon as they appear, redirecting the plant’s energy towards stalk production instead. If you do choose to let rhubarb flower, consider doing so selectively, allowing only a few stalks to bloom while removing the majority to maintain optimal productivity. Ultimately, the decision to let rhubarb flower depends on your preferences and priorities as a gardener.
How long does it take for rhubarb to produce fruit?
Rhubarb is unique among fruit-bearing plants in that it is primarily cultivated for its tart, crisp stalks rather than its fruit. While rhubarb does produce small, inconspicuous flowers that can eventually develop into seed pods, these seeds are typically sterile and not used for propagation. So rhubarb is usually propagated through the division of the crowns rather than seed propagation.
As a result, gardeners should not expect rhubarb plants to produce significant fruit in the traditional sense. Instead, rhubarb plants are typically grown for their flavorful stalks, which can be harvested for culinary use once the plants are well-established, usually within two to three years of planting. With proper care and maintenance, rhubarb plants can continue to produce abundant harvests of stalks for many years to come, providing a reliable source of tart, tangy goodness for pies, jams, and other culinary delights.
Dividing rhubarb is a key aspect of its care and maintenance, ensuring continued vigor and productivity in the garden. Rhubarb plants tend to become overcrowded over time, leading to decreased yields and smaller stalks. Dividing them every few years helps rejuvenate the plants and prevent overcrowding. The best time to divide rhubarb is in early spring or late fall, when the plants are dormant.
To divide rhubarb, carefully dig up the entire plant, being mindful of the deep root system. Using a sharp knife or shovel, divide the crown into sections, ensuring that each division has at least one healthy bud or “eye” and a portion of the root system. Replant the divisions in prepared soil, spacing them at least 3 to 4 feet apart to allow for future growth. Water the newly divided plants thoroughly and continue to care for them as usual. Dividing rhubarb not only helps maintain plant health but also provides an opportunity to propagate new plants for yourself or fellow gardeners.
Growing rhubarb is a rewarding experience – both adding a statement plant to your garden and enjoying delicious rhubarb treats. By choosing the right variety, providing proper care, and being mindful of pests and diseases, you can enjoy a bountiful rhubarb from your own backyard.
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