Rhubarb, a popular garden perennial, is recognized for its tart, edible stalks. While botanically a vegetable, it is frequently used in desserts, much like a fruit. Effective plant management, including specific techniques for pruning and harvesting, is important for ensuring its continued health and productivity. This guidance helps maintain the plant’s vigor and encourages a consistent yield of desirable stalks.
Why and When to Prune Rhubarb
Pruning rhubarb redirects the plant’s energy into producing more robust stalks. A primary reason to prune is removing flower stalks, or “bolting.” When rhubarb flowers, the plant diverts energy to seed production, resulting in smaller, less flavorful stalks. Removing these stalks as they emerge ensures the plant focuses resources on desired stems.
Pruning also involves cutting back yellowing, damaged, or diseased leaves. This improves air circulation, helping prevent fungal issues like rust and crown rot. Removing these leaves also eliminates potential hiding spots for pests such as slugs and snails.
How to Prune Rhubarb
Remove flower stalks as soon as they are visible. Use clean, sharp pruners or a knife to cut the stalk close to the crown. An angled cut helps prevent water collection, reducing rot and disease risk.
For yellowing, damaged, or diseased leaves, trim them close to the crown without harming new growth. Always use clean, sharp tools for precise cuts, promoting faster healing and lessening disease entry.
Harvesting Rhubarb Properly
Harvesting rhubarb stalks involves twisting and pulling them at their base. This technique allows the stalk to separate cleanly, minimizing the risk of leaving stubs that could rot or attract pests. Cutting stalks with a knife is discouraged, as it can create an open wound susceptible to infection.
Rhubarb stalks are ready for harvest when they are 10 to 18 inches long and at least 0.75 inches in diameter. The harvesting season runs from April or May through late June or early July, depending on the climate and variety. Rhubarb leaves contain high levels of oxalic acid and are toxic; therefore, they should be removed and discarded immediately after harvesting the stalks.
Caring for Rhubarb After Pruning and Harvesting
After pruning and harvesting, provide appropriate care for plant recovery and future growth. Ensure adequate watering, especially during dry periods, to support energy replenishment. A light application of balanced fertilizer can be beneficial if the soil lacks nutrients, applied in early spring and after the main harvest.
Regularly monitor the plants for any signs of pests or diseases, such as leaf spots or unusual wilting. Addressing these issues promptly can prevent them from significantly impacting the plant’s health. For plants in their first year after planting, avoid harvesting any stalks to allow the root system to become well-established. In the second year, harvest sparingly, taking only a few stalks to further support the plant’s development.