Known for its astonishingly tart stalks, rhubarb is a garden plant that is either loved intensely or vehemently hated. It is cherished in sugar- ladened dishes such as jams, the quintessential strawberry rhubarb pie, and many muffins, crumble, or buckle recipes by gardeners who enjoy the flavor.
If you’re the type to enjoy the tart deliciousness symbolic of summer, growing your own plant is a fantastic way to have fresh stalks available throughout the season. It is a relatively easy plant to grow and doesn’t require much care beyond what is needed by other garden plants.
Rhubarb (Rheum rhabarbarum) is a perennial vegetable grown in USDA zones 3-8. A single plant will survive in your garden for up to 10-15 years. Care needs to be taken to keep it away from pets as the leaves are toxic; people with gout, kidney disorders, and rheumatoid arthritis should avoid eating it because of the oxalic acid in the stalks.
Upwards of 100 different varieties exist, classified as red, green, or speckled (pink). The varieties vary in sourness and the fibrousness of the stalks, but the color does not necessarily affect the flavor. While some gardeners prefer pure red — or types that are predominantly red — for jams and pies, the green varieties grow more vigorously and typically have longer stalks.
Some of the most commonly grown varieties include:
- Cherry Red
- Chipman’s Canada Red
- Crimson Red
- German Wine
- Hardy Tarty
- Holstein’s Bloodred
- Prince Albert
- Riverside Giant
- Timperley Early
Rhubarb is best planted in the spring. The timing depends on what you are starting – seeds, crowns (one-year-old plants), or divisions. Seeds can be started indoors approximately 6 to 8 weeks before the last frost in your area and then transplanted outside about two weeks before the frost-free date. Plant crowns and divisions once the ground is workable.
One of the most important aspects of planting rhubarb is to work the soil well, ensuring it’s full of nutrients and organic matter. Plants like well-drained, deep soil that is full of organic material. A few days before planting, work the soil 24-inches down, adding plenty of compost or aged manure to increase the organic matter content and improve drainage.
Regardless of the type of plant you are starting, it’s critical to ensure the proper plant spacing when they’re put into the ground. Plan for 4 to 6 feet between plants, giving each plant plenty of space for their large leaves. The crown should be planted level with the soil surface or at the same depth as it was growing in the pot.
To achieve the best growth, your plants need to receive plenty of sunlight, adequate amounts of moisture (especially when young), and supplemental fertilizer three times a year. The plants don’t experience much pressure from pests or weeds but plant growth benefits if they don’t have to deal with insects, mollusks, or competition from weeds.
Like your other vegetable plants, rhubarb needs all-day sun or a spot that receives 6 to 8 hours of sunlight daily. Plants do like protection from the hottest part of the afternoon sun but will thrive even if they don’t get any shade. In hot climates, they will tolerate partial shade, but the shade may reduce the yields.
When plants are young, they need at least one to two inches of water weekly, either through rainfall events or watering. When watering, make sure to soak the soil thoroughly, less often to encourage roots to grow downward. Older, established plants are more tolerant of environmental stresses and can withstand short periods of drought.
Due to their fast growth rate, rhubarb plants are considered heavy feeders and need a boost of nutrients three times a year. Before plants break dormancy, apply a balanced fertilizer (10-10-10) to the soil. Provide a 2nd application when the plant begins actively growing later in spring. In the fall, add 4 to 6-inches of compost to the soil around the plant.
The most common pests are aphids, slugs, snails, and spider mites. These pests typically chew holes in the leaves but rarely disturb the stalks. Since the leaves are discarded, many people never treat their plants for insect pests. If pests are a big problem, companion planting is a helpful strategy to keep pests away.
Keeping weeds from competing with your rhubarb plants isn’t tough when you have mature plants because the large leaves shade the soil and prevent many weeds from growing. The first couple of years, when the plants are still small, remove weeds by hand or mechanically. Make sure not to hoe too deeply and damage the roots.
Rhubarb is one of the first garden plants ready for harvest in the spring. When the stalks are at least 10 inches long, pull them firmly downward and away from the crown. Do not cut the stems as this increases the chance of rot. After harvesting a large portion of the plant in spring, pick as needed through the summer.
Growing rhubarb is relatively easy, and it yields an incredible amount of stalks, even if the plant is slightly neglected. Tips and tricks are always appreciated when you’re growing something new in the garden, regardless of your growing experience overall. Adding a couple of the following tips will help your plant thrive and be healthy.
- Mulch generously around plants, keeping the mulch 2 to 3-inches from the base of the plant.
- Do not harvest any stalks in the first growing season, especially if grown from seed.
- Stop picking in late June to let plants store energy for winter.
- Remove seed stalks when they appear to keep energy directed towards stalk growth.
- Dig up and split plants every 3 to 4 years in early spring or late fall when the plants are dormant.
- Remove all plant debris in the fall and cover with 2-4 inches of straw or mulch to prevent winter burn.
The best companion plants are garden veggies, herbs, and ornamentals that naturally deter common garden pests. This is usually done through their pungent odor or natural chemicals they give off. This natural repellant is helpful to keep pests from eating through rhubarb leaves. Just ensure neighboring plants won’t get shaded out by the plant’s large leaves.
There are very few plants that do not get along well with rhubarb, but a couple of well-known plants shouldn’t be planted nearby. Avoid planting them with peas and sunflowers.