Rhubarb crisp, rhubarb jam, rhubarb cake… let me count the ways. Rhubarb is a hardy vegetable that is great for our area, but it also has a dark side. Find out ways to get rhubarb growing in tip top shape and what you need to keep in mind to stay safe.
This vegetable is a tough one. Rhubarb is a standard vegetable that comes back for years if treated right. A perennial plant in the buckwheat family, rhubarb (Rheum rhabarbarum) is native to Siberia and was introduced by European settlers in the 1700s. Rhubarb prefers full sun with well-drained, fertile soil that is high in organic matter. Manure or compost can be incorporated into the soil to increase the organic matter content. There are two common kinds of rhubarb, green stalked varieties and red stalked varieties.
Rhubarb is an interesting plant. The leaf stalk of the plant is edible, while the leaves are not. The leaves are toxic and contain large amounts of oxalic acid which can cause human and animal poisonings including nausea, vomiting, and abdominal pains. The tart leaf petioles, or stalks, can cooked and sweetened to be used in pies, cakes, breads, and a whole range of tasty treats and baked goods. One word of caution with rhubarb. Following a HARD freeze, the oxalic acid in the leaves can migrate from the leaf into the stalk. Do not eat wilted or limp stalks from frostbitten plants. If freeze damage has occurred to the plants, the leaf tissue will appear water soaked or darkened immediately following the freeze. Then they will wilt and eventually dry and turn black around the edges. If there is no evidence of leaf damage, then the stalks are considered safe to eat. When in doubt, remove injured leaves and stalks. Eventually a new set of leaves will emerge that are safe to consume.
Treat the plants well, and they will treat you well. Plants can either be purchased as crowns or divided from existing plantings. Ideally, plant or divide rhubarb roots early in the spring when the plants are still dormant or as they are just starting to emerge. Plant roots with the crown bud two inches below the soil surface and space the roots 36-48” apart in rows 3-4 feet apart. In the first year of establishment, don’t pick from the patch. The second year, pick very sparingly from the patch. The third year you can pick ‘normally’, just be sure not to remove more than 2/3 of the fully developed stalks at one time. Harvest the stalks when they are about 10-15” long and pull the stalk from the base of the plant. Cut the foliage off immediately after harvest and the stalks can be placed in a plastic bag in the refrigerator for up to 4 weeks. Stalks can be harvested on well-established plants until mid-June. Continuing to harvest heavily into the summer months can weaken the plants and reduce yields and the quality of next year’s crop.
Flower stalks are a common occurrence with rhubarb. Flower development is natural. Drought, extreme heat, and infertile soils may encourage flowering. Age is also another factor to consider as older plants tent to flower more than younger ones. When spotted, flower stalks should be removed as soon as possible. Plants can be less productive if they put all of their energy into flower production instead of into stalk and leaf production.
With a little TLC rhubarb can continue to tickle taste buds for years to come.
Elizabeth Killinger is the Horticulture Extension Educator with Nebraska Extension in Hall County. For more information contact Elizabeth at firstname.lastname@example.org, her blog at https://huskerhort.com/, or HuskerHort on Facebook and Twitter.