University of Minnesota Extension, Stearns County News
May 28, 2014
Source: Beth Berlin, Extension Educator-Horticulture
University of Minnesota Extension
Stearns & Benton Counties
Ready for Rhubarb
By Beth Berlin, University of Minnesota Extension
ST. CLOUD, Minn. (05/21/14) — Fresh rhubarb pie, crisp, or other delicious desserts are a favorite for many. Finally the weather has warmed up enough for the rhubarb plants to start growing vigorously and many are ready for their first harvest. Rhubarb, sometimes called the “pie plant,” is a staple in many gardens that provides an early season crop.
Rhubarb contains high levels of oxalic acid. Too much oxalic acid in the human body can tie up calcium and make it unavailable to the body. However eating rhubarb desserts occasionally will not cause a serious nutrient deficiency. People with gout or a history of kidney stones should consult their physicians before consuming foods like spinach and rhubarb that contain high levels of oxalic acid.
There are several varieties of rhubarb, but most rhubarb can be harvested once the stalks reach 12-15 inches. The stalks of the plant are actually leaf petioles and vary from green to red in color. To harvest rhubarb simply grasp the stalk firmly, pull, and twist. Keep in mind, using a knife may transfer disease from one plant to the next. The leaves are toxic and should be discarded; leaving them on for any length of time can cause wilting of the stalks. If the plant was started from seed, wait until the second season to harvest any stalks.
Rhubarb can be harvested through the end of June, picking as many stalks as desired. After this time period, rhubarb can still be harvested however the plant will need to maintain a good portion of leaves to photosynthesize. Another reason to decrease the amount harvested is because late season stalks become tougher than spring season harvest.
Rhubarb seems to do best in well-drained soils, but is not picky about the pH of the soil. The best growing environment for rhubarb also is a sunny area with rich composted or fertilized soil. Water the plant thoroughly to a depth of one inch a week for good production.
Typically weeds are not an issue within a rhubarb stand once well established, however be sure to remove any weeds, especially curly dock which is a host for rhubarb curculio. Rhubarb curculio is a half to three-quarter inch, dark-colored, snouted beetle that bores holes into the crown and stalks. Rhubarb plants may suffer from root-rotting fungi if in a poorly drained site. The plants may also suffer from leaf spot diseases; simply remove any infected stalks at the time it is noticed and destroy all leaves in the fall. A few viruses impact rhubarb plants, causing abnormal or stunted growth, or unusual leaf color. If it appears your plant has a virus, the best practice is to remove it and replace with a new one.
No matter the time of year, remove the seed stalks of that emerge. This returns the plant’s energy to the edible stalks or the plant’s reserves for next year. Occasionally, seed stalks will appear early in the season and should be removed by twisting and pulling just like other stalks being harvested. Rhubarb can be transplanted or divided very early in the season. As soon as new growth starts use a clean, sharp shovel and split the plant, or dig the entire plant up and divide it with a sharp knife or saw.
The time is here to harvest your rhubarb and enjoy some fresh baked delicious pies, crisps, cakes, and many other tasty treats that this perennial plant provides for us so early in the season.