We have completed another bare root plant sale and distribution and I am surprised so many gardeners are starting or adding to a rhubarb patch. I am surprised because established rhubarb patches can last many years if taken care of, and rhubarb is like asparagus in that you either like it or you don’t; there aren’t many people who are indifferent about rhubarb.
Rhubarb should be planted in an area where it receives full sun, and where the soil is well drained. Most gardeners plant it at the edge of their gardens. The area should be worked up so the soil is loose for a depth of at least two feet. Add in plenty of garden or kitchen compost or composed manure to increase organic matter. The soil pH is not as important with rhubarb; acidic, neutral or alkaline soil can support a good crop.
Established rhubarb plants will become quite large, so each plant should be allowed a three-square-foot area. Plant it early in the spring. Since the roots are fleshy with buds, or eyes, plant the eyes two inches below the soil surface. Proper watering will enhance good production and growth. Soak the soil thoroughly once a week to a depth of one inch during the growing season.
Rhubarb plants are often acquired from another gardener who is dividing his or her patch. If you do get plants from someone, be sure they are healthy so you are not planting diseased plants in your patch. I often tell the story that we bought a potted rhubarb plant from Ralph Peterson when he had the nursery in Lindstrom many years ago. I planted it in the shade and too close to a building. It sat there for a few years and did nothing. Finally, I dug it up, took an ax and chopped it up into eight pieces. I planted those pieces into what is now a healthy rhubarb patch. My only mistake was that I planted the pieces too close together. If your old patch is not doing well, you may want to replace at least part of it every so often.
Insects are not generally a problem, but if rhubarb curculio or stalk borers are eating holes into the crown and stalks, they may be managed by controlling the weeds around the patch, especially the weed curly docks, which carries a virus that occasionally infects rhubarb and causes abnormal growth, loss of vigor or unusual leaf coloration. If the plant appears to be infected with a virus, it’s best to remove it from the garden and start over.
Rhubarb plants require a lot of organic matter and large amounts of balanced complete fertilizer. Top dress with a well-rotted manure in the fall. In the spring an early application of organic matter will give the plant a jump-start.
Don’t harvest new plantings for two years, as it will weaken the plant. To prevent injury to the plant, pull the stalks rather than cutting them. Eat only the stalks, as the leaves contain oxalic acid, which is toxic. They are not deadly but can make you quite sick.