Rhubarb is generally trouble-free. Slow growth of older plants is a signal that they need dividing. Rhubarb curculio—a half-inch long, yellow-gray beetle—damages stalks and crowns by boring holes in which to lay its eggs. Handpick adult curculios and destroy nearby curly dock (Rumex crispus), a weed which is an alternate host for this pest.
You can harvest 2-6 pounds of rhubarb each season from a full-size plant. Cool, moist weather tends to increase productivity, while warm, dry conditions may reduce your harvest.
Havesting & Resources
You may lightly harvest rhubarb one year after planting small divisions or nursery plants. Gradually increase the number of stalks and the length of time you pick in the second and third years of growth. Expect healthy plants to produce fully in the fourth year.
Organic market gardener Molly Bartlett of Silver Creek Farm in Ohio transplants good-size rhubarb divisions in early spring. They produce large, tempting stalks in May, which she harvests lightly without damaging the plants.
Harvest lightly one year after planting. Pick only stems that are at least 1 inch thick the second year; then harvest for one to two months in the third year. Snap off rhubarb stalks by twisting them sharply at the base. Or cut them off with a sharp knife, using care to avoid injuring underground buds. Cut off and compost the leaves as you harvest (don't eat the leaves—they're poisonous). Starting when the leaves are expanding in the spring, you may pick one-third to one-half of the new shoots from a full-size plant. Cool, moist weather encourages plants to produce fat new stalks; keep picking until the stalks that emerge are pencil-thin.
Longtime rhubarb grower Judith Dilkie of Ontario, Canada, harvests a second time in fall when she cleans up the bed for the season. To harvest longer stalks, try putting a bottom-less bushel basket over the plant until the stems reach the desired length; the stems stretch up longer—and stay paler—in the limited light.
What's Good in Rhubarb
1/2 cup diced = 15 calories
0 percent fat
0 percent cholesterol
1 g fiber
1 g protein
What's Not Good in Rhubarb:
The leaves are poisonous. Trim them off and eat only the stalks.
Freezing for later use.
1. Select firm but tender stalks with few fibers. Wash, trim and cut into 1- or 2-inch pieces.
2. Put rhubarb pieces in boiling water for 1 minute to blanch them.
3. Move the blanched rhubarb from the boiling water to cold water. Drain well.
4a.Unsweetened: Pack blanched rhubarb tightly into containers, leaving half-inch headspace. Seal, label and freeze.
4b. Sweetened: Pack blanched rhubarb lightly into containers. Pour cold syrup (1 cup sugar dissolved in 1 cup water) over the rhubarb, leaving a half-inch of headspace. Seal, label and freeze.
Extending the season.
If you have extra rhubarb plants, try forcing one in the winter. In fall, transplant the extra into a tub of moist planting mix or sand. Leave the tub outdoors in 28 to 50 degree F temperatures for 7 to 9 weeks, then move it into cool (55-60 degrees F), bright indoor conditions. Keep the soil moist; stalks will appear in about a month. Harvest when they reach 1 to 1.5 feet long.
Divide large root clumps by slicing them into pieces with a sharp spade, or work the twisted roots apart with your hands. Replant the pieces or share them with a friend.