Garden Guru: Rhubarb has gone from ancient medicine to pie
CHARLESTON, W.Va. -- Used by the ancient Chinese as medicine and prized as food and medicine by Europeans, rhubarb is a plant that is undergoing a resurgence in popularity.
The tasty perennial is at home in both the vegetable garden and in the landscape bed. The quintessential American rhubarb dish is pie, to which some cooks add strawberries (a sacrilege to rhubarb purists such as myself), but the herbaceous jewel is branching out into other culinary pursuits these days.
The earliest records of rhubarb date to 2700 B.C. in China, where the root of a closely related relative was praised for its purgative qualities (this requires no further explanation). Marco Polo is credited by some with bringing the curative Chinese rhubarb to the West in the 13th century, and numerous Chinese emperors are said to have banned its trade to the West over the centuries.
The genus name Rheum is derived, some say, from Rha, the ancient name of the Volga River, where it grows wild. Others credit the name to the Greek "rheo," meaning "to flow" -- a reference to the aforementioned purgative qualities.
Rheum rhabarbarum, the culinary rhubarb we enjoy today was first recorded in Europe a few years after the Revolutionary War, with its first recorded use as a filling for tarts, which shows that old habits do indeed die hard. Most records indicate that a New England gardener brought seeds or roots to America between 1790 and 1800, but some sources also cite the well-traveled Benjamin Franklin as the first who brought the plant to us.
Rhubarb is a member of the Polygonaceae family, along with buckwheat, sorrel, dock, smartweed and the reviled noxious Japanese knotweed. The edible part of the plant is the stalk, which is the petiole of the leaf. The leaves do contain high levels of oxalic acid, which can cause weakness, nausea, gastrointestinal issues, kidney damage and even coma and death (though sources say you would have to eat more than 10 pounds of leaves for a fatal effect).
The presence of oxalic acid in the leaves makes the plant unpalatable to deer. It is present in small amounts in the stalks as well, which accounts for the tart flavor of rhubarb. The level in the stalks is far below the amount needed to induce illness, but it would be wise not to eat too much (recall that purgative effect we discussed earlier).
There are several varieties available to home gardeners, including the red-stalked Crimson Red, Canada Red, McDonald and Valentine varieties and the green-stalked Victoria variety. Plants can be started from divisions or from seeds, but all rhubarbs are hybrids and seed-started plants might not resemble the parents. Plants prefer well-drained soil high in organic matter with a pH ranging between 5.5 and 6.5 and should be planted in full sun. Remove flower stalks as they develop to keep the plant strong and healthy.
Rhubarb shouldn't be harvested until the second year, with a full harvest waiting for its fourth year. To harvest, grab stalks at the base of the leaf and pull sideways or cut at the base. You can harvest up to two-thirds of a mature plant at one time, and I have heard that you should stop harvesting for the year when the stalks get no bigger than your pinkie finger.
The plant is relatively care-free, with only some minor insects and diseases to worry about. The rhubarb curculio is a weevil that can damage plants, along with some borers, but damage is rare. Possible diseases of rhubarb include fungal leaf spot and crown rot, but proper plant spacing, watering and soil draining make problems rare. I have had issues with slugs dining on rhubarb leaves in the past, but I do have an overabundance of giant slugs in my landscape. As long as they leave the tasty stalks alone for my pie, we can live in peace.
I found the following super-simple recipe for rhubarb pie, and it has now become my standard for summer potlucks. The secret of this recipe is that you put a layer of sugar around the rhubarb, which caramelizes in the oven and keeps the crust crisp and flaky. I get rave reviews about the pie and my flaky pie crust recipe (which I unroll from a box -- shhh).
Fresh Rhubarb Pie
4 cups chopped rhubarb stalks
1 1/3 cups white sugar
6 tablespoons all-purpose flour
1 tablespoon butter
Your favorite double pie crust "recipe"
HEAT oven to 450°.
COMBINE sugar and flour. Sprinkle 1/4 of the mixture evenly in the bottom of the pie crust in the pan. Heap the rhubarb on top of the mixture and cover the heap with the remaining sugar/flour mixture. Dot with small pieces of butter and cover with top crust.
PLACE pie on lowest oven rack and bake for 15 minutes. Reduce oven temperature to 350° and bake an additional 40 to 45 minutes. Serve warm or cold.
John Porter is the WVU Extension Service agent for agriculture and natural resources in Kanawha County. He may be reached at firstname.lastname@example.org or at 304-720-9573. Twitter: @WVUgardenguru.