One of first vegetables of the season to produce a harvestable crop, rhubarb has a long and colorful history. Prized for some 5,000 years as a potent medicinal plant in its native China, rhubarb’s purgative powers were thought to protect patients from a wide range of ills, from fevers to energetic imbalances. It’s even credited with saving the lives of several emperors!
Various species of rhubarb (Rheum) became valued medicinals in medieval Europe. But the tart and tasty species of rhubarb we enjoy today (R. rhabarbarum) wasn’t fully embraced as a European vegetable crop until the late 1700s. Rhubarb soon migrated to American kitchens, where it rapidly achieved star status in New England’s produce markets and became fondly known as pie plant.
Rhubarb traveled across the North American continent with the settlers, adapting well to many climates and soil conditions along the way. In the rugged western territories, rhubarb proved its worth beyond the culinary and medicinal. Rhubarb’s below ground rhizomes (horizontal stems) and roots can be used to make dye in delicate green and yellow hues, and the leafstalks make a soft, pretty pink that surely brought a touch of beauty to many a rough pioneer home.
Today, this lush and lovely perennial flourishes in gardens from Maine to Oregon. Practically pest and disease free, rhubarb does best where winter soil temperatures regularly drop below 40°F and summer temperatures rarely reach the 80s. It’s among the most beautiful of edible plants; rhubarb’s huge, ruffled leaves and statuesque greenish-white to rose-red flower plumes make it a great candidate for the floral border. Just bear in mind that rhubarb needs plenty of room—the spreading foliage of a single plant can cover a square yard of soil by May.
Like most vegetables, rhubarb thrives in fertile, humus-rich soil, and it appreciates an annual mulch of mature compost and an occasional top dressing of kelp meal. To promote early cropping, give rhubarb a spot that receives full sun for eight to ten hours a day. Though extremely drought tolerant once established, rhubarb produces the most succulent stalks when it receives regular moisture during its active growing season. To direct rhubarb’s energies to the edible portions of the plant, remove flower stalks as they appear.
Garden centers and catalogs offer numerous edible rhubarb varieties, of which I prefer the green-stemmed ‘Victoria’ and red-stemmed ‘MacDonald’. To enjoy your own, plant dormant rhubarb crowns (rhizomes with leaf buds) in early spring, as soon as the ground can be worked, or in fall, adding a deep mulch of shredded leaves or chopped straw where winters are severe. Fork the bed well, digging in generous amounts of mature compost and loosening the soil deeply. Set each crown so that the rhizomes are below grade, with the leaf shoots at grade, then backfill the planting hole firmly and water well to eliminate air pockets that can cause root rot.
Since great roots are the key to plant sustainability, promote sturdy root growth by scratching in a handful of balanced fertilizer (such as NPK 5-5-5) in spring and a dose or two of liquid kelp in early summer. Young plants need time to develop strong rhizomes and root systems, so don’t harvest the leafstalks for a year or two. Your first harvest should remove no more than a third of the stalks, and even on a mature plant, always leave at least half the stalks to allow the plant to replenish its roots. (Overharvesting is indicated when new stalks remain skinny.)
Mature plants can be harvested from early spring to midsummer in temperate climates. Old-time gardeners insist that rhubarb leafstalks should be pulled, not cut: Grab the stalk near the ground and give a slight twist of the wrist as you tug. Trim off the inedible foliage and add it to the compost heap, where the oxalic acid that makes the leaves toxic (and medicinally active) will quickly break down into valuable nutrients. The plump stems will be very welcome in the kitchen, where their tart, lemony flavor adds zip to traditional desserts, chutneys, and savory sauces—as well as sophisticated entrees. Diced rhubarb adds a lovely sour tang to chicken or hot-and-sour soups and partners splendidly with fish or pork.