Culture
Best grown in fertile, sandy-humusy, slightly acidic, medium moisture, well-drained soils in full sun to part shade. Best grown from root divisions (sections of root with one or more buds or eyes). Plant root sets 3-4' apart in early spring. Do not harvest stalks until the second year. Divide the root crowns every 3-4 years. Needs regular, consistently even moisture. Promptly remove all flower/seed stalks as soon as they appear. Rhubarb generally does best in cooler climates, and tends to decline in summers where average temperatures exceed 75 degrees F. In the deep South, it may be best grown as an annual.
Noteworthy Characteristics
Rheum × hybridum, commonly called rhubarb, is a clump-forming perennial vegetable grown primarily for its edible leaf stalks which are used most often in sauces, jams or pies. Varieties cultivated primarily for cooking fall into the hybrid designation of Rheum x hybridum. This interesting plant typically grows to 3' tall and to 4' wide, and features (a) short, thick rhizomes, (b) leaves that are poisonous, and (c) edible leaf stalks (long fleshy petioles). Depending on variety, leaf stalks are typically deep red to pink to green with a tart flavor. The large, heart-shaped, dark green leaves are highly toxic (oxalic acid) but ornamentally attractive. LEAVES MUST BE REMOVED AND DISCARDED BEFORE STALKS ARE USED IN COOKING. Tiny, whitish flowers form terminal panicles on erect stalks anytime between May and late summer.
Genus name comes from the Greek name for the roots and rhizomes imported from Iran (or genus name comes from the Greek word rha which is the ancient Greek name for the common rhubarb).
Specific epithet means hybrid.
'Valentine' is an early bearer and produces dark red stalks, with a tart flavor that is somewhat less acidic than other cultivars. Vigorous and few if any seed stalks. Cold and heat-tolerant.
Problems
Crown rot may occur, particularly in wet, poorly drained soils. Raised bed plantings should be considered in heavy clay soils. Also susceptible to stalk borers, beetles and rhubarb curculio. Leaf spots may occur on the foliage, but usually do not affect the quality of the crop.
Uses
Grow on the periphery of the vegetable garden where roots can remain undisturbed. Rhubarb can also be planted in a corner of the perennial border for its ornamental foliage value (large green leaves contrasting with deep red stalks), with no intent to harvest the stalks. Stalks may be used in sauces, jams and pies.