Rhubarb, also known as common rhubarb or Chinese and English rhubarb, is a perennial plant that is easy to grow in the home garden. Rhubarb cultivation is practiced not only for food purposes but also for its valuable ornamental value. It is, in fact, a very beautiful and showy plant. In this article, we will introduce you to its botanical characteristics and cultivation techniques in the home garden. We will also explore its most common uses in cooking, both for fresh consumption and for processing.
But let’s start with its botanical characteristics.
Botanical Characteristics of the Rhubarb Plant
Rhubarb, scientifically known as the genus Rheum, is a plant of the botanical family Polygonaceae, present in the wild and cultivated in over 60 species. Its origin is Asian, and its use has been widespread for thousands of years. Asian populations used it for medicinal purposes, and to this day, extracts of the rhizomatous roots are used by the pharmaceutical industry. The most common species are Rheum palmatum (Chinese rhubarb), Rheum officinale (English rhubarb), and Rheum rhaponticum. Botanically, rhubarb is a perennial herb with a root system consisting of a thickened and fleshy rhizome. Large leaves originate from the large rhizome, forming a large clump that can reach a diameter of up to 2 meters. The fleshy, palmate leaves are emerald green, with an almost entire margin, and can be as wide as 80 cm. The leaves are supported by long and fleshy petioles (stalks), which take on a beautiful reddish color when fully developed. Their length can reach up to 50-60 cm. The petiole is the edible part of rhubarb and is characterized by a tangy and aromatic flavor. However, the leaves contain large amounts of oxalic acid and are not edible. Flowering occurs in April, when rhubarb produces a striking flowering stem in the shape of a panicle with numerous white flowers.
Soil and Climate Requirements
Rhubarb prefers a cool climate, which is why it is ideal for cultivation in hills or mountains. If you decide to grow it in flat areas, especially in the southern regions where the summer climate is very hot, it’s advisable to choose a shaded or partially sunny location. On the other hand, rhubarb has no problem surviving harsh winter seasons. In terms of soil, due to its well-developed root system, it requires well-worked, sufficiently fertile, and loose deep soil. For this purpose, it’s recommended to provide an initial fertilization with well-rotted manure or pelletized manure (available in specialized shops).
The initial fertilization is sufficient to nourish the plant for subsequent years. Later, it’s enough to periodically apply a bit of home compost or worm humus. Another important aspect for successful rhubarb cultivation is to avoid waterlogged soils. Therefore, it’s best to avoid excessively clayey soils. Waterlogging can cause significant damage to the root system, leading to rot and fungal diseases.
Seeding and Propagation
Starting a rhubarb cultivation can be done in several ways. The simplest, yet delicate, method is seeding, which should be done in March, in small pots or in a seedbed. Once the seedlings are large enough, they can be transplanted to the garden, usually in May. Another technique is dividing the clumps. This is done by uprooting a plant and dividing its clump into multiple parts. Each divided part is then planted, giving rise to a new plant. To ensure the success of this operation, make sure each rhizome portion has at least one bud. Clump division can be done in early autumn, between October and November. Whether starting from seed in spring or through autumnal clump division, harvesting rhubarb will begin from the second year.
Mature rhubarb plants can grow to large sizes. Therefore, it’s essential to consider proper plant spacing. Between one plant and another in a row, leave at least 1 meter of distance, and if multiple rows are planted, maintain a 2-meter gap between each row. Since rhubarb is a perennial (at least polycarpic) plant, it’s advisable to choose an area of the garden outside the main cultivated area so as not to interfere with other crops. Additionally, avoid planting too many plants, as each plant is highly productive. The planting can last for many years, but when the clumps start to decline, it’s best to renew them in a timely manner.
Rhubarb is a plant that requires minimal cultural care. Weeding is not overly demanding, as the clump’s growth and development of large leaves prevent their proliferation. However, more attention should be given to weeding in the first year of cultivation, especially if you start in spring. For this purpose, we recommend natural mulching.
Regarding irrigation, it’s necessary only during summer and prolonged dry periods. Therefore, setting up a dedicated irrigation system is not advised. Another cultural practice is cutting the flowering stem in spring. While rhubarb flowering is beautiful and ornamental, it diverts energy from the production of stalks and leaves. So, if your goal is to harvest stalks, it’s best to remove the flowering stems as soon as they appear.
Biological Pest and Disease Management
Rhubarb is very hardy, so it can resist diseases and pests. However, in spring, watch out for aphids, which can be prevented using natural macerates, such as those based on garlic or nettle. Pay special attention to waterlogging, which can lead to dangerous rot and root system diseases.
The edible parts of rhubarb are the stalks, which can be harvested gradually starting from the second year, between April and October. Harvest the stalk when it’s well developed, fleshy, and reddish. To avoid damaging the plant’s buds, twist the stalk downward with a rotating motion.
Culinary Uses of Rhubarb
Rhubarb can be used in various ways, including the creation of clean energy. However, concerning culinary uses, the roots can be used to prepare a valuable digestive bitter. Additionally, not everyone knows that root extracts of rhubarb can be used to make candies. The stalks, on the other hand, are consumed as a flavorful vegetable. They can be served raw in salads or cooked, much like asparagus. The most common use, however, is transforming them into tasty jams with a sweet and sour flavor.