The Sorbus aucuparia is a tree belonging to the Rosaceae family. It is also known as the red rowan or wild rowan and is a close relative of the Sorbus domestica, a classic fruit-bearing tree. The common names for Sorbus aucuparia are rowan, mountain ash, witch wiggin tree, keirn, and cuirn. These names originate from the historical use of this tree in the countryside. Birds are particularly fond of its fruits, to the point of being attracted in flocks. Bird catchers, hence the name “bird-catcher”, used this tree as bait to capture the birds using nets.
The fruits of this tree are edible and rich in beneficial properties, but they also have some toxic qualities. Therefore, they should be used with caution. In this article, we will discover the botanical characteristics of the rowan tree, garden cultivation techniques, and, most importantly, the correct way to use its fruits.
Description of the Rowan Tree
The Sorbus aucuparia is a small to medium-sized tree, typically reaching heights of 10-15 meters, although it can grow up to 20 meters in fertile soil. It is not very long-lived, with a lifespan of about 80-100 years. It is characterized by a slender trunk, up to 50 cm in diameter, which is straight and densely branched in the upper part. It can also grow in a shrub-like form with multiple trunks. The crown has an oval shape in young trees, becoming rounder in older specimens. The branches are horizontal, with a more or less ascending posture. The younger twigs are covered with fine hairs. The bark is grayish with a smooth surface and linear lenticels. The buds are rather large, ovoid-conical in shape, tomentose, but not sticky like those of the domesticated rowan. The roots consist of a deep and robust central taproot with numerous secondary lateral roots that anchor the tree to the ground.
The leaves of the rowan tree are arranged alternately on the branches, with very short petioles, and are pinnate, consisting of 7 to 13 small leaflets. These leaflets are oblong, often rounded at the base where they are asymmetrical, with an acute apex. The margin is entire at the base and serrated in the rest of the leaf. The upper side is dark green and glabrous, while the lower side is lighter and only occasionally slightly hairy along the midrib, which turns red in autumn. Sorbus aucuparia is a deciduous species, shedding its leaves in late autumn.
The flowers of the rowan tree are numerous, with up to 100 in a single inflorescence, arranged in terminal corymbs on the branches. The inflorescence is slightly hairy or almost glabrous, with five pubescent triangular sepals that curl inward after flowering. The corolla consists of five oval or round white petals.
The flowers have a strong odor, similar to that of chestnuts. Blooming occurs from May to July, depending on the altitude and seasonal climate trends. The flowers are visited for pollen and nectar by bees (although monofloral honey production is challenging in apiculture) and other pollinating insects.
The fruit of the rowan tree consists of a few achenes enclosed in a false fleshy fruit, originating from the receptacle that enlarges during maturation. The false fruit is a globular pome of scarlet red color, gathered in large clusters, dense with fruits and heavy. It has a typically tart taste.
Toxicity of the Seeds
The achenes of the rowan tree, i.e., the seeds, are toxic to humans as they contain amygdalin, a cyanide derivative. For this reason, all uses of rowan tree that we will see shortly should not involve the presence of seeds. Of course, this toxicity is irrelevant to birds, which contribute to the tree’s spread through seed digestion.
How to Cultivate the Rowan Tree
The rowan tree is highly adaptable. In the wild, it grows spontaneously in isolated specimens, occupying rocky areas, steep terrain, forest edges, and clearings in deciduous and coniferous woods. It is frost-resistant and thrives at altitudes between 400 and 2400 meters above sea level. It is a moderately heliophilous species and can be cultivated in partial shade. It thrives on various types of soil, although it prefers loamy, moist soil rich in organic matter.
Cultivation for Ornamental Purposes
Cultivating the rowan tree in gardens is recommended primarily for ornamental purposes or to create ecosystems that encourage the presence of beneficial insects and birds. To start cultivation, you can use seeds, but germination and initial growth are slow. It is much easier to buy nursery plants that are a few years old. However, finding nurseries with availability can be challenging since it is a wild and marginal fruit.
Another solution is the semi-woody cutting, taken and planted in late summer. The best time to plant it in open ground is in the autumn. In the planting hole, you should add well-rotted manure or other organic fertilizers. Irrigation is only necessary during the first year after planting. The tree is highly resistant to late-winter pruning, which is necessary to maintain an orderly and adequately illuminated crown.
Harvesting Fruits and Seed Removal
The fruits of the rowan tree should be harvested when they reach full maturity, which occurs in late autumn, preferably after the first frosts. They persist on the tree and can be found throughout the winter. However, as mentioned earlier, the seeds inside are toxic and should be removed from the rest of the pulp by manually deseeding the fruit. This is why the modern distribution of red rowan is rather limited today.
Storage and Culinary Use
The fruits of the rowan tree have a pleasantly tart taste. Once cleaned of seeds, they can be used fresh to make jams, jellies, or liqueurs. They can also be dried and stored in glass containers for other purposes.
Properties and Use of Dried Fruits
The dried fruits of Sorbus aucuparia contain pectin and tannic substances, organic acids (especially sorbic acid), and sorbitol (or sorbitol). Sorbitol is a polyalcohol, an excellent sugar substitute for diabetics, and has long been used in the preparation of pharmaceutical syrups and dietary products.
The dried fruits of Sorbus aucuparia have astringent intestinal properties, useful for enteritis and diarrhea. They also have diuretic and anti-inflammatory properties for hemorrhoids. For external use, they can be used in cases of throat and tonsil irritation. The simplest homemade preparation of dried fruits, devoid of seeds, is the decoction, with a dosage of 3 g per 100 ml of water.
Uses of Rowan Wood
In ancient times, the wood of the wild rowan tree had various uses. It is indeed a valuable wood, hard in texture yet compact and elastic. It was commonly used in cabinetmaking and carving for the construction of musical instruments such as flutes.
The Symbolism of the Rowan Tree
The rowan tree held strong symbolic significance for the ancient peoples of Northern Europe. For the Druids, it was a magical tree that was sacrificed with fire to invoke spirits. The Celts believed that the fruits were the food of the gods, which is why the tree was sacred. Furthermore, for the same reason, it was planted in front of homes to ward off evil spirits and misfortunes.