Description
Hovenia dulcis
Deciduous tree in the Rhamnaceae (Buckthorn) family, also known as the Asian Raisin Tree, which is perhaps more apt as the tree is found naturally from Korea and Eastern China across to the Himalayas. This Raisin Tree is ornamental, edible and medicinal – the scientific name dulcis means sweet, and it has a long history as a food supplement and traditional medicine in Japan, China and Korea. The leaves are oval to heart-shaped and pale to bright green, and in the summer clusters of undramatic but fragrant creamy yellow flowers appear. As these decay, it is not the ovaries which turn into fruit, but the lower stalks, which swell unevenly into a fleshy, contorted mass, which is sweet, fragrant, and edible raw or cooked. They are sweetest after the first frost and can be harvested from the tree or left to fall. In China and Japan these pea-sized pseudo-fruits are often dried, looking and tasting like raisins (some say with a hint of pear), and they can be used in baking in the same way. An extract from the seed, young leaves and twigs is used as a honey substitute and for making wine and lollies.
The Japanese Raisin Tree has been used for centuries in traditional Chinese, Korean, and Japanese medicines for fever, parasitic infection, liver toxicity, stomach disorders, inflammation and as a well-known hangover cure! More recently it has been confirmed as possessing several pharmacological properties such as flavonoids in seeds and fruit, alkaloids in root, barks and seeds, and polysaccharides in the peduncles (try saying that fast!!). These exhibit a range of medicinal attributes including antidiabetic, anticancer, antioxidant, anti-inflammatory and hepatoprotective properties.
In terms of other uses the timber is fine and hard and is used for building construction and high quality furniture. This tree only casts light shade, has lower limbs which are often self-pruning, and can therefore fit very well into a forest garden/food forest system.
The Japanese Raisin Tree grows naturally on sunny sites in forest edges and clearings on moist sandy or loamy soils; on our dry clay soils it has been slow to get established but is doing fine, and in the nursery where it is irrigated we have a beautiful specimen. In the warmer parts of Aotearoa growth is more rapid and the tree is used as a key agroforestry species. In tropical countries such as Thailand the growth rates can be as fast as those of eucalyptus, up to 6m in three years, and it has been suggested as a more ecological alternative. Japanese Raisin Trees are extremely hardy in a continental climate where they have time to harden new growth, in more temperate climates they can be knocked back by winter cold snaps and suffer from some die back, and new growth in spring is very vulnerable to frost. The trees do best in a warm, sheltered position, possibly with some frost protection in the early years depending on your site, but can definitely be grown in any part of the country with appropriate care. They can grow to a height of 10m or more and are otherwise undemanding and easy to grow.
Certified organic plants, well established small grade trees, in deep root 11cm pots, approx 30 – 50 cm high
