Pyrus ussuriensis Seeds | Ussurian Pear
LATIN NAME: Pyrus ussuriensis
COMMON NAME: Ussurian Pear
Plant Profile
The fruit is a small round pome, three to five centimetres across, green turning yellow with brown speckles across the skin. Bite into one that is not fully ripe and the astringency is startling, because the tannins are still mobile. The grittiness is structural: the flesh carries clusters of stone cells, lignified sclereids that crunch between the teeth.
The European pear is a soft, buttery fruit with a long neck and a fine texture. The Ussurian pear is small and hard, with gritty flesh, and it ripens early. Botanically the two graft onto one another, which is precisely why one serves the other as a rootstock. The chromosome number is 2n = 34.
Most of the cold-hardy pear trees in northern orchards are standing on Ussurian roots. Seedlings are raised in a nursery row, budded in late summer with the cultivar that is wanted, and lifted as finished trees; the rootstock contributes anchorage, tolerance of heavy soil and the ability to survive a winter that would kill a European root.
Pear cultivars graft cleanly onto Ussurian seedlings, and the union is usually strong enough to carry a full crop. The benefit is a northward shift of the line where pears can be grown at all: on this rootstock, dessert pears crop in districts where the previous generation planted only apples and plums. Where fire blight is serious, growers prefer Pyrus calleryana; where the ground is wet, Pyrus betulifolia.
The pear slug is the larva of a sawfly, black and slimy, and it strips the upper surface of the leaves in midsummer. Pear psylla produces honeydew that blackens in sooty mould and carries the phytoplasma behind pear decline. Pear scab and fabraea leaf spot are the fungal problems of a wet season, and fire blight is the one to watch every year: prune out blighted shoots well below the visible canker, disinfect the tools between cuts, and avoid heavy nitrogen feeding.
Science & Biotechnology
Breeding programmes that work on hardiness and early ripening draw on this species directly, and the Chinese white pear is thought to have arisen as a hybrid between it and the sand pear. Germplasm collections hold wild accessions from the region, and S-genotype typing is used to make sure new cultivars are compatible with their pollination partners.
Rootstock clones are multiplied in vitro from axillary buds, which gives uniform plants free of the viruses that accumulate in field-grown stool beds. Shoot-tip grafting onto seedling stocks is used to clean up infected material, and somatic embryogenesis from immature seed has been achieved across the genus.
Uses & Benefits
The tree reaches fifteen metres in good forest soil, with a broad rounded crown and grey-brown bark. The leaves are ovate, glossy and dark, turning a strong orange-red in autumn, which is why the species is planted as an ornamental well outside its fruiting range. Flowers are white and open early, usually with or just before the leaves.
The tannins and acidity make this a processing pear. Pressed after softening, it gives a juice with real body and a clean, slightly bitter finish; sweetened, it makes a good nectar and a useful blending base for cider-like drinks. In north-east China the juice is sold as a winter drink and the fruit is used in cough remedies.
Let the fruit soften for a week or two in a cool shed, then crush and press it. The must is low in acid compared with an apple, so it benefits from a little lemon juice or from blending with a sharper fruit. Because the flesh is gritty, yield is modest unless the pulp is well broken down, and a coarse chopping before pressing helps.
In the Russian Far East and north-east China the tree is planted as a windbreak and a street tree, on poor ground where it tolerates cold and drought. The early flowers are one of the first substantial pollen sources for bees in a cold spring, and the autumn colour is a reason to plant it. Where the fruit is not wanted, plant a single tree and let it flower without a polliniser.
Growing from Seed
Sow the seed in autumn in an outdoor bed or a cold frame, one to one and a half centimetres deep, and let the winter break the dormancy. Seedlings raised for rootstock are lined out 25 to 30 cm apart with 60 to 90 cm between rows and budded at about 20 cm above soil level in late summer.
The seedling makes a strong taproot, so lift it with a fork pushed deep rather than pulling, and trim the taproot when lining out to encourage a fibrous system. Orchard trees are spaced five to seven metres apart and trained to a central leader or an open centre; because the species is self-sterile, plant a second pear that flowers at the same time. Water deeply and infrequently, mulch the root zone, and keep nitrogen low.
Our Take
For a cold garden this is the pear that makes the crop possible, whether the fruit is eaten or the tree is used purely as a rootstock for something better. Choose your rootstock to suit the ground and the disease pressure: the birchleaf pear handles wet soils that would rot a Ussurian root, the Callery pear is the fire-blight-resistant option for warmer districts, and the Siberian crabapple, Malus baccata, is the cold-hardy root for apples.
Related Reading
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