Pyrus betulifolia Seeds | Birchleaf Pear

Birchleaf Pear (Pyrus betulifolia) seed — Birchleaf Pear (*Pyrus betulifolia*): Rosaceae, tribe Maleae — Pyrus, native to Dry hillsides and river terraces in northern and central China, from Gansu and Shaanxi through Shanxi, Hebei, Henan and Shandong to Liaoning, and in Korea.

LATIN NAME: Pyrus betulifolia

COMMON NAME: Birchleaf Pear, Tang Li

Plant Profile

For generations the nurseries of the north have raised this pear from seed and grafted the named varieties onto it. The stock brings cold hardiness, tolerance of drought and a capacity to grow on the calcareous soils of the loess country, where many fruit trees yellow and stall. It grafts cleanly with the Asian pears and is used in the same way in Japan for the round-fruited nashi. The warmer south relies more on the other Chinese wild pear that names this genus so often in orchard literature.

The second Chinese stock species is the Callery pear, the parent of the ornamental cultivars that spread so aggressively through North America. The two are easy to confuse in winter and easy to tell apart in growth: the Callery pear’s young shoots are smooth and its leaves glossier, while the birchleaf pear’s shoots are woolly and its foliage greyer and narrower. The important difference for a gardener is behaviour. The birchleaf pear is the thornier and hardier tree, and it has not developed the same invasive habit, which makes it the safer choice where a wild pear is wanted.

Fire blight is a bacterial disease caused by Erwinia amylovora that blackens flowers and shoots as though they had been scorched and can kill whole limbs, and pears are among its favourite hosts. No rootstock is immune, but a hardy, drought-tolerant stock lets a grower replace a top without losing the orchard, and this species has been used in breeding for hardiness in cold, dry districts. Prune out infected wood well below the visible canker and clean the tools between cuts, because the bacterium travels on blades.

Science & Biotechnology

Pears carry gametophytic self-incompatibility, a system in which the pistil rejects pollen carrying the same recognition gene as itself. The female side of that rejection is an enzyme of the S-RNase type, which degrades the RNA of incompatible pollen tubes before they reach the egg. In an orchard the practical consequence is that a block of one variety cannot fertilise itself, and a polliniser with a different set of these genes must be interplanted, with flowering times that overlap, which is why a lone pear tree in a garden often flowers well and fruits badly.

Pears accumulate arbutin in the fruit and the leaves, a hydroquinone glycoside that has been studied for a long time as a skin-depigmenting agent and is extracted commercially from pear material and from bearberry. Chlorogenic acid and caffeic acid are the other abundant phenolics, and they are part of the reason a cut pear browns. The birchleaf pear’s own fruit is too sour to eat, so that chemistry matters mainly through the grafted varieties it feeds.

Uses & Benefits

The flesh of any pear holds sclereids, the stone cells that give the fruit its characteristic grit, and in this species they are densely packed in a small, hard, brown fruit about the size of a cherry. Nobody eats it raw. It is cooked or fermented instead, and the tree’s value to wildlife is the crop of small fruit that birds strip in autumn and carry away, dropping the seed along hedges and field margins.

Growing from Seed

The leaves are small and narrow, ovate to diamond shaped, grey-green and glossy above, on long slender stalks, and the young shoots and leaf undersides are woolly, a detail that separates the species from its smooth-shooted relative at any season. The branchlets harden into thorns on the short spur shoots, so the tree is armed at every age.

Collect the fruit when it softens, wash the seed free of pulp, and store it in a bag of moist sand in a cool place so that the seed can finish ripening through a cold, damp period. Sow into a deep, freely draining mix, because the seedling makes a long taproot and resents a shallow pan. Grow the stock on for one or two seasons until the stem is pencil thick, then graft at about four centimetres above soil level with a whip-and-tongue cut. Set the stocks thirty centimetres apart in the nursery row so that the roots have room, and give the young tree full sun and deep, well-drained soil once it is planted out. Keep the crown open by removing the water shoots and the crossing branches in winter, and prune lightly, because a heavy feed or a hard cut produces soft growth that fire blight prefers.

Our Take

I grow this species for the moment when every branch shows its thorns against the white blossom. If you want the ornamental side of the same genus, the Callery pear is the famous and invasive one, while the Ussurian pear is the other cold-hardy Asian species that fruit breeders return to. For early blossom on dry ground, the Siberian crab apple is a useful partner in the same row.

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