Fruit trees and small fruits Gardening Hybridizing Pollination

When Two Different Pears Cross, Does It Change their Taste?

Small, brown, round Ussurian pear (left) and large, pear-shaped, red and yellow 'Flemish Beauty' pear (right)

If a Ussurian pear (left) is pollinated by a ‘Flemish Beauty’ European pear (right), will it take on its taste? Photo: nps.gov, emojiry.com & Mikko Heikkinen, Flickr, montage: jardinierparesseux.com

Question: Following up on the article Fruit Trees: It Usually Takes Two, can the Ussurian pear (Pyrus ussuriensis) pollinate European pear trees, like ‘Flemish Beauty’ or others? And would its fruits then become edible thanks to the presence of European pear trees nearby?

Cynthia

Answer: The answer to the first part of your question is yes: the Ussurian pear (P. ussuriensis), also called Manchurian pear or Harbin pear, happens to pollinate the popular European or common pear (P. communis), even though the two are different species. In fact, it is an excellent pollinator, producing copious numbers of flowers and it is often used specifically as a pollinator in cold climates where there is little choice of European pear trees that can be used for cross-pollination. That’s because the Ussurian pear tree, from the extreme north of Asia, is very, very cold hardy (hardiness zone 3 or even 2) compared to the European pear tree, whose different cultivars are of variable hardiness: mostly zone 5, but sometimes zone 4 or, for the very hardiest ones, zone 3.

Ussurian pears, on the other hand, are not usually considered edible. Not that they are poisonous, but the small, globular, brownish-green fruits are small, hard as a rock and quite acidic and astringent, although after a good frost which increases their sugar level, it is possible to use the fruits in cooking. Due to their small size (at only 1 ½ inches/3 to 4 cm in diameter, Ussurian pears are no bigger than a golf ball!), there isn’t much flesh to harvest, though, and the rare times they are used as human food is usually by crushing them to extract their juice.

Cross Pollination Does Not Affect the Taste

Ussurian pear tree branches covered with flowers.
The Ussurian pear tree is an excellent pollinator, but its small fruits are not really edible. Photo: Sten Porse, Wikimedia Commons

On the other hand, cross-pollination between a Ussurian pear and a European pear will in no way improve the quality of the fruit of the former. Moreover, it’s the same thing for any cross between two different plants. With very few exceptions, the fruit resulting from such a cross will be identical in appearance, texture and taste: a typical fruit of the mother plant. Just transferring pollen to a flower does not change the fruit.

So, a pear produced on a Ussurian pear tree, but resulting from a cross with a European pear such as the ‘Flemish Beauty’ you mention, will always be small, round, sour and astringent. In other words, a typical Ussurian pear. It will show no trace of any European pear influence. And the opposite will also be true: a pear produced by a ‘Flemish Beauty’ pear tree but resulting from the cross-pollination from with a Ussurian pear will have the oblong, wide-bottomed shape and the color of typical ‘Flemish Beauty’, plus the same appetizing aroma and sweet and delicious taste it is supposed to have.

Therefore, the origin of the pollen that ensures fertilization will not change the quality of either fruit, neither for better nor worse. 

If, on the other hand, if you harvest seeds from the hybrid fruit and sow them (and wait patiently: it can easily take 7–10 years for the first fruits to appear on a pear tree!), the fruits will show a mixture of traits from both parents. So, it’s in the second generation that the effect of cross-pollination is seen.

Hybrid pear ‘Ure’ with ripe yellow fruits
The hybrid pear (P. × ussuriensis) ‘Ure’ bears delicious if rather small fruits. Photo: thetreefarm.com

There are indeed quite a few hybrid pear trees resulting from crosses between the Ussurian pear and the European pear, called by convention P. × ussuriensis, of which the best known is ‘Ure’, a hardy pear tree (zone 3) with excellent disease resistance that yields an abundance of small, yellow pear-shaped fruits that are perfectly edible and delicious. In addition, it’s very ornamental, with abundant white blooms in the spring and superb fall coloring. Like most pears, ‘Ure’ is not self-fertile and will require a pollinator, preferably a Ussurian pear tree (P. ussuriensis), another hybrid pear tree (P.× ussuriensis) such as ‘Early Gold’, ‘Golden Spice’ or ‘Parker’ or even an Asian pear tree (P. pyriforme). 

The Same Rule Applies to Other Plants

It’s the same situation for other plants, by the way. If two squash or two peppers cross in your garden, it won’t change the taste or appearance of the fruit in the first year, but if you save and sow the seeds, the second generation will be a hybrid one, with mixed traits and indeed, not always the most desirable ones.

In the Animal World Too

Hybrid Rottie Poo puppy.
Crossing a Rottweiler and a poodle will result in a hybrid: a Rottie Poo like the one shown here. But that’s the second generation. The father dog and the mother dog will not change races. Photo: thehappypuppysite.com

Besides, when you think about it, it’s the same with animals. If, for example, you cross a male Rottweiler with a female poodle, the latter will not begin to develop Rottweiler traits. However, all puppies from the cross will be hybrids and will have mixed traits.

It is therefore in the upcoming generation that crossbreeding shows its effects, in both plants and animals.

Two Exceptions

There are a very few exceptions to this rule, but two of them could affect how you garden.

Corn with multicolored kernels.
Corn differs from other plants in that each kernel can, if crossed, look and taste different in the first generation. Photo: businessinsider.com
Lumpy English cucumber.
Distorted English cucumber. Photo: gardengirlcanada, steemit.com

Maize (Zea mays) differs from most other vegetables in that it undergoes a double fertilization: the pollen brought by the wind fertilizes both the embryo that will give a new plant, but also the endosperm, the grain we eat. So yes, the taste and even the color and texture of the kernel can be adversely affected by the presence of another corn variety growing nearby. Read Sweet Corn Hates Company to understand this unique situation.

The other common exception is the seedless English or greenhouse cucumber. This cucumber (Cucumis sativus) is parthenocarpic, that is, it produces fruit without being fertilized (which is why the seeds never develop). But if it is pollinated by a normal cucumber nearby, it will produce lumpy, irregular fruit with seeds. This is why it is usually grown in a greenhouse or in isolation to avoid crossbreeding. Read English Cucumbers Don’t Like Company for more information.

So, you can plant a Ussurian pear tree near your ‘Flemish Beauty’ pear tree to help it produce more numerous delicious fruit than ever, but the fruits produced by the Ussurian pear tree will remain Ussurian pears: small, hard and barely palatable. They’ll never take on the taste or appearance of a European pear.

Larry Hodgson is one of Canada’s best-known garden communicators. After studies at the University of Toronto and Laval University where he obtained his B.A. in modern languages in 1978, he succeeded in combining his language skills with his passion for gardening in a novel career as a garden writer and lecturer. He has notably been editor-in-chief of HousePlant Magazine, Fleurs, Plantes et Jardins, À Fleur de Pot and Houseplant Forum magazines and is currently the garden correspondent for Le Soleil and radio garden commentator for CKIA-FM Radio. He is a regular contributor to and horticultural consultant for Fleurs, Plantes, Jardins garden magazine and has written for many other garden publications in both the United States and Canada, including Canadian Gardening, Harrowsmith, Horticulture, Fine Gardening, Rebecca’s Garden and Organic Gardening. He also speaks frequently to horticultural groups throughout Canada and the U.S. His book credits include The Garden Lover’s Guide to Canada, Complete Guide to Houseplants, Making the Most of Shade, Perennials for Every Purpose, Annuals for Every Purpose, and Houseplants for Dummies, as well as nearly 50 other titles in English and French. He can be seen in Quebec on French-language television and was notably a regular collaborator for 7 years on the TV shows Fleurs et Jardins and Salut Bonjour Weekend. He is the President of the Garden Writers Association Foundation and the winner of the prestigious 2006 Garden Media Promoter Award offered by the Perennial Plant Association. An avid proponent of garden tourism, he has lead garden tours throughout Canada and to the gardens of over 30 countries over the last 30 years. He presently resides in Quebec City, Quebec.

3 comments on “When Two Different Pears Cross, Does It Change their Taste?

  1. SWEET!
    Thanks.

  2. Such questions come up a lot. Some people believe that pollination can change the color of flowers. For example, a while oleander can start blooming pink if pollinated by a red oleander. What is worse is the belief that two seeds planted together will somehow grow into a plant with the qualities of both, such as a red and white striped petunia that grew from the seeds of a white and a red petunia. In my own work, I sometimes encounter lemon trees that were ‘pollinated’ by a grapefruit tree, and started producing huge lemon grapefruit hybrid fruits, which are really just the fruit of the shaddock understock that suckered and dominated the lemon tree.

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