Growing Asian Pears


Asian pears are a sweet, edible fruit produced by an Asian pear tree (Pyrus pyrifolia). Asian pears are grown primarily in China, Korea, and Japan, where they have traditionally been planted and bred for over 3000 years. In the 1820's Asian pears were introduced Flushing, NY and made their way with immigrants and settlers in the 1850s to California - where they have become a valuable and popular crop. Today California and Oregon are the largest producers of Asian pears in the United States! Asian pears can be divided into two types: the mild, sweet, smooth-skinned kind and the more intensely flavored, russeted types. There are hundreds of varieties of Asian pears, so it's important that you choose the right ones for your area!




Choosing a Variety


Size


Grafted Asian pears are all similar sizes that can be maintained at approximately  15' to 20' tall.




Pollination


With few exceptions, Asian pears are not self-fertile trees and will need another variety of Asian pear tree nearby for cross pollination. Despite being related, Asian and European pears are not reliable pollinizers for each other due to a lack of an overlapping blooming period; Asian pears bloom a week or more before their European cousins.


The pollinizers should be planted no further than pollen-carrying bees will fly, with no line of sight obstruction, to ensure proper cross-pollination. That distance varies with different bees; 100’ is a good average distance.




Ripening Time


Asian pear tree fruit generally ripens from mid-summer through early fall, depending on the variety and your location. As you make your selections, remember that early-flowering trees do not necessarily mean early-ripening fruit. Generally speaking, your Asian pears are ready to pick when they begin falling from the tree. Some varieties come off the tree easily when ripe, simply by lifting the fruit above the stem attachment; others take a bit more effort. While some cultivars arguably store longer than others, as a rule all types of Asian pears store exceptionally well in your refrigerator at home!





USDA Plant Hardiness Zone


Asian pear trees are hardy to USDA zones 5-9, unless otherwise noted. This rating tells you the minimum winter temperature the plants typically survive when properly hardened off. Make sure you consult the USDA Hardiness Maps website, which provides information on the average minimum winter temperature in your location, by zip code. Your USDA Plant Hardiness Zone does not reflect the many other factors in successfully growing Asian pear trees, including length of growing season, rainfall amounts, soil quality, and chill hours. Consult your local extension service for more detailed information about your local growing region and the factors you will need to know when selecting fruit trees for your home orchard.





Chill Hours


All plants have what are called a "chilling hour requirement" in order to flower and produce fruit. Chilling hours are defined as the cumulative period of time between 45 and 32 degrees Fahrenheit and vary from region to region. The majority of fruiting trees have a chilling hour requirement of anywhere from 500-1000 hours, with some requiring more and a few requiring as little as 200-300 chill hours to blossom and produce. Fruit trees that require less than 600 chilling hours are considered "low chill" and are generally more resistant to more intense summer conditions than fruit trees with higher chilling hour requirements. The general chilling hours available for you specific location can be found online or determined by your local extension office.





Where to Plant your Plant


Asian pears need to be planted where they receive at least 8 hours of direct sunlight measured in early summer (late June to early August). Sufficient sun exposure triggers the initiation of new flower buds for the next growing season, without which there will be no fruit. Fruit ripening and flavor development are also benefited by the carbohydrate production stimulated by the sun, as well as its heat.

Asian pears tolerate a wide variety of soils so long as they are well drained and moderately rich, with a pH around 6.3-6.8. Improve your soil where you intend to plant by mixing an inch or two of plant based organic matter (manures are best for vegetable/fruit soils), peat, or coconut coir into an area 1 1/2 to 2 times the diameter of the needed planting hole and up to a foot deep. A 2-4” deep layer of mulch (straw, leaves, or wood chips) applied after planting will continue to improve the soil, reduce weed competition, and increase moisture retention.

Allow sufficient space for both the top of the tree and its roots when selecting the planting location. Refer to size descriptions for each variety, keeping in mind these are generally managed or pruned sizes, not maximum potential sizes. If you are planting an orchard be sure to include enough space between rows for transporting supplies in and fruit out.





Growing in Containers


Asian pear trees generally grow too large to successfully grow in a container for more than a few years.

Do not exclusively use soil from your garden in your pot; instead, use up to 1/3 native soil, 2/3 potting soil mix, and add a generous portion of fertilizer-free compost or well-rotted manure. For larger pots use a potting mix that has a larger particles in addition to smaller ones.





Care and Maintenance


Fruit Thinning


Asian pears are unusually fruitful plants. They mature early (usually starting blooming and producing fruit 1-2 years after planting), and they set LOTS of fruits! In fact, unless you aggressively thin the fruits, you will have hundreds of small pears that are mostly skin and seed. 


After the traditional self-thinning event known as "June drop" - which usually occurs in early June and consists of the tree spontaneously releasing up to 10% of its fruit - you should go in and thin out 40%-50% of the remaining fruits. This seems excessive, but the remaining fruits will swell and develop into the good-sized pears you want them to be. In clusters of 1-3 fruits, thin to the best single fruit; in clusters of 4+ fruits, thin to the best 2. 


DO NOT SKIP THIS TASK. If allowed to expend all of its energy ripening the fruit it has set, the young tree will exhaust itself and "runt out" - stay small, thin, poorly rooted, and die early. Asian pears need to be thinned to moderate the vigor we have bred into them. Thorough thinning will make better fruit and promote a healthy, well-rooted, long-lived addition to your home orchard.



Watering Your Plants


This is the most important and often the most difficult part of successfully growing plants. There are many factors, including the humidity, temperature, soil type, wind, and amount of direct sun that affect how much and how often water should be applied.

A general rule of thumb for plants in the ground is to ensure they receive an inch of water per week over the root zone. An inch of water is equivalent to about ¾ to one gallon per square foot of soil surface area. The typical three foot diameter planting hole would need 7 ½ to 10 gallons of water per week provided by rainfall or by the gardener.

Apply this water once a week, two times per week if soil is fast draining. This will of course depend on your own conditions and the plants you are growing! DO NOT water lightly each day because this results in a wet surface and dry root zone area. The soil should be moist, but not soggy, to a depth of about a foot for most growing plants. The top inch or two can feel dry, and the plant will still be well watered. The trick is to have the water available where the roots are. In hotter and sunnier areas, a mulch of wood chips, straw, bark, etc. can greatly ease the burden of summer watering. For plants in containers, water until the soil is saturated and water comes out of the drainage holes. Let the container dry until the soil is dry to the touch 1 to 2 inches down (more deep with deeper pots) and the container is lighter in weight. A plant that has wilted can be receiving either too much or too little water.

In rainy areas like the Pacific Northwest most of the plants that we offer will need relatively little supplemental irrigation ONCE THEY ARE WELL ESTABLISHED in the ground and have had a chance to develop a good root system. However, even here it is important to make sure plants have regular, deep watering during the first couple of growing seasons, and the first summer is especially critical. In drier areas, or where soils do not retain water well, permanent irrigation is essential. Remember that you don’t want your trees to just survive, but rather to thrive. Make sure they get the water where they need it, starting at the drip line and extending away from the tree up to several feet ( for older trees) where the feeder roots will be. Drip irrigation and soaker hoses can be an efficient way to deliver the water.


Fertilization


For good steady growth and high productivity, your trees need to have adequate amounts of various mineral nutrients. Some people are fortunate and have naturally rich, fertile soil.

Use an all-purpose or balanced fertilizer. A couple of inches of well-rotted compost on the root zone can also be an effective fertilizer. A generous leaf or straw mulch around your trees will not only conserve moisture and help in weed control, but also keeps your soil healthy by building up humus, attracting earthworms, and supporting beneficial fungal organisms. This encourages young trees to be strong, healthy and productive. Avoid applying fertilizer after early summer; doing so can encourage lots of soft new growth that is much more likely to be damaged by winter cold. Excessive use of fertilizer can increase disease problems on your plants and can even kill them.

As a general guide, if your tree is producing about one foot of new growth or more a year and has healthy-looking foliage, it may not need much, or any, fertilizer.




Pest and Diseases


Find out what insects and diseases are typical in your area. Ask your local co-operative extension professional what the typical insect and disease issues are in your area. Then you can make selections based on resistance or tolerance information available on our website, or make a plan for controlling problems you can expect with the susceptible varieties you prefer to grow. If you see resistance information about a particular disease for one variety but not another of the same kind of fruit, then that variety may be susceptible or might not have been tested - so its resistance could be unknown. The following are some of the more common issues.

Pear Slug


Symptoms

Dark olive green slug-like larvae that skeletonize leaves. Especially common in summer months.

Control Methods

Insecticidal soaps (e.g. Spinosad). Pyrethrin, rotenone dust, or bioneem. Pick off and destroy by hand.

Comments

Trees can tolerate up to 25% defoliation with little harm. May also infest plum, cherry, hawthorn, or mountain ash trees.


Pear Psylla


Symptoms

Lots of tiny yellow/red insects which secrete honeydew, causing sooty mold.

Control Methods

Insecticidal soaps or rotenone dust, spray in spring. Dormant and delayed oil and lime sulfur. Superior oil sprayed 2-3 times through the summer.

Comments

Insects prefer soft, vigorous growth. Prune out suckers and manage fertilizer and pruning to minimize unnecessary vigor.


Blister Mite


Symptoms

Small, oval, pointed, and raised blisters on leaves. Russeted sunken spots on fruit.

Control Methods

Pick off and discard affected leaves when discovered, but take care not to defoliate tree. Oil spray with lime sulfur in October and November as well as in the spring when buds swell.

Comments

Orchards under good integrated pest management usually are not infested with blister mites. Blister mites often attack trees in abandoned or neglected orchards.


Pseudomonas


Symptoms

Black cankers on stems, wilting blackened leaves. Resembles fireblight.

Control Methods

Plant resistant varieties. Fixed copper spray in fall or early spring. Delay pruning until warm weather in late spring all frosts.

Comments

Pseudomonas is most severe when spring frosts damage bark or when pruning is done in winter or early spring before bud break. Newly planted trees are especially susceptible.

 


Fire Blight


Symptoms

Shoots wither resembling shepherd’s crook. Leaves die and turn black or brown, but remain on tree.

Control Methods

Prune out all infected shoots, cutting at least 12 inches below infection. Disinfect tools between cuts. Fixed copper spray in fall and early spring, or use Bordeaux mix.

Comments

Especially common on pears in warm wet springs, but may also affect apples in bad years. Plant resistant varieties. Prune to promote good air flow.


Deer


Symptoms

Browsed shortened branches. Leaves are obviously munched on or plants are pulled up.

Control Methods

Fences or cages at least 8’ tall. Plastic mesh, electric, or woven wire fences.

Comments

At Raintree, an 8’ woven wire deer fence has worked best. Repellents don’t work consistently and, aside from fencing, only trained large dogs patrolling the perimeter are effective.


Bird


Symptoms

Fruits disappear or have gaping holes in them. Strawberries, blueberries, cherries and filberts are most susceptible but most fruits suffer occasionally.

Control Methods

Reflective Bird Scare Tape can work well. Bird netting. Cages.

Comments

Blue Jays start harvesting filberts when ready to pick, and so should you. Nuts dropped by jays are usually empty.


Vole/Mouse/Rabbit


Symptoms

Bark eaten in a band from soil level up to 8” and roots eaten too, usually in snowy areas with lots of mulch or tall grass at base of trees.

Control Methods

Keep mulch 4”-6” away from trunk. Keep grass short and 1’-2’ from trunk. Use vinyl tree guard wrapped around trunk until tree well-established.

Comments

Voles and mice will chew a couple inches above ground and also into the root system. Rabbits will chew up to 8” high, particularly apple trees.


Aphid


Symptoms

1/32 to 1/8” long pear shaped insects that multiply rapidly, especially on the underside of leaves and on stems. Can be pink, green, black or white. Leaves show red blisters or are curled-down and stems turn black with sooty mold.

Control Methods

Natural predators like lady bugs and parasitic wasps often provide control. Knock aphids off with water spray. Spray with Pyrethrin, Rotenone, Insecticidal Soap, or delayed dormant oil. Control ants if they are also present.

Comments

Trees can tolerate some infestation. Monitor in late spring and summer. Control is more important on new trees. Grow plants that attract predators, i.e. dill or yarrow.


Ants


Symptoms

Numerous ants scurrying up and down the tree trunk; aphids, scale or mealybug present in large numbers, lots of sticky honeydew, perhaps sooty mold.

Control Methods

Find hill and apply pesticide. Apply Tangle Trap over 2-3” wide band of paper wrapped around trunk. Eliminate other pathways into tree.

Comments

Ants nurture and protect these insects in exchange for their sugary secretions. Insects may be difficult to control until the ants are controlled.


Brown Marmorated Stink Bug


Symptoms

Poking-type feeding damage followed by decay on fruits, nuts, berries and leaves. Deformity in the healthy tissue surrounding the dead tissue. Brown spots can show up in stored fruit.

Control Methods

Monitor with traps, some broad spectrum pesticides may work. Researchers are working on finding effective controls, but no info has been released yet.

Comments

BMSB over winters in groups in dry protected areas, such as houses. If you find them on or in your home use the vacuum, squishing releases their defensive stink.  See stopbmsb.org for more info. Feeding begins in spring when the weather warms up and continues until new adults go dormant for winter.


Rust


Symptoms

Lesions on the upper surface of the leaf, or on the fruit or stems, followed by orange-ish structures on the bottom side of the leaf, or on the fruit or stems, which produce spores.

Control Methods

Copper fungicide after harvest before fall rains and again in early spring for prevention of some\ rusts. Remove and destroy infected parts of the plant. If possible select resistant varieties. Many varieties have not been studied. Cedar-apple rust is a problem east of the Rockies.

Comments

Rust diseases require an alternate host, removing the host (within 900’ radius), applying fungicides, or removing infected parts may help. Check with your extension office to see what rust diseases in fruiting plants may be common in your area, and their alternate host.


Sunscald


Symptoms

Vertical splits in bark appear spring or early summer, usually on the south or east side of the tree. Disease or insect infestations may then occur.

Control Methods

Whitewash trunk and lower limbs with interior latex paint cut 50/50 with water each fall until bark has thickened. Avoid planting in frost pockets or where water collects in winter.

Comments

Injury occurs during pattern of warm days followed by freezing nights. Sap gets stuck in trunk, freezes, then rapidly thaws in the warm sun the next day, rupturing cells.