I am considering a weeping willow-leaved pear (Pyrus salicifolia ‘Pendula’) for a dry shade area in my yard. How susceptible is this tree to fireblight in this area? Should I avoid it? Are there mature specimens growing locally, so I can see how it might look in the landscape? Does it produce fruit?
The local website of Great Plant Picks lists the ornamental pear you are asking about, and though they say it’s susceptible to fireblight, they claim it’s not much of a problem in our area. Your shady spot may not be ideal, as this tree prefers full sun. It does best with well-drained or sandy soil, and will withstand drought once established. “It can be allowed to grow with little or no pruning to become a freeform mound of wild silvery growth or it can be carefully trained yearly to accentuate its angular growth. It is not a tree for beginning pruners.”
However, Washington State University’s HortSense website mentions fireblight, which suggests it’s not unheard of here (though they say it is “not a proven problem in western Washington”). If you are certain no plant has suffered from fireblight in the spot where you were thinking of planting Pyrus salicifolia ‘Pendula,’ you could try it and hope for the best (and practice good garden hygiene–collect fallen leaves, clean pruners between pruning cuts, etc.).
Arthur Lee Jacobson’s “Trees of Seattle” (2006 edition) lists just a few. He says the tree has only been available in Seattle since the 1980s, and they are top-grafted, growing into a shape that is wider than it is tall. He mentions that it produces pears, but they are tiny, under two inches in length, and not useful for human consumption. The City of Seattle’s Ballard Tree Walk map shows one growing at NW 60th Street at 28th Avenue NW.
If a sprawling form does not suit your aesthetic, you could consider Pyrus elaeagnifolia, described by the International Dendrological Society’s Trees and Shrubs Online (based on Bean’s Trees and Shrubs): “It is very curious that this beautiful tree was not given a full description by Bean (1976b), as it was introduced to horticulture in about 1800 and has been widely planted – and is hardy – throughout our area [Britain]. Its grey- or white-hairy foliage on upright stems makes it useful in the landscape. It is a much neater tree than the ubiquitous Pyrus salicifolia ‘Pendula’ with its often uncoordinated sprawl of limbs. White Sails is a selling name attached to the thornless subsp. kotschyana.”
For a pear that has good resistance to fireblight, you might also consider Pyrus ussuriensis. The Arboretum has one listed in fair condition, received in 1986 through the U.S. National Arboretum (from seed obtained in Korea); another was listed in poor condition and no longer shows up on the interactive map [so may have been removed]. It is considered ornamental, with attractive flowers in spring (though it can take a decade to reach full flowering). It does produce edible fruit, but it is not especially known for its flavor.