Is this one of the so-called trees? If so, let's try and get a real identification!

A strange, upsetting aroma wafts from certain trees in Davis during the spring and summer. Basically, the trees smell like ejaculate — hence, the term Cumbleberry.

In fact, there are many different kinds of trees and shrubs with a vile-yet-familiar stench:

But in Davis, the main culprit is the Evergreen Pear (Pyrus kawakamii). According to a source at the UC Davis Botanical Conservatory, the city planted this tree because of some attractive properties unrelated to the offensive reek: it grows to a well-proportioned height of 15 to 30 feet and no taller; its roots won't lift the sidewalk; it retains most of its leaves throughout the year (harsh winters make it go somewhat deciduous); if leaves don't fall off during the winter, nobody has to sweep them out of the street; and its small, white flowers look nice from a distance. The leaves are medium-sized, bright green and glossy, and the bark is dark brown and coarse. Rootsuckers are a bit of a problem, and require some maintenance now and then. So don't hate. P. kawakami can bloom as early as January. Pyrus calleryana varieties are more commonly noticed in bloom, as they flower in February and March and are more common. The odor of their flowers resembles wet socks. Bradford is the best-known variety, planted along F Street between Fifth and 14th Streets. At that end, the similar trees are P. kawakami. Bradford has a problem with poor branch angles, causing the trees to split apart after 15 - 20 years. They are no longer included on city street tree lists. P. calleryana 'Aristocrat' is planted in many places in Davis, particularly along Covell Blvd. between Anderson and Sycamore. Stinky flowers are among the many problems of Aristocrat pears: mistletoe and a propensity for fireblight disease make it a not-recommended variety now.

Locations

For more on local plants see Town Flora.

Aren't those trees called "society garlic?" —jr

No. Society Garlic is Tulbaghia violacea, of the Alliaceae family. They're pretty bushes, with long thin green leaves and violet flowers. Oniony scent. Apparently, they used to be considered edible, but nutritionists are now thinking otherwise. Photo (not my site) here: http://davesgarden.com/pf/showimage/25920/ —JudithTruman

Just for the record, Davis Wiki is the only place I have ever seen or heard the term "cumbleberry". It is not a common name, and a Google search produces only this page and other Davis Wiki pages. Pyrus calleryana smells worse, and rather more intensely so, than Pyrus kawakami. —DonShor

It's also likely the only place you'll find the Sidewalk Crack Project. Silliness abounds in Davis ("This Hole Sponsored by River City Bank"), and that's pretty true of the wiki that represents it. They both have their serious moments too. —jw

http://www.youtube.com/watch?v=aHze0SqB5Zg This is a relevant video. —VinceBuffalo

A Calleryana pear, probably Bradford variety, in bloom: