The Weedalogue is a project to identify the weeds known in Philadelphia Pennsylvania.

Ralph Waldo Emerson once said: "What is a weed? A plant whose virtues have not yet been discovered."

My experience and research suggests that Emerson was wrong. I would say that it is closer to the truth to say that a weed is a plant whose virtues have been forgotten. Quite a few of the herbaceous plants included in this compendium were used either as a food source or medical product in times gone by, and in many cases, still today. I have not endevoured to explore or elaborate on the uses of each plant. Once a plant is positively identified (and that means more than taking my unprofessional word for it), the user can research the virtues of the plant elsewhere online.

So we are left to define the term "weed." There are many definitions of the term "weed". Some people try to constrict the term to invasive species, for instance, but that is far from the only definition. Agriculturally speaking, a weed is a plant that causes economic loss by competing with crops. This definition holds little ground, however, in a city with little agriculture.

The more botanical definition of a weed is a liminal species, meaning one that grows in border spaces or times. Border spaces include timberlines, riversides, roadsides and other such spaces. Border times include wildfire clearings, construction sites and other man-cleared spaces. These liminal plants grow quickly, filling up space and are generally over-run by other species as a more stable ecology is able to establish itself. Weed trees, for instance, are the soft-wood trees that grow fast in clearings, but are eventually over-run by hardwoods able to stand the test of time.

The simplest definition is that of a gardener and landscaper. A weed is a plant that self-propigated where it was not meant to be. An oak tree that sprouts in a lawn is a weed, despite the fact that oak trees are generally not considered weeds. For the purposes of this work, a weed is any plant which decided of its own nature to grow somewhere it wasn't intended to (by human standards). This means that the term here covers, in practical usage, any self-established plant. Any plant that grows in a pavement crack uninvited is automatically a weed to me and this alone will warrant inclusion in this work.

In reality it would be better to call this a collection of wild, naturalized and escaped garden plants but the name goes back to the very beginning of this project, when it was just a note-page identifying the weeds that were found growing in the Broad and South Community Garden, which is no more. I regularly get people trying to argue with me over what is a weed and what isn't. People even seem offended when I refer to an ornamental species that they like as a "weed", even when it is growing out of the middle of the road. We do not use the term as a judgement. If you have a problem with my use of the term, get over it or at least keep it to yourself please. I will no longer respond to argumentative e-mails about the true nature of "weeds."

A word should be spoken here on the term "wildflower". Like "weed", this term has little true meaning. Gardeners often use it to describe certain species that are weedy and tend to self-seed. A more solid definition would be a wild flower, meaning one not cultivated. If it is a flower that grows wild, it is a wildflower. Even cultivated agricultural and ornamental hybrids can naturalize and become pest species. Generally, a weed appreciated for its pleasing flowers is considered a "wildflower."

In selecting plants to include here, I made a few conditions. I had to find at least one specimen of the species where it was almost certainly self-established. One cannot ever be entirely certain, so I settled for a 90% certainty. Anything found growing out of a pavement crack or building foundation was given automatic inclusion. The second condition was that it must have been found within the limits of Philadelphia. This includes such areas as Chestnut Hill, Germantown and West Philly but not the surrounding suburbs. All of the photographs included here were taken within the limits of Philadelphia.

In supplying photographic imagery of the plants, I have in many cases given examples of the plants under cultivated circumstances. This allows a more well-rounded view of the plant. This is especially important in the case of naturalized or naturalizing plants. In the case of trees, such as the London planetree, I thought it best to show the full-grown planted specimens in the local parks that actually generate the hundreds of seedlings, rather than just show the seedlings.

Most of the research for this project was done online, with some help from fellow gardeners and some book research. The accuracy of any statement or plant identification is not guaranteed. Corrections have already been made and I am certain that many will be made in the future.

It has become painfully apparent that scientific taxonomy of plants is far from perfect and many sources disagree on many species. I started the project by following what seemed to be a general consensus, but have revised the project to now generally follow the system set out by the U.S.D.A. on their "PLANTS National Database".