Ask Dr. Phipps: A Weedy ID

By Phipps Master Gardeners

Q: I have a number of volunteers of this plant (see photos) in my yard in Squirrel Hill and I haven’t been able to identify it.  My neighbor had planted a few of them (they don’t know what they are either) and it appears that their plants are spreading aggressively.  Their plants get to be 4 to 5 feet tall.  Can you tell what it is and if I am going to be sorry if I don’t pull it out before it takes over?!  

A: This is one plant with which I am unfamiliar. After doing some searching, it seems to be a plant called seedbox, Ludwigia alternifolia, in the Evening Primrose family. It prefers wet conditions, so depending on your site, it may not be a problem. It spreads by seeds, hence its name! Other than in some wetland sites, I did not find information that said it was an overly aggressive weed. But based on what you describe of the plant spreading through your neighbor’s yard and already in to your yard, I would pull it out. Over time, you will be able to see how it looks in your neighbor’s yard and if it turns out that you like the look of it you can keep future volunteers that appear in your yard. Depending on what plants you are currently growing and how well manicured you keep your current gardens, you may want to pull it now. If you like a wilder look, you can keep it. See this link for identification and a little more information.

A Note on Plant ID: I really like this website for identifying unknown plants, especially if I am home and can use my computer.  I like that you can select various characteristics in order to hone in on the identity of a mystery plant.  After I find a plant that I think is the same as mine, I google the name to learn more about it and to be sure that it shares all of the similar characteristics of the unknown plant. 

If I am out and about and I have my phone with me, I like to use the Seek app, by iNaturalist.  It is fun, because it allows you to identify plants and animals, it keeps track of your findings, and gives you useful information about your mystery plant or animal.  I have even used it to identify interesting flowers and insects when I travel.  Here is some more information about the app. 

Photos © Fritz Flohr Reynolds