How do I manage the invasive bamboo species on my property?

Question:

I have some soft of invasive bamboo species that was introduced to my land by a utility tree truck a few years back. I am tackling it now and ripping up the root balls but I can’t find what species it is on your website. I was able to find a few photos of them fully grown last year. Any help would be appreciated. At the end of summer they definitely bloom large flower/seed pods that start white and turn purple.

Answer:

Jonathan Foster, Home Horticulture Outreach Professional

When I read the description, I worried you might be dealing with Japanese knotweed (Fallopia japonica), but am now leaning toward American pokeweed (Phytolacca americana) after seeing the photos and comparing them to your description. The two species are often confused with one another, but the pokeweed has longer, narrower leaves and distinctive, pendulous red-purple fruits at the end of the season, while knotweed has heart- or shovel-shaped leaves and its fruit is a small, white, winged samara (like a maple) with dark seeds. The hollow stem is a little worrisome, as that is more commonly seen in mature knotweed, but pokeweed has partially hollow stems, so it’s not a dealbreaker. It is unusual to see such a dense thicket of pokeweed, as well as the (as far as I can tell) uniform green of the stems, as they are more commonly green-into-red as the season progresses.

I consulted with a few colleagues, and we all agree this is most likely pokeweed, but with a slightly uncommon appearance/habit. So, first let me direct you to a resource where you can do a little home recon on which you’re dealing with, just to make sure. Next, to cover the bases, I’m going to offer some sites to help with controlling each of these plants (just in case you discover you’re dealing with knotweed):

Oregon State Univ Extension page on controlling Pokeweed (includes further help on positive identification, also discusses manual and chemical control)–NB: pokeweed is a highly toxic plant, both to ingest and to touch, so please keep pets and children away and use protective clothing and gear when dealing with it.

State of Maine Page on Japanese knotweed (includes description and control suggestions)–NB: Japanese knotweed is an extremely aggressive and persistent weed, and will take diligence and perseverance to eradicate. Let’s hope this isn’t your plant because it’s a big, dense patch in your yard.

Good luck, be careful, and happy gardening.