When I made the decision to “learn my weeds,” I was sure it would be pretty easy. I thought I could identify a weed by just flipping though the pages of my copy of Weeds of the Northeast and finding a picture that matched. I’ve since learned that it’s not always that easy!
I wanted to identify a weed that I’ve been seeing everywhere. You only notice this weed in the spring and fall. The leaves often have a purple tint and the flowers are a bright pink/purple. It grows in clumps that are about 6-12″ high. Weeds of the Northeast had a picture of henbit (Lamium amplexicaule) and I thought I’d found my answer. But the book also had a picture of purple deadnettle (Lamium purpureum) and it too looked like the weed I’ve been noticing. So which one was it – henbit or purple deadnettle?
Both of these weeds are similar species. While the pictures I’ve posted seem to show two very different plants, sometimes these weeds can look almost the same. The one sure way to differentiate them is by identifying how the upper leaves are attached to the stem. In purple deadnettle the leaves are petiolate – this means that there is a small stalk (petiole) that attaches the leaf to the stem. With henbit, the upper leaves are sessile – attached directly to the stem without a petiole. By looking for the absence/presence of a petiole you can tell the two apart. Since learning this, I’ve realized that the purple flowering weeds I wanted to ID are most often purple deadnettle but sometimes they’re henbit!
The good news is that the basic information about both weeds is the same. They’re winter annuals that germinate when the soil is cool and moist and they thrive in the spring and fall – that’s why I’m seeing so many of them right now. If you pick a stem of either of these weeds you’ll notice that it’s square rather than round. This identifies henbit and purple deadnettle as members of the mint family (all mint relatives have square stems). If you want to forage for your meals, I’ve read that you can eat henbit and purple deadnettle. Personally, I’m not ready for a henbit salad! And while both are common weeds, they can be easily controlled with cultivation or the use of any broadleaf herbicide.
It took me some time but now I finally know what those purple weeds are – henbit or purple deadnettle. To get more specific, I’ll need to look at the leaves.