Dodder, a member of the Morning Glory family, is an annual here in Ohio, but it readily self-seeds unless steps are taken to eradicate it. It's parasitic and by living off the host plant, it many times will kill that plant. We were fortunate in that it was found in an area of our garden that largely contains annuals. Fortunate in that it's recommended that you remove the infected plants and I'd much rather lose an annual than a perennial, of course.
Yesterday, when I blogged about the wicked and disgusting Iris borers, Romie made the comment, "It's always something." So true. And today's something is dodder. Never heard of it? Neither had I. I'd never seen it prior to this summer either.I'd noticed orangey threadlike tendrils had been winding themselves around some of the Asclepias curassavica (Scarlet Milkweed) seedlings for a couple of weeks now. I tried pulling them off, but it wasn't as easy as it looked. Just when I thought I had it all, there was some more. And it was so tiny and so tenacious!This morning, I posted a description of what we had on Twitter and asked if anyone knew what it could be. I hadn't yet taken a photo of it, so I thought it might take awhile before someone recognized what I was talking about. But Annie in Austin knew right away: "Hope it's not dodder: http://bit.ly/3rmbZd."
Her link took me to the Missouri Botanical Gardens website, which I've used before in a number of ways, including their Kemper Center for Home Gardening. The information there confirmed that we did indeed have dodder (Cuscuta spp.).
Romie and I pulled the tendrils off and in the end, only had to pull a few seedlings before we got it all (as far as we know). This year hasn't been the best for growing annuals at Our Little Acre. Most of them should be way taller and blooming their heads off by now. Many of them aren't and this Asclepias is one of them. We just need some good hot weather and some rain!
The dodder wasn't having any problems growing though. We'll monitor that area, because I fully expect it to return. I'm checking out the possibility of using Preen® pre-emergent herbicide in the soil there to prevent its return, because that's something we have on hand. Glyphosate (Round-Up®) will kill the plant itself, but I'd rather prevent it from growing in the first place and don't really like using Round-Up® if we don't have to.
UPDATE: I received a response from the makers of Preen® today-
Currently we do not have a garden product that will prevent Dodder weed seeds from germinating, nor do we have a product that will kill existing Dodder. We recommend you contact your local cooperative extension agency for their advice/recommendations on controlling this weed as eradication is almost impossible.
Thank-you & Have a good day!
Lebanon Seaboard Corporation
Photo of Asclepias curassavica in bloom was taken 8-23-08. If you click on the photo, you'll see a larger version and you might also see something besides flowers!