05/01/2024
Argh! Now here is something a dahlia grower never hopes to see. The big bump on this dahlia tuber is crown gall: a bacterial infection that will damage the health and productivity of this plant, and that may spread to my other dahlias if I plant this tuber. Of course, I won’t plant it: into the garbage it goes, along with the other tubers in the same bag, and I’ll Lysol the heck out of everything it touched.
Crown gall (and its even-uglier stepsister, leafy gall) is pretty rampant in dahlia tubers bought from places like Wal-Mart, Costco, and Eden Brothers, which import their tubers from the Netherlands. But any tuber can be infected. I got this one from a US-based small grower whom I *know* to be extremely careful; I’m sure the bump wasn’t there when she mailed me this tuber last month. That’s why - now that it’s almost planting time here in the Boston suburbs - you’ll want to inspect all your dahlia tubers before you plant them.
Lots of folks are trying out dahlias for the first time this year, and I’m thrilled about that! Dahlias are amazing plants, but they come with a *lot* of health issues (unfortunately, they get viruses too!) and they need super-careful treatment. I’m planning to do a series of posts on them in the coming months - but for now, the American Dahlia Society is a great resource for info on gall, viruses, and best handling practices. Check them out - and look over your tubers for weird bumps and growths before you plant them in your garden! If you see an out-of-place bump like this one - or a bunch of fused-together shoots coming out of one tuber, which is symptomatic of leafy gall - throw that tuber in the garbage (not the compost) and sterilize everything that touched it.