Q: Several years ago I planted six houttuynia plants at the bottom of a slope that also contained English ivy. Now the houttuynia is taller than the ivy and stinks like the dickens. Is there something I could spray on the houttuynia while it is taller than the ivy that would kill it but not ivy?
A: Houttuynia, also known as chameleon plant, is a garden thug. Once planted, it is almost impossible to eradicate. But since it is taller than the ivy, you might find success by wiping glyphosate (Roundup, etc) on its leaves using an old towel wrapped around the end of a garden rake. Spray chemical on the towel until it is damp and then swipe it over the infested slope. Otherwise, no chemical is smart enough to tell the difference between chameleon plant and English ivy.