Answer: Houttuynia is extremely difficult to eradicate because it spreads by underground rhizomes and pulling only the top, or only part of the root system will only serve to give it twice the desire to rebound. The roots grow laterally and are usually deep - 24" or so - and to completely eradicate it you'll need to dig every last fragment of roots out of your garden. I've had success with Round-Up, digging, then Round-Up again. If you're opposed to chemicals, you can kill the plants off by cutting off the tops and then continuing to whack off any stems the roots send up. If you're persistent in cutting down the stems as they emerge and before they develop leaves you'll eventually starve the roots out (they use energy to produce sprouts and recoup that energy when the sprouts develop leaves). I had a whole colony of horsetail (Equisetum) in my yard with the same underground rhizome-type growth habit as Houttuynia. I eventually killed it all off by cutting off each and every sprout as soon as I noticed it breaking through the ground. You can have the same success with Houttuynia if you keep at it. Best wishes with your project!
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