Houttuynia can be very strong, and you might not be able to tolerate a whole tablespoon. Like all herbs, it should be ramped up gradually. I opted for tincture, since I could start at the smallest dose possible. Gradually I got up to 1 full dropper twice a day for houttuynia tincture from dried leaves (or 1/4 dropper if using fresh leaf tincture). Fresh leaves produce the strongest tincture. Dried leaves are better for tea, but are suitable for tincture if that's the only form you can get/make.
1st Chinese Herbs has dried. You can order live plants from Richters. I'm a bit too far north for it to be happy here, so I just used dried leaf tincture.
Tincture making is pretty easy. I do it high tech (Vitamix to powder herbs, vacuum suction to press), but you can do it low tech (buy powdered herb or tincture whole herb, hand press). I use organic grain alcohol from Alchemical Solutions (you might need to get an alcohol permit from your state first). Everclear is another option. You could use any vodka from the store, but some herbs do best with a specific alcohol percentage. You do need to add water if you're using Everclear or organic grain alcohol. There's pretty good instructions in Buhner's books. These are good resources on making standardized tinctures. I let my tinctures go for 4 weeks. If you use any vodka (something <190 proof), they should go for 6-8 weeks.
bearmedicineherbals.com/an-introduction-to-tinctures.html/oldwaysherbal.wordpress.com/2013/12/15/making-weight-to-volume-tinctures/