HornwortText Box: HORNWORT (Ceratiphyllum demersum) Many tiny branched stems with whorls of bristle like foliage. Does not need to be planted in soil, just floats at the bottom of the pond. Hornwort will have at least 5 heads per clump Weather permitting Hornwort is shipped from April through July. Call for availability early and late in the season. We do our best to be aware of the plants not allowed to be shipped to your state, however, the responsibility is the buyers if your not sure check with your local USDA Office.