Enlarge / The cut flowers could pay for themselves and even turn a profit. (credit: Margi Rentis)

Flowers grown on inexpensive floating platforms can help clean polluted waterways, over 12 weeks extracting 52 percent more phosphorus and 36 percent more nitrogen than the natural nitrogen cycle removes from untreated water, according to our new research. In addition to filtering water, the cut flowers can generate income via the multibillion-dollar floral market.

In our trials of various flowers, giant marigolds stood out as the most successful, producing long, marketable stems and large blooms. Their yield matched typical flower farm production.

Why it matters

Water pollution is caused in large part by runoff from farms, urban lawns, and even septic tanks. When it rains, excess phosphorus, nitrogen, and other chemicals wash into lakes and rivers.