CORVALLIS, Ore. — To support pollinators, many people are creating eco-friendly spaces around their homes, including replacing grass lawns with flowering plants.
That’s no easy task, according to Carolyn Breece, Oregon State University Extension Service faculty research assistant in the Oregon State Honey Bee Lab. Since 2016, Breece has studied flowering lawn substitutes. The results show that transitioning from an all-grass lawn to a flowering lawn is challenging.
"The first year it was beautiful," Breece said. "After the end of the first year, things didn’t look so well in terms of pollinator plant diversity. I think if you’re going to put the effort into pollinator habitat, you’d be better off spending the effort on growing pollinator plants at the edges of a lawn or eliminating lawn altogether."
Testing different seed mixtures
Over a series of trials, Breece used a variety of seed mixtures, including:
- Perennial ryegrass, the most common grass west of the Cascade Range
- Fleur de Lawn eco-mix
- A bee meadow mixture
- Several mixes of flowering species such as yarrow, alyssum, baby blue eyes and chamomile with varying percentages of clover
The bee meadow mixture included sunflower (Helianthus), black-eyed Susan, blanket flower (Gaillardia), California poppy, tickseed (Coreopsis), lupine, borage and phacelia.
"The whole idea was to plant a flowering lawn that provided pollen or nectar," Breece said. "You see English daisies in lawns and they’re really cute, but they don’t provide much for the bees. We tried to find flowering plants that would bloom at short height so they can be mowed and have the look of the great American lawn but still have resources for pollinators. It’s hard to find plants that flower that short that would also fit into a lawn."
Clover and yarrow show promise
In the end, the biggest hurdle was getting the plants to grow in the presence of grass, which is highly competitive.
"The two primary plants most successful in combination with turf grass are clover and common yarrow," said Alec Kowalewski, OSU's Grover Family Endowed Sustainable Urban Landscapes Specialist. "Both do very well. Yarrow is very drought-tolerant and clover is a nitrogen-fixer, which means it provides nitrogen to the other plants, eliminating the need for fertilizer."
Yarrow looks attractive in a lawn, Breece added, but doesn’t flower well when mowed short. Clover, on the other hand, is a workhorse. Over time it can shade out other plants, leaving a simple mixture of clover and perennial ryegrass. This allows the look of a traditional lawn with the added benefits of clover: food for pollinators and nitrogen for surrounding plants.
But even clover needs minimal irrigation to survive. A lawn — whether a traditional mat of green or one designed to support pollinators — requires maintenance, Kowalewski said.
"People ask me all the time how to have a perfect, emerald green lawn without any maintenance," he said. "It’s not going to happen. Even pollinator and eco-lawns need to be watered, mowed and fertilized, just not as much as traditional turf."
Low-input lawns offer alternatives
Tom Cook, retired Oregon State Extension turf specialist, developed the Fleur de Lawn mixture in the mid-1980s when he was looking for alternatives to traditional turf. His work focused on maintenance rather than pollinator support, but many of the parameters were the same. Cook also showed that clover is the most resilient of grass substitutes.
"My goal was to find a mowable groundcover that looked somewhat like grass lawns but required less input than regular lawns," Cook wrote. "Specifically, I wanted a lawn that required mowing, less irrigation, less fertilizer and was competitive with common weeds that invade under-fertilized, drought-stressed grass lawns."
Cook’s mixture of perennial and Kentucky ryegrass, yarrow, clovers and English daisy is still sold as Fleur de Lawn. Once installed, owners either love it or hate it, he said. Usually, those who dislike it are the ones who don’t maintain it.
"Most landscape contractors I have talked to like them," he wrote. "As one fellow told me, he makes money installing them and a couple of years later makes money replacing them with conventional grass lawns. The point is that low-input lawns are not intended to replace grass lawns. They are intended to provide an alternative for people who don’t want or can’t maintain a conventional lawn."
Previously titled Eco-friendly lawns require forethought to attract pollinators
