Special lawn is a spring attraction

This spring, try letting one of your customer’s lawns grow, unmowed, until around June 1. The grass might be 8 or 10 inches tall by then, and there will undoubtedly be dandelions or some other non-turfgrass species poking up even higher than that. The results are unlikely to impress anyone, but that’s exactly the maintenance program followed on one special lawn at the Missouri Botanical Garden (www.mobot.org), and there, the results are impressive. So much so that people come just to see that overgrown patch of grass. What makes the difference? Thousands of crocus bulbs.

No preemergent weed control can be used on the Crocus Lawn, but once the show of color is over and the area is finally mowed, it can be maintained much like any other lawn, though aeration with tines is avoided.
Photos courtesy of Missouri Botanical Garden.

Crocus Facts

Crocus are easily grown in average, medium, well-drained soils in full sun to part shade. Plant corms about 2 to 3 inches deep and 3 to 4 inches apart in the fall. If planted in the lawn, foliage should be left unmowed until it yellows (about six weeks after bloom). Naturalizes well. Plants go dormant by late spring.

Noteworthy Characteristics:
Large flowering crocuses are among the most widely grown early spring bulbs (actually corms). Each corm produces several upright, cup-like, purple to white flowers with darker purple feathering or stripes on the outside. Typically grows 4 to 6 inches tall. Basal, grass-like leaves. Blooms in early spring shortly after snowdrops (Galanthus). Flowers close at night and open up in the morning, but usually remain closed on rainy/cloudy days. Many cultivars of this species have been developed.

Problems:
No serious insect or disease problems. Squirrels, mice and other rodents can be problems. Squirrels seem particularly adept at locating, digging up and eating newly planted corms.

Uses:
Brings early spring bloom to the landscape. Mass in lawns, under trees or in sunny woodland areas. Large sweeping drifts can be spectacular. Also may be grouped in rock gardens, in front of shrubs, along walks or in various other small areas around the home.
Source: Missouri Botanical Garden.

“I’d guess there’s about 30,000 out there, maybe there’s more than that,” says Pete Hitch, turf manager at Missouri Botanical Gardens. The stunning flowers are actually part of what is called the Crocus Lawn, and make their appearance each spring to add color and visual interest not often found in a standard sea of turfgrass.

Crocus are more commonly seen in lawns in Europe and Asia, where these plants are native. Their use at the Missouri Botanical Garden shows that, with the right maintenance approach, crocus can bring an Old World charm to lawns in the U.S., as well. Make no mistake, the Crocus Lawn, a mixture of cool-season grasses, requires a dramatically different approach than the rest of the turf at the Missouri Botanical Garden, says Hitch. “We mow it short in the fall, to normal lawn height, but then it won’t be mowed again until around June 1,” he says.

The crocus begin to bloom in late February and March (sometimes coming up through the snow) before the grass begins to grow. This gives them a chance to show off their color before being overtaken by the turf. “In fact, they’re probably done blooming by the time the grass really begins to grow,” says Hitch. Even after the show of color is complete, he holds off mowing the lawn, even as its height begins to rise. “The crocus and grass grow together for a while, but we don’t mow right away because the crocus leaves replenish the bulbs for the next year, they put food back down into the bulb.”

Some of the crocus get to be 6 inches tall, but others remain shorter. “They grow a lot like tulips,” says Hitch. “After the tulip flowers, the leaf replenishes the bulb, and then next year you have more tulips. If you cut the leaves off the tulips, you won’t have much in the way of tulips the following year.”

After a while, the leaves on the crocus turn brown and sluff off. “That’s when I know it’s OK to mow,” Hitch says. At that point, the grass is about 8 inches tall, or more. “It’s bordering on looking like a field by then,” he adds. “One year the grass got so tall we found a wild turkey nested in there.”

Two 62-inch Ferris zero-turn mowers are used to power through the hay-like grass. “We set the deck as high as we can the first pass and then lower it after that. After we mow it, we rake the area by hand and put the clippings in our compost pile,” Hitch explains. Removing the clippings is important to avoid building up heavy thatch on the Crocus Lawn. He says no particular disease or pest problems that have arisen from letting the turf get much higher than typical lawn height.

The Crocus Lawn spreads over about 18,000 square feet. Each of the last two years, 15,000 new crocus bulbs have been installed in the lawn. The horticultural staff at Missouri Botanical Garden recommends use of several types of C. tommasinianus and C. vernus in crocus lawns, reporting that these varieties have shown the best success in coming back year after year. Conversely, they recommend the various forms of C. chrysanthus in lawn use. Fewer than half the crocus bulbs are lost each year, and Hitch says the average life expectancy is about three or four years out of each bulb. Continually planting bulbs helps keep the crocus coming up strong each spring, and that’s important to visitors. “They’re a big attraction for the people who visit here,” says Hitch.

The Crocus Lawn is not irrigated, though occasionally an aboveground sprinkler will be set up if conditions get too dry and hot. That’s just one difference in the way the area is maintained. Most importantly, it’s critical that no weed control be sprayed on the Crocus Lawn in the spring. “We can’t put out anything preemergent, or that would keep the crocus from coming up,” says Hitch. Once the lawn is mowed, he can put out weed control products if needed. He also tries to avoid spring fertilization in that section of the property, preferring to wait until late summer/early fall to put down a light amount of fertilizer.

The Crocus Lawn at Missouri Botanical Garden features eye-catching color each spring thanks to the tens of thousands of crocus bulbs planted there. The grass is not mowed until around June 1 in order to give the plants time to take up energy for the following year.

Aeration is one maintenance practice that’s avoided on the Crocus Lawn. “The bulbs are down about 2 or 3 inches. A lot of times the tines that won’t go down that deep, but we can’t take that chance, because they might,” says Hitch.

There are a total of 20 acres of turf at the Missouri Botanical Garden (which totals 79 acres), much of it found in small, intricate gardens. “There are also a lot of specimen trees where we have to be careful not to damage the root systems,” says Hitch. As a result, most of the mowing is done with smaller equipment. In addition to the two Ferris zero-turns, the four-man turf crew utilizes 48 and 52-inch walk-behinds and a Honda 21-inch push mower. “We have two rose gardens with tight areas where we really need the push mowers,” he adds. “We also use a number of string trimmers to edge everything.”

The garden is open year-round except for Christmas Day, so maintenance must be scheduled around the public. “We open at 9 a.m., so we try to get as much as possible done before then,” says Hitch. “We try to get the most visited areas first thing in the morning, and beat the people to those areas.”

In the summer and fall, the Crocus Lawn looks just like any other turf area at Missouri Botanical Garden, so visitors during much of the year have no idea what surprise lies beneath the surface. Those lucky enough to visit in the spring know exactly how eye-catching the colorful crocus can be.

Patrick White is a freelance writer and editor who has covered every aspect of the green industry in the past 13 years. He is based in Middlesex, Vt., and is always on the lookout for unusual stories.