It takes a lot of work — and a lot of heat — to maintain the tallgrass prairie at Fernwood Botanical Garden and Nature Preserve.

Each spring, half of the 5-acre prairie is burned in order to stimulate growth for the upcoming growing season and control the spread of invasive species.

The prairie burn normally occurs on the last Saturday of March, but this year Fernwood conducted the burn on Sunday, April 17, due to less-than-ideal weather conditions in late March.

“It was too wet so we ended up waiting,” said Fernwood Horticulturist Ralph Reitz. “I was afraid that we would miss a good window to burn, but it was nice and dry. In fact it was a pretty hot day and we had a really hot fire, which is good.”

Because of the heat, spectators got to see a rarity at the prairie burn — pillars of flame extending several feet into the air.

“It was so hot that the fumes would burst into flame,” Reitz said. “That does a good job of killing, especially woody plants, because most of their investment is above the ground. Most trees give up the ghost pretty quickly.”

Reitz said the prairie contains approximately 100 species of plants, including warm season perennial grasses native to southwestern Michigan.

The Buchanan Township Fire Department conducted the burn, using a mowed fire lane around the prairie, water and backfires to keep it contained.

Reitz said the perennial grass roots run deep enough that the fire does not damage them.

The controlled burn, he said, removes dead plant material from previous year’s growth and unlocks nutrients from the dead plants, making them available for the new year’s growth.

Burning also makes it easier for Fernwood staff to manage invasive species, which are tracked in by various means, including foot traffic and during mowing.

Reitz said one of the main problem weeds they deal with is crown vetch, which is often planted by highway departments and other agencies as a stabilizer for embankments.

“It tends to be very difficult to eradicate,” he said. “That is probably our biggest challenge and that is one reason why we burn.”

For more information about Fernwood, visit fernwoodbotanical.org.