Last year, Chip Taylor underestimated the public’s interest in milkweed, the wildflower — a “weed,” some would say — that attracts monarch butterflies.

He thought a few dozen enthusiasts would come to Monarch Watch’s first milkweed sale. No need to set up more than a couple of card tables, he figured.

Wrong.

“It was incredible. We probably had 250 people show up,” said Taylor, director at Monarch Watch and a professor of ecology and evolutionary biology at Kansas University. “We couldn’t keep up.”

That won’t happen at this year’s sale, which is being combined with a spring open house.

“We’re prepared this time,” he said. “We’ll have six to eight people here at all times. And we’ll have more plants than we did last year.”

The sale and open house will be from 8 a.m. to 3 p.m. Saturday at Foley Hall on KU’s west campus.

Open house events include:

• Observation tents with live butterflies.
• Live displays featuring local and exotic insects.
• Monarch videos.
• Tagging demonstrations.

6News video: Butterflies tagged at annual Monarch Watch (9-16-03) Plant sale to benefit butterflies (5-23-03) KU Monarch Watch

• An active honey bee observation hive.
• Presentations on brown recluse spiders.

“We won’t be able to give away caterpillars like we did at the fall open house,” Taylor said. “The timing, unfortunately, isn’t right for that.”

At least 1,600 plants will be for sale, including tropical, swamp and butterfly-bush milkweed. Other butterfly- and hummingbird-friendly plants will be available.

Proceeds from the sale will be used to underwrite Monarch Watch research and outreach efforts.

Based at KU, Monarch Watch is a nationally recognized, nonprofit program dedicated to promoting the study and conservation of Monarch butterflies.

Taylor said the Monarch population suffered severe losses last winter.

“Down in Mexico, two storms in January wiped out 70 percent of the over-wintering population,” Taylor said. “It looks like what’s happening is that with global warming, Pacific air masses are moving in, causing it to rain. And then when it clears off, it freezes in a hurry.

“The butterflies don’t have a chance to dry out, which leaves them pretty much defenseless.”

A similar storm wiped out nearly 80 percent of the population in 2002.

Taylor said this year’s spring migration had been slow.

“The numbers returning are quite low,” he said. “We’re concerned, but at this point we’re not worried because this is a species that has the capacity to rebound fairly quickly.”

He added, “We’ll know a lot more in another month.”