Long Leaf Opera, which staged its first production a dozen years ago in Durham, will disband at the end of the current season following the death last month of co-founder and artistic director Randolph Umberger, said co-founder and musical director Benjamin Keaton.

"It's been tough," said Keaton, who launched Long Leaf with Umberger in 1998. "Everybody's been doing what they can. But without Ranny, I can't do it by myself. So in June it will end.

"If the right person were to come along, I would consider giving it to them. But I can't do it myself, and I would have to know they would carry it on and do it as well as we did."

The company will present the final performance of its annual holiday opera, "Amahl and the Night Visitors" tonight at The ArtsCenter in Carrboro.

Long Leaf will hold its scheduled annual vocal competition, which regularly draws singers from all over the nation, and will stage its last show, the world premiere of the winner of its one-act competition, "A Shipwreck Opera," at The ArtsCenter in early June.

Umberger had been diagnosed with leukemia, Keaton said, but the disease appeared to be under control, and Umberger was set to direct this year's production of "Amahl and the Night Visitors," which Long Leaf has presented eight times since 2001.

Umberger went into Duke Hospital for chemotherapy last month, but almost immediately developed bleeding in the brain, Keaton said. His condition plummeted. Within days he was gone.

"It was incredibly sudden," Keaton said. "He was stable, and then within a few days he was critical."

Umberger's death stunned the company just as it was in the process of preparing for this year's "Amahl."

"It's so sad, and it's been very hard on everyone," said Carl Johnson, a company member and volunteer marketing coordinator for Long Leaf. "But Long Leaf is a family, and we're all pulling together to help each other get through this. We have a great company, and it's a wonderful show. It's been very challenging, especially for Ben, but he's a true leader."

Keaton and Umberger, both of whom had long been deeply involved with the Durham Savoyards, founded Long Leaf in order to bring a little-known facet of opera to Triangle audiences. The company, virtually alone among opera companies nationwide, presented songs exclusively written and sung in English, mostly by American composers.

"There were companies that would sprinkle the occasional work in English in among all the standard warhorses, but we were the only company in America doing works only in English," Keaton said. "We also knew that American composers were being neglected, and we focused on bringing their works to light. So we were doing something special. We've presented more world premieres than any company in North Carolina, and we became a member of Opera America, which gave us a prestige we hadn't previously had."

The company was always based in Chapel Hill, but from the start it has had strong ties to Durham as well, and over time it became a truly Triangle-wide troupe, presenting operas on stages from UNC's Memorial Hall to Durham's Carolina Theatre to N.C. State's Stewart Theater.

Umberger was senior professor of theater at N.C. Central, and for the first several years, Long Leaf staged almost all of its productions in Durham, mostly at the Carolina.

In 2005, Long Leaf made the East Chapel Hill High auditorium its home base. The company launched its national vocal competitions the following year, and in 2007 began both the one-act competition and a summer opera festival at UNC.

Shortly before Umberger's death, Long Leaf formed a partnership with The ArtsCenter.

"I had heard a rumor that Ranny and Ben were thinking about not doing this season because production costs were so high," said Jeri Lynn Shulke, artistic director of The ArtsCenter Stage. "I'd worked with Ranny, and I called him and said, 'If we could give you a place to perform, would you be interested in working with The ArtsCenter?' He and Ben loved the idea, which would save them some costs, and we were excited about it."

They met and worked out the details of the season.

"They let me know Ranny was going into the hospital, but they seemed quite optimistic," Schulke said. "And then, in a matter of days, he had passed. It was shocking for everyone, but it's a great group, and they've pulled together to make things as smooth as they could be. The show is great. It's really, really good."

Keaton said he has heard that at least one party is interested in the possibility of taking on the company after this season, but no discussions have been held. For his part, he said, he'll be sad to let Long Leaf go, but at 76 he's ready to pursue some other things.

"It's not like I'm going to stop doing anything," he said. "I'm also a composer, and while I've been working with the opera I haven't had time to compose. I'm going to continue doing what I want to do. It's time to move on."