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Nelsons

LENOX -- In Strauss’ "Rosenkavalier," a silver rose becomes the symbol of the betrothal between Octavian and Sophie, who have overcome lovers’ difficulties to reach this amorous and musical pinnacle. At Tanglewood this summer, the operatic moment also carries symbolic value for the Boston Symphony Orchestra and Andris Nelsons.

They have promised themselves to each other.

The presentation of the rose is one of the "Rosenkavalier" excerpts that Nelsons will conduct in a July 12 gala concert celebrating his Berkshire debut as the BSO’s music director-designate. Betrothed now, they will be married in September, when Nelsons formally becomes the BSO’s 15th music director in a line dating back to 1881.

Symbolically, too, the gala unites the two wings of Tanglewood: the parent BSO and the student Tanglewood Music Center Orchestra. The TMC instrumentalists will accompany three singers taking the "Rosenkavalier" roles of Octavian, Sophie and the Marschallin.

The BSO will conclude the milestone evening with rousing works by Rachmaninoff and Ravel. For good measure, the silver rose will also be the decor theme of a gala patrons’ dinner preceding the concert.

The BSO season opens Saturday evening in audience-pleasing fashion with Renée Fleming starring in a program of American classical and popular music. Over the eight weeks, other crowd-pleasers, such as "Candide," and towering works such as Mahler’s Second Symphony will follow. But it is Nelsons’ four programs over two weekends, beginning July 11 -- his longest run with the BSO since his appointment in 2011 --- that hold center stage and a key to the future.

He arrives none too soon. The BSO has been without an active music director at its summer festival for the last six years, and nine of the last 12.

It’s not that Tanglewood has been idle since James Levine conducted the 2008 opening weekend and, sidelined by health issues, never returned. Thanks to in-house leadership and a strong guest-conducting roster, lots of interesting and exciting things have happened on both the BSO and TMC sides.

In fact, it has been interesting to hear the BSO respond to a revolving door of guest conductors, from debut artists to old masters such as Christoph von Dohnanyi and the late Rafael Frühbeck de Burgos. But the sense of a commanding musical presence -- a maestro -- has been missing.

Consider the Levine effect. During his three Tanglewood seasons, he galvanized the BSO and music center with his programming, enthusiasm and vision. He sometimes seemed everywhere at once as he coached students and sat in on classes in addition to preparing and conducting operas and concerts.

The Latvian Nelsons, 35, is a dynamo on the podium. His one previous Tanglewood concert -- a Bach-Brahms program in 2012 -- and a Wagner-Mozart-Brahms program last fall in Boston showed why the BSO staked a claim to him. Electricity seemed to flow from his jittery baton and gestures out to the orchestra, and from there out into the audience.

Still, a music director is more than a conductor. So here is the challenge:

What will Nelsons do in terms of programming? New music and new audiences? Opera? Hiring new players? Dealing with the public, press and patrons? Entering into the musical life of Boston?

And at Tanglewood, involving himself in the training and guidance of students?

This summer will be mostly a getting-acquainted time. Nelsons’ four chosen programs are his only input into the season. For next summer, he has promised three weeks to Tanglewood. The only 2015 details announced so far are a joint BSO-TMCO performance of Mahler’s gargantuan Eighth Symphony in celebration of the school’s 75th anniversary. From Tanglewood, he and the BSO will embark on a European tour.

At this point, Nelsons’ wife, soprano Kristine Opolais, is probably better known to American audiences than he is. She sang in Tanglewood’s Verdi Requiem last summer even though he had to cancel as conductor when he suffered a concussion.

Nelsons joins Alan Gilbert in New York, Gustavo Dudamel in Los Angeles and Yannick Nezet-Seguin in Philadelphia as American orchestras, in a youth-oriented age, turn to youth on the podium. He comes to the BSO from the City of Birmingham Symphony Orchestra in England, where he has been director since 2008, succeeding Simon Rattle. The two cities will share Nelsons during the coming season, when he’ll conduct 10 weeks in Boston.

In 2015-16, he’ll step that up to 12 weeks -- about the same as Seiji Ozawa and Levine. But Ozawa and Levine spent five weeks each at Tanglewood, compared to Nelsons’ three. And Nelsons remains in high demand as a guest on principal European podiums, with ties to the summer Bayreuth Festival in Germany.

For Tanglewood, even a silver rose may have thorns.

After the health problems with Levine, the BSO is clearly betting on youth (and possibly appeal to a younger audience) in its new leader. May this marriage be blessed.