LaRoche ended an 0-for-15 start to the season by going deep in consecutive at-bats, Werth and Ian Desmond also homered, and the Nationals overcame some sloppiness on the basepaths and from their bullpen to open an early interleague series by holding on to edge the Chicago White Sox 8-7 on Tuesday night.
The Nationals have 10 homers in their past three games.
"We've got a really balanced lineup. That's something that we have that most teams don't. It's tough on matchups. It's tough on pitchers, really," Werth said. "There's not really an easy spot in our lineup."
He and LaRoche each hit a two-run shot off Jake Peavy in the sixth, an inning after Desmond went deep.
LaRoche added a solo homer in the eighth off Matt Thornton, Chicago's fifth pitcher. LaRoche had missed the previous two games with a back muscle problem.
"You get into the second week of the season," LaRoche said, "that's never a good feeling to look up there and not have a hit."
Said Nationals manager Davey Johnson: "I wasn't worried about him."
Werth also tacked on an RBI single off Matt Lindstrom for an unearned insurance run in the seventh, part of a stretch in which the Nationals scored in each of their last five innings. That allowed Washington to hold on even though Alex Rios took closer Rafael Soriano deep for a two-run shot with two outs in the ninth. Soriano got Paul Konerko -- who homered earlier -- to fly out to end it and record his third save in four chances.
"Wasn't pretty," Johnson said. "Whew."
Bryce Harper and Nationals starter Gio Gonzalez, who left after five innings and didn't factor in the decision, were thrown out by Rios from right field while trying to stretch early singles into doubles.
Craig Stammen (2-0) got the win despite allowing a run and three hits in the sixth.
Johnson insisted he isn't nervous about his bullpen.
"It's early in the year. Guys are not throwing like I know they're capable of," he said. "Soriano -- he's not exactly where he needs to be, as far as I'm concerned. He's mostly just throwing fastballs and locating fastballs. He hasn't used much of his other stuff."
But a good offense masked other problems, including Desmond connecting off Peavy (1-1) leading off the fifth on a humid evening with the first-pitch temperature at 81 degrees.
"That's a good lineup and they're going to work you," Peavy said. "It was hot and humid. I mean, I was pouring sweat, losing a lot of fluid and was going through hydration stuff."
With the score 2-all, Denard Span started the sixth with a double. That's when Peavy got a mound visit from bullpen coach Bobby Thigpen, filling in for pitching coach Don Cooper, who missed the game because he went to the hospital with a stomach illness.
Thigpen returned to the dugout, and Werth promptly sent Peavy's next pitch to left for his third homer.
Peavy struck out Harper, but walked Ryan Zimmerman, bringing up LaRoche, who hit a 1-1 pitch near the 402-foot sign in straightaway center to make it 6-2.
"Ran out of gas and didn't have much there," said Peavy, who gave up six runs and nine hits in 5 1/3 innings. "Jayson Werth kind of knew what we talked about there on the mound. That pitch wasn't bad and he looked to do damage, and not hit the ball the other way, and he got us. I didn't have much there for LaRoche and he put a good swing on it."
Konerko answered for the White Sox, hitting a three-run homer off Tyler Clippard in the seventh to pull Chicago to 6-5.
But the Nationals kept adding runs.
"Up and down the lineup," Desmond said, "we're doing great."
White Sox 2B Gordon Beckham left in the third inning with nerve irritation in his left wrist; he said he felt pain after fouling off a ball while batting in the second. He was replaced by Angel Sanchez. Beckham said he got X-rays that showed "there's no structural damage; there's no break." ... With Thigpen filling in for Cooper, bullpen catcher Mark Salas handled Thigpen's duties. ... With no DH in an NL park, and a lefty starter on the mound for Washington, White Sox slugger Adam Dunn was out of the lineup -- a rest day he didn't really want. Asked about the different DH rules in baseball's two leagues, Dunn said: "I do have an opinion. But I'd like to keep it to myself, because I like my job." He was on deck when the game ended.