Preheat the oven to 425˚F.
Spread the vegetables out on a heavy, rimmed baking sheet, reserving the rosemary sprigs.
Drizzle with oil and toss around with your hands to coat. Finely chop the rosemary, discarding the stem, and sprinkle it over the veggies along with the salt.
Shake the pan to toss the vegetables around again and roast for 20-25 minutes, stirring once or twice, until the vegetables are tender and golden on the edges.