Bring 4 cups water, the lemon juice, and sugar to a boil in a medium saucepan. Remove from heat; cover. Cut a round of parchment paper that has a diameter 1 inch greater than that of pan; set aside.

Core apples. Peel golden ones; using 1 lemon half, rub flesh. Squeeze juice from remaining half into hollows of red apples.

Using a mandoline or sharp knife, cut all apples crosswise into thin (less than 1/8 inch) slices. Transfer to syrup; shake pan to coat slices. Place parchment directly onto surface of apple mixture. Let syrup cool completely, about 40 minutes.

Cut slices into semicircles. Stack 1 red apple slice on top of 1 golden slice, with cut edges nearest you. Wrap slices together into a cone shape to form a "bud."

Stack two more slices. Placing them slightly above base (to create a staggered appearance), wrap them around bud. Repeat, wrapping until rose is about 2 inches in diameter. Make 9 roses total. Reserve leftover peeled slices for garnish.