Preheat the oven to 375°F (190°C) and gather the ingredients.
In a small bowl, whisk together the oil, thyme, marjoram, salt, and pepper. Zest the lemon to yield about 1 teaspoon of peel and stir it into the herb oil. Cut the lemon into quarters and set aside.
Tuck the chicken wings behind the bird to secure them, and fasten the drumsticks together with kitchen twine or a skewer. Place the chicken breast-side up on a rack set in a shallow roasting pan.
Brush the herb oil all over the chicken. Put the lemon quarters into the chicken cavity. Insert a meat thermometer into the thickest part of the inner thigh, avoiding bone.
Roast the chicken, uncovered, for 45 minutes.
After 45 minutes, arrange the halved potatoes, carrots and green beans around the chicken in the pan. Brush the vegetables and the chicken with any remaining herb oil.
Return the pan to the oven and continue roasting, uncovered, for an additional 30 to 45 minutes, or until the thermometer registers 180°F (82°C) and the thigh juices run clear when pierced.
Remove the chicken from the oven and let it rest for about 15 minutes before carving. Discard the lemon pieces from the cavity.
Carve the chicken, transfer to a platter, arrange the roasted vegetables around it, and serve with the pan drippings.