Vegetables favored by the upper classes include onions, garlic and leeks - the more flavorful, less hearty types. While the lower classes ate more lettuce, cabbage, and carrots.
Also, during this time, vegetables were sometimes called "herbs" or "potherbs" and were grouped together with herbs such as fennel and parsley and edible flowers such as violets. Leafy plants were often called wortes.
Tomatoes, yams, artichokes, green beans, corn, and colored peppers were not yet available.
Some of the other vegetables that were eaten in this period:
Medieval Cookery Blog