There are, however, many beneficial potato plant companions. Plant cabbage, corn and beans around potato hills to improve their growth and taste. Growing horseradish as a companion plant for potatoes is said to make potatoes resistant to diseases. Petunias and alyssum also attract beneficial insects to potato plants.Click to see full answer. Herein, what plants should not be planted together? Here are some plants that do not grow well when planted together: Potatoes. Potatoes have problems with many plants. Beans and Peas. Broccoli and Cauliflower. Cabbage and Cauliflower. Asparagus. Brussel Sprouts. Kohlrabi. Carrots. Subsequently, question is, what should not be planted next to onions? Bad Plant Combinations Beans, beets, cabbage, carrots, cauliflower, corn, cucumbers and strawberries make good neighbors — as long as you plant the onions, garlic, leeks and shallots elsewhere. Peppers do well with carrots, eggplant, onions, parsley and tomatoes, but do not plant kohlrabi anywhere near them. In this manner, what grows well with cabbage? These plants are good neighbors for cabbage: Aromatic herbs: Chamomile, hyssop, thyme, rosemary, dill, peppermint, spearmint, sage, oregano. Garden edging: Yarrow, marigolds. Root vegetables: Onions, beets, celery. What should not be planted with tomatoes? Bad Companions for Tomatoes Cabbage (Brassica) family: All relatives of cabbage stunt the growth of tomato plants (including broccoli, Brussels sprouts, cabbage, collards, cauliflower, kale, kohlrabi, rutabaga, and turnip). Corn: The corn earworm is the same as the tomato fruitworm. (Also known as the cotton bollworm.)