There are many plants, herbs, and flowers which are effective at repelling some detrimental insects with their pungent odors that can disguise the scent of the anticipated host plant from marauders. There are ornamental plants which attract beneficial insects needed for pollination and increased crop yields (courtesy: zerowastehomestead.com).
By: John Green, Texas Certified Expert Gardener, Bridge City, TX
Last week our discussion centered on how plant selections can improve gardening efficiency. We can expand gardening efficiency further if we include ‘companion’ planting into the mix. Companion planting is a gardening approach which groups different plants together which are beneficial to one another by deterring pests, attracting beneficial insects, improving soil health, or increasing plant growth.
Plants have basic requirements which must be satisfied for optimal growth. This begins with good quality soil (friable), abundant sunlight, nutrient availability (proportional macro- and micronutrient accessibility), and sufficient moisture to ensure gardening success. Another aspect of gardening (plant selection) should include (as it is often overlooked) plants which grow well together. Plants are like people…some plants are ‘friendly’ and compatible with one another and some are not. In fact, some plants disdain for each other will become negatively impactful (combative) to the detriment of both!
Companion Plants
There are many plants, such as herbs which are effective at repelling some insects with their pungent odors, disguising the scent of the anticipated host plant. Examples of how companion planting can assist gardeners: Dill and basil interplanted with tomatoes can offer protection against tomato and tobacco hornworms, marigolds are literally ‘golden’ when cultivated with many plantings as they repel beetles and nematodes, and Nasturtiums are favored by aphids, insects which will concentrate on them rather than other plants. Carrots, dill, parsley, and parsnip attract beneficial insects and pollinators such as ladybugs, spiders, butterflies, and praying mantises which feast on detrimental insect pests.
Blueberries, azaleas, camelias, and hydrangeas thrive in the acidic soils created by pine and oak trees. There are shade-loving plants which search for shelter provided by woodlands and in return offer erosion protection to the forest floor utilizing their shallow roots. Clover and other legumes (members of the pea family) have cooperative relationships with soil bacteria which converts atmospheric nitrogen (from the air) by affixing the nitrogen into the soil (through sequestration) where the soil is enriched becoming fertilizer for other plants.
Combative Plants
These are plants which simply put are not compatible with one another and are often referred to as ‘combatants’. Garlic and other members of the allium family repel numerous pests and are ‘good’ neighbors for many vegetables and blooming plants (which I use throughout vegetable and flower gardens) but beans nor peas enjoy their company…inhibited by allium family members which stunt their growth if planted nearby. Potatoes and beans are inhibited in the presence of sunflowers which are allelopathic, producing a chemical that inhibits growth of plants nearby. There are even family members within groups, i.e. Brassica family with members (cabbage and cauliflower- closely related) which simply don’t like each other…somehow this sounds all too familiar!
By now I’m certain some of you are questioning which vegetables to plant next to each other? What can be planted with tomatoes, pepper or potatoes? When planting vegetables, sunlight requirements for each vegetable must be noted. As plants grow larger, they will provide shade to plants which are vertically challenged (shorter) becoming problematic if the shorter plants require full sun too! You wouldn’t want to plant tomatoes which will grow very tall next to bush beans (which remain low to the ground) since the tomatoes will most likely shade the beans (speaking from experience) as they both have similar sunlight requirements of full sun. Make certain to leave plenty of room between rows when plants have substantially differing heights. In other words, when planting shorter & taller plants together, leave enough space allowing the sun to reach the plants. Shorter plants need to be planted on the southern side of taller plants to ensure they will get full sun at the same time as the taller plants do. The same approach holds true for ornamental annuals, perennials, and shrubs. Make certain the canopy of tall plants doesn’t cast too much shade on shorter plants which require full sun. Successful companion planting is accomplished through observation and recording information obtained throughout the growing seasons. Record plant combinations and harvest results from year to year. Document each season’s learnings by writing information into a garden planner or notebook, then share your experiences with other gardeners so we can all learn!
Companion Planting Chart
Plant Name Companion Plant Combatant Plant Asparagus Tomato, basil Potatoes, onions, garlic, leeks (allium family) Beets Brassica family-broccoli, Brussels sprouts, cabbage, kohl rabi), lettuce, bush beans Beets (Beta vulgaris family) including spinach and chard Brassica family- Broccoli, Brussels sprouts, cabbage, kohl rabi) lettuce, bush beans Celery, beans, beets, dill, onions, lettuce Tomatoes, potato, eggplant, beans, peppers, squash Carrot Tomatoes, leeks, rosemary, sage, chives Coriander, dill, parsnips Corn Beans, cucumbers, peas, pumpkins, melons, zucchini Tomatoes Cucumber Marigolds, nasturtiums, beans, celery, corn, lettuce, dill, peas, radishes Sage, rosemary, broccoli, cabbage, cauliflower Green beans Corn, beans, marigolds, nasturtiums, rosemary, summer savory, cucumbers, peas, potatoes, radishes, Brassica family Beets, allium family (onions, leeks, garlic, shallots) Lettuce Mint, chives, garlic, marigolds, beets, broccoli, beans, carrots, corn, peas, radishes Parsley, brassica family Onion Carrots, beets, cabbage, carrots, lettuce, parsnips, tomatoes, marjoram, savory, rosemary Asparagus, beans, sage, peas Peas Beans, carrots, corn, cucumbers, radish, turnip, mint, chives Garlic, allium family Peppers Basil, onions, spinach, tomatoes Beans, brassica family, carrots, corn, cucumbers, radish, turnip, mint, chives Potato Beans, cabbage, eggplant, peas, corn, marigolds, horseradish Tomatoes Radish Cucumbers, carrots onions, beets, cabbage, kale, lettuce, spinach, squash Hyssop, broccoli, cabbage, cauliflower, turnip, mustard Spinach Lettuce, mustard greens, chard, kale, other leafy greens Potatoes, corn, peppers Squash (summer), Zucchini Beans, peas, radishes, peppermint, dill, parsley, oregano, marigolds Potatoes, cucumbers, pumpkins Squash (winter) Corn, beans, sunflowers, marjoram, dill Radishes, turnip (root crops) Tomato Basil, marigolds, asparagus, carrots, celery, lettuce, parsley, spinach, allium family Cabbage, beets, peas, fennel, dill, rosemary, corn, tomatoes, potatoes
Until next time fellow gardeners, let’s go out and grow ourselves a greener and more sustainable world, one ‘Companion’ plant at a time! Please continue sending gardening questions to: jongreene57@gmail.com.
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