Companion Planting Flowers and Herbs in the Vegetable Garden

No rule states vegetables and flowers can't mix. A vegetable garden greatly benefits from adding flowers and herbs, not just for aesthetics. Companion planting flowers and herbs with vegetables offers several beneficial features that can protect your vegetables from insect pests and make them more productive.

Companion Plants as Trap Crops

If you can't repel a pest, plant a sacrificial plant to attract them. This is often accomplished with another vegetable crop, such as surrounding cabbage with a trap crop (or catch crop) of collards to attract the diamondback moth.

The pest insect will assemble on the trap crop, which you can then hand-pick and destroy. The most famous flower trap crop is probably nasturtiums, which attract aphids. Nicotiana is also a viable trap crop. Chervil keeps slugs away from your leafy greens, and mustard attracts lygus bugs (tarnish bugs) to keep them away from your apples and strawberries.

Before you plant trap crops, weigh the risk of attracting more of the pest to your garden. The trap crop technique is generally used the year after a pest has significantly damaged your plants. If you can, time it so the trap crop is more mature than the plant it protects.

Pollinators Are Attracted to Nectar-Rich Plants

Vegetables don't always have the showiest flowers. To ensure bees and other pollinators can find your vegetable plants, companion plants should have high nectar concentrations or flowers in shades of blue, yellow, or white. Don't overlook flowering herbs.

Herbs in the mint family, such as oregano and thyme, are particular favorites of bees. Of course, you must stop harvesting a few plants to give them time to set buds and flowers. Some additional choices include cosmos, larkspur, mints (watch for invasiveness or plant in a container), sunflowers, sweet peas, and zinnias.

Some Plants Lure Beneficial Insects

Most insects are not garden pests, and some insects prey on the actual pests. These beneficial insects include ladybugs, lacewings, parasitic wasps, and ground beetles.

As with every other insect, beneficial insects have certain preferences in plants. Companion-plant their favorites, and eventually, beneficial insects will patrol to consume your bad insects. Parsley, dill, coriander, and flowers from the aster family are especially good for attracting beneficial insects.

Repel Garden Pests With Certain Plants

It is still questionable whether some plants repel garden pests or make for a healthier ecosystem. But the topic is worth further study, and it sure can't hurt to try some of these companion pairings if you have a problem in your garden:

• Anise hyssop may repel cabbage moths.
• Borage may repel tomato hornworms.
• Catmint will usually repel aphids, Colorado potato beetles, and squash bugs (verify if it is invasive in your area; it's a fast-grower).
• Geraniums (Pelargonium) should keep away Japanese beetles.
• Pot marigolds usually deter asparagus beetles.
• Sage may repel cabbage moths and carrot rust flies.

Many Types of Plants Promote Biodiversity

Companion planting encourages biodiversity or planting various plants rather than a single monocrop. Diversity helps confuse insect pests by planting things they love with things they won't touch and attracts beneficial insects that can keep pests in check. Whether there is also a symbiotic relationship between different plant species is still being studied.

Hide the Cutting Garden

A bonus of companion planting flowers in the vegetable garden is you can place your cutting garden in a spot with other plants that will not be cut down and look bare. Companion planting vegetables, herbs, and flowers is how the original cottage garden style evolved since sectioning off gardens for specific types of plants was considered a luxury.

So, if you want to plant black-eyed Susan, celosia, salvia, and zinnias in straight rows that will always be halfway cut down, plant them among the vegetables where looks don't count as much as function. Let them do dual duty as cut flowers and pollinator lures.