Companion planting is partnering certain plants together, ultimately to help keep certain pests at bay, and often with the benefit of bringing pollinators to your garden. While some plants work to repel harmful insects, there are certain types that can also lure insects away from plants you may wish to protect.
Allium (garlic, chives) keeps aphids and slugs away. Planting Allium will help keep aphids off of rose bushes and vegetable plants such as peppers, tomatoes, cabbage, and carrots. The flowers are lovely and will also attract bees and nectar loving pollinators.
Marigolds, which were also previously mentioned to repel mosquitos, also help fight off aphids and nematodes, and can even help deter rabbits. They are great interspersed throughout a garden filled with tasty veggies.
Dahlias will not only come back year after year, but they are also useful thanks to their ability to keep nematodes at bay.
Lavender will help deter mice and rabbits, as well as moths, flies, and mosquitos.
Nasturtium is edible and beautiful, and has been said to help keep some flies away from plants. It is also commonly referred to as a trap plant, as it supposedly lures aphids to it, keeping the insects away from other plants.
Sweet alyssum, as noted by its name, will offer a lovely sweet scent to any garden. The tiny flowers will attract helpful insects, including predatory wasps that will prey on other insects that may damage your garden.
Most importantly, research beforehand what your garden needs, as not all plants are suited as companions. As an example, although Dill works well with cabbage, it can attract insects that will harm tomato plants. There are many companion plants out there, and a little investigating will help determine what is best suited for your gardens.