Friends with Benefits
Companion gardening, is the art and science of grouping plants together to assist and enhance each other's greatest qualities, while adding biodiversity and balance to one's garden.
When applied in gardening and agriculture, plants are grown in proximity to one another for pest control, pollination and shelter for beneficial wildlife. It maximizes the use of space and increases plant productivity.
Plants do have a control over the environment, their distinct qualities all contribute to the eco system.
I group companion planting into four categories: Attraction, Repulsion, Amendment and Protection. Here are just a few examples.

Attraction -
Pollinators like bees, birds and butterflies are drawn to flowers for their color, scent and nectar. Pollinators move the pollen from the male part of a plant to the female part, allowing for fertilizing and seed production for plants to reproduce. Plants over time have adapted to become more appealing to pollinators to stay in existence. Flowers that attract birds tend to be colorful and unscented. I've seen a few birds bounce on and off, my larger sunflower heads, bending their stems but not damaging them at all. I love the sound of birds in the garden, and plant extra giant sunflowers, just for them. Bees are enticed by the nectar, color and scent of a flower, although they also do pollinate non flowering plants. Largely accountable for nearly all fruiting and vegetable pollination, bees have small legs that immerse in the nectar. The pollen gets stuck all over their fury bodies, which they transport around from plant to plant. A major key to their success at moving pollen around, making bees the darlings of pollination. Butterflies have ultraviolet light vision, giving them the ability to see patterns and colors humans cannot see. They do not stick around one area for too long, and are long distance travelers. These attributes, allow them to pollinate many flowers in large areas quickly, fleeting in and out spreading pollen and looking pretty while doing so. Moths are also known to be good pollinators, who's brains are wired to catch a flowers essence in the air and track the scent upwind, to the flower. Some moths,that move quickly, hover over a flower, then insert a straw like tongue, into the flower and drink up the nectar, moving pollen to the next flower it feeds from. Other moths that fly slower, do land on flowers, taking their time drinking the nectar and transferring pollen around, as they move from flower cluster to flower cluster. Bats and nocturnal pollinators, without the help of night vision goggles are guided by a flowers scent. They work on flowers that open at night. Creating the seeds of tomorrow is a very important part of nature.
Repulsion
Chemical insecticide sprays are toxic for you and your environment. They build up residue in soil and waterways and affect seed production. By planting insect repelling plants around borders or scattered through veggie patches and garden beds, pests can be confused by scents and colors they don't like and thrown off their tracks, and off your plants. It also encourages you to plant more of a variety of plants. Marigolds work well with most herbs and veggies, and are reported to even keep the vermin away. Citronella, geranium and lemon balm are a few other scented pest repelling plants.
Amendment
Soil conditions predict how healthy your garden will be. Some plants and weeds leech the soil of it's nutrients suffocating plants around them. While others enhance and encourage the best out of their neighbors. Yarrow is a flowering plant that amends the soil by adding nitrogen and enhances the essential oil production in plants grown in its vicinity. Stinging nettle is a weed who's roots dig down to the bottom layers of the soil bringing up its nutrients to the top. It's like Botox for plants. Crowding plants can produce a competition for resources like water and nutrients or planting plants close to each other that just don't match chemically can release toxins into the soil.
Protection
Shade, shelter and support all come under the bracket of protection. Planting under a tree or by a wall gives plants that need shade a great place to grow. Birds and beneficial insects camouflage and seek shelter amongst bushy foliage, under garden debris and rocks. The good guys, like ground beetles feast on insect eggs and larvae and ladybugs feast on aphids. Praying Mantis can camouflage well and are able to catch other insects and even a mouse, in their strong front legs. Support comes in the form of trap plants like nasturtiums. When planted close by to their neighbors, they lure aphids away from valuable plants like roses. They are also good for keeping beetles off cucumber vines and squash plants.
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