Many sun loving perennials go well with phlox, such as ornamental grasses, agastache, rudbeckia, coreopsis and other plants. Pick plants that will complement the color of your phlox as well as the color of other plants you place around the phlox.
Before purchasing plants or rearranging your garden, it is important for you to decide what you would like to see in your garden. How would you like it decorated? Would you like a minimal amount of plants or a lot of plants? How tall would you like your plants? What colors would you enjoy?
As phlox has bright flower clusters, other plants around the phlox should be a little duller in vibrancy not to compete or distract from the beauty of the phlox’s color. The exception would be with white phlox, which has no color, or if you have a very small amount of phlox.
Phlox grows to anywhere between 15-48 inches high depending on both the variety of the phlox and the location where you live. Most varieties reach between 24-36 inches. When choosing plants to place near and around your phlox, make sure that to place taller plants behind the phlox, so you don't obscure it from view. Tall ornamental grasses are perfect for this, as it gives a nice backdrop to the color of the phlox.
Likewise, smaller plants should be placed in front or around the phlox. It is important to know how you would like to place your plants, whether you want to create a border or a specific type of plant or have a smorgasbord or colors and varieties.
If you have a small garden with a weaker soil, consider using plants that do not require as many nutrients as the phlox. This will allow it to gain and maintain the nutrients that it needs without competing with other plants.
Also, by planting a few insect repellent plants in the area, you could help save your plants from potential pest damage.
A List of Good Companions
One of the best companions to phlox are other colors and varieties of phlox itself, but others can add beauty to the plant’s surroundings. These plants are agastache, Echinacea, hermerocallis, ornamental grass, coreopsis, penstemon, rudbeckia, Euonymus, Gaillardia, Nepeta, Perovskia, Physocarpus, Salvia, Sedum, and Weigela.
These are all plants that enjoy the same amount of sun as the phlox, but do not distract or take away from its beauty. It is important to add plants that will need the same type of care as the phlox.
However you decorate your garden, you should do it in a way that you will enjoy. Though there are things that appeal to many, if you enjoy a specific combination of plants, you should try it out and see if it works.