Phlox is cherished for its vibrant blooms and sweet fragrance. Companion planting involves growing different plant species together to foster mutual benefits. This practice enhances garden health and visual appeal, supporting a thriving phlox display.
Why Companion Plant with Phlox
Companion planting offers specific advantages that directly benefit phlox. Certain plants deter common phlox pests, potentially reducing the need for chemical interventions. Other companions attract beneficial insects, such as ladybugs and parasitic wasps, which naturally control harmful insect populations. Some plant pairings can improve soil conditions or nutrient availability, creating a more favorable growing environment for phlox root systems. Thoughtful companion planting also contributes to a more aesthetically pleasing garden, with complementary textures and bloom times that extend visual interest. This symbiotic relationship supports phlox by mitigating disease pressure and promoting robust growth.
Key Considerations for Companion Plant Selection
Selecting appropriate companion plants for phlox begins with understanding shared environmental requirements. Sunlight exposure is a primary factor; phlox generally thrives in locations receiving at least six hours of direct sunlight, so companions should share this preference. Water requirements must also align, as consistent moisture is beneficial for phlox, making drought-tolerant plants less suitable partners unless specific watering zones are managed. Soil preferences are equally important; phlox prefers rich, well-drained soil, so plants requiring sandy or heavy clay conditions are not ideal.
Considering the mature size of companion plants, both in height and spread, helps prevent overcrowding and competition for resources. Staggering bloom times ensures continuous visual appeal in the garden, providing color before, during, and after the phlox flowering period. Evaluating growth habits, such as aggressive spreading or deep rooting, helps maintain balance within the planting area and prevents one plant from overwhelming another.
Recommended Companion Plants for Phlox
Many plants complement phlox, contributing to its health and garden aesthetics. For perennial pairings, coneflowers (Echinacea purpurea) offer a striking contrast with their daisy-like blooms and similar sun and soil needs. Their sturdy stems provide support and attract pollinators. Shasta daisies (Leucanthemum x superbum) make excellent partners, providing a classic white backdrop that highlights phlox colors while sharing similar growing conditions. Daylilies (Hemerocallis) can be planted alongside phlox, offering varied bloom times and foliage textures, though their root systems should be given adequate space.
Regarding annuals, zinnias bring vibrant color and attract butterflies, thriving in the same sunny, well-drained spots as phlox. Their upright growth habit complements the phlox mounds. Cosmos, with their airy foliage and delicate flowers, pair well, adding a soft visual element and attracting beneficial insects.
For subtle additions, herbs like dill or parsley attract predatory insects that prey on phlox pests, while their foliage provides a textural contrast. Low-growing groundcovers such as creeping thyme (Thymus serpyllum) suppress weeds around the base of phlox, conserving soil moisture and providing a fragrant carpet. Small ornamental grasses, such as ‘Hameln’ dwarf fountain grass (Pennisetum alopecuroides ‘Hameln’), offer a fine texture contrast and movement without overshadowing the phlox.
Arranging Your Phlox and Companions
Thoughtful arrangement ensures visual harmony and plant health. Adequate spacing between phlox and its companions is crucial to allow for mature size and promote good air circulation, which helps prevent fungal issues like powdery mildew.
Creating visual layers by placing taller plants behind or in the center of beds, with phlox in the mid-ground, and shorter companions or groundcovers in front, adds depth and interest. Consider complementary color combinations; for instance, cool-toned phlox can be paired with warm-toned companions for vibrancy, or similar hues for a serene effect. Ensuring each plant receives sufficient sunlight and air flow prevents competition and supports robust growth. Allowing enough room for future growth will prevent plants from becoming overly dense and stressed.
Plants to Avoid Near Phlox
Certain plants can hinder phlox growth or increase its susceptibility to issues. Aggressive spreaders, such as mint (Mentha) or some aggressive groundcovers like vinca, should be avoided as they quickly outcompete phlox for nutrients and space, overwhelming its root system.
Plants highly susceptible to powdery mildew, like bee balm (Monarda didyma) or squash, can act as disease reservoirs, increasing the risk of infection for phlox. Avoid placing phlox near plants that have vastly different water or soil requirements, such as those preferring very dry or consistently boggy conditions, as this creates an unsuitable environment. Tall, heavy feeders like sunflowers deplete soil nutrients and cast too much shade, disadvantaging sun-loving phlox. Black walnut trees (Juglans nigra) produce juglone, a natural chemical toxic to many plants, including phlox, so keep them far apart.