Mountain Mint (Pycnanthemum species) is a native perennial prized for its aromatic foliage and ability to attract beneficial insects. Companion planting with Mountain Mint is an effective strategy for creating a thriving, low-maintenance ecosystem. Selecting partners that complement Mountain Mint’s unique traits helps extend the pollinator season and manage its vigorous growth habit. This approach maximizes the ecological benefit of the plant while maintaining visual harmony and ease of care.
Understanding Mountain Mint’s Growth Profile
Mountain Mint is an adaptable plant, generally thriving in full sun, which encourages the most prolific flowering, though it can tolerate partial shade. It is not overly particular about soil, growing well in moist, well-drained conditions but also tolerating clay, rocky, or sandy soils once established. The plant’s primary characteristic dictating companion selection is its growth habit, which varies by species.
Species like Pycnanthemum muticum (Blunt Mountain Mint) are often described as clump-forming, but they spread robustly by rhizomes and can become aggressive in optimal conditions. Other varieties, such as P. virginianum, are more pronounced spreaders, behaving like a tall groundcover. While Mountain Mint is not as invasive as culinary mints (Mentha species), its vigorous nature means companions must be equally robust to avoid being overwhelmed.
Choosing Companions for Ecosystem Function
The primary ecological service of Mountain Mint is its attraction to a wide variety of pollinators, including bees, wasps, and butterflies. To create a complete ecosystem, select companions that provide resources when Mountain Mint’s mid-to-late summer bloom is absent. Early spring bloomers, such as Wild Geranium (Geranium maculatum) or Foamflower (Tiarella cordifolia), offer nectar when beneficial insects first emerge, extending the foraging season.
Companions should also attract different types of pollinators, particularly those that cannot access Mountain Mint’s small, shallow flowers. Plants with deep, tubular flowers, like Wild Bergamot (Monarda fistulosa) or Anise Hyssop (Agastache foeniculum), are excellent for attracting hummingbirds and larger butterflies. These additions ensure the garden supports a broader spectrum of wildlife. Furthermore, some companions offer pest-deterring qualities, such as planting Alliums like Chives, which can help repel common garden pests.
Choosing Companions for Structure and Aesthetics
Companions are selected to provide structural and visual contrast to Mountain Mint’s fine texture and upright, sometimes floppy, habit. Selecting plants based on height and form helps manage the appearance of a mass planting, preventing it from looking like an undifferentiated green mass. Structurally stiff plants, particularly warm-season native grasses like Little Bluestem (Schizachyrium scoparium) or Switchgrass (Panicum virgatum), stand up well against the vigor of the mint.
These tall, upright companions provide a contrasting vertical element and can subtly act as a visual barrier, containing the perception of Mountain Mint’s spread. Plants with large, bold foliage, such as Joe Pye Weed (Eutrochium species) or larger Coneflowers (Echinacea species), offer a coarse texture that offsets the fine, silvery-green leaves of the mint. Color contrast is achieved by pairing the mint’s white to pale-pink flowers and silvery bracts with vibrant blooms. This combination creates a dynamic visual display.
Practical Tips for Planting the Companion Bed
Successful long-term planting relies on strategic placement and proactive maintenance to manage the mint’s vigorous nature. When installing plants, allow ample space (a minimum of one to two feet) between Mountain Mint and its companions so rhizomes can spread without choking out neighbors. For smaller gardens, a more controlled approach involves planting Mountain Mint within a bottomless container or using a sturdy root barrier to physically limit its lateral spread.
The mixed planting bed requires well-drained soil, but preparation should ensure adequate moisture for the mint, which prefers medium-to-moist conditions. Managing Mountain Mint’s spread also involves aggressive cutting back; pruning in late spring or early summer (the “Chelsea Chop”) encourages bushier growth and reduces height. Deadheading companion plants is also important, as this prevents excessive self-seeding, which could lead to an overcrowded bed.