Botanical Name: Phlox subulata ‘Emerald Blue’

Common Name: Creeping Phlox, Moss Phlox

Hardiness Zone: Perennial in Most Climates (USDA Zones 3–9)

Size: 4–6" Tall × 18–24" Spread

Growth Habit: Low-Growing, Mat-Forming, Spreading Habit

Sunlight: Full Sun (Best Flowering); Tolerates Light Shade

Soil: Prefers Well-Drained Soil; Tolerates Sandy or Rocky Soils

Water Needs: Low to Moderate; Drought Tolerant Once Established

Bloom Season: Early to Mid-Spring

Fertilizer: Minimal; Light Feeding in Early Spring if Needed

Features: Soft Blue-Lavender Flowers, Evergreen Needle-Like Foliage, Excellent Erosion Control, Deer Resistant

Uses: Ideal for Ground Cover, Slopes, Rock Gardens, Edging, and Over Walls

Patent: ❌ Not Patented

Propagation: ✔ Propagation Allowed

See our complete Creeping Phlox Plant Guide for full care details.

More About Creeping Phlox ‘Emerald Blue’

‘Emerald Blue’ is one of those Creeping Phlox Varieties that quietly earns its place in the garden year after year. When it comes into bloom in early Spring, it creates a sweeping carpet of soft blue-lavender flowers that feels cool, calm, and almost ethereal against the warming landscape. At peak bloom, the foliage is nearly invisible beneath the dense layer of blossoms, giving the impression of a solid sheet of color laid gently across the ground. The hue leans toward a true blue-lavender rather than pinkish purple, which makes it especially valuable when you’re trying to introduce cooler tones into a Spring planting scheme. In bright sunlight, it almost shimmers, while in softer evening light it takes on a more muted, powdery tone.

Unlike some of the hotter pink varieties, ‘Emerald Blue’ brings a sense of balance and restraint. It softens bold color combinations and acts as a visual “cool down” plant in mixed beds. After flowering, it transitions seamlessly into a tight, evergreen mat of fine, needle-like foliage that stays neat and compact through the growing season and into Winter. The texture is uniform and refined, giving you structure even when it’s not in bloom. It’s particularly useful in poor, rocky, or sloped soils where drainage is excellent. Rather than fighting tough conditions, this plant seems to thrive in them.

Why We Like It (Our Trials)

In our testing grounds here in the SC Upstate, ‘Emerald Blue’ has consistently impressed us with its durability and steady growth habit. We’ve planted it in full, blazing sun on exposed slopes where soil dries quickly, and it has established without hesitation. It spreads at a controlled, manageable pace that is fast enough to fill in gaps efficiently, but never so aggressive that it crowds out neighboring plants. Once rooted in, it requires very little attention beyond occasional trimming after bloom to keep it looking sharp. We’ve also found it holds up well through temperature swings in early Spring, which can sometimes stress other flowering groundcovers.

This variety has also become one of our go-to options for creating movement in the landscape. We love using it along retaining walls where it can cascade gently over the edge, almost like a waterfall of soft blue. It’s equally effective lining walkways, softening hard edges, or stabilizing slopes where erosion used to be a concern. Deer typically leave it alone in our area, which adds to its reliability. It pairs beautifully with spring bulbs like daffodils and tulips, weaving around their stems without overwhelming them. Every season when it blooms, it delivers that cool-toned, tranquil spring moment that makes the entire garden feel refreshed and alive again.

Creeping Phlox ‘Emerald Blue’ vs. Other Creeping Phlox

Emerald Blue delivers a cooler, more tranquil color experience than Emerald Pink, favoring soft blue tones over deep, dramatic pinks. Compared to Amazing Grace, Emerald Blue provides more color presence while maintaining a refined, balanced look. Emerald Blue is the strongest choice when a calming, cohesive Spring palette is desired.

Compared to Spring® Scarlet, Emerald Blue is intentionally subdued, offering balance rather than intensity. And next to Candy Stripe, Emerald Blue provides a uniform, grounded appearance instead of visual pattern and contrast. For gardeners looking to create peaceful, natural-looking plantings with consistent color, Emerald Blue is the clear choice.