Botanical Name: Plumbago auriculata ‘Imperial Blue’ Common Name: Blue Plumbago, Cape Leadwort Hardiness Zone: Perennial in USDA Zones 9–11 (Grown as an Annual or Tropical Accent in Colder Climates) Size: 6–10' Tall × 6–10' Spread Growth Habit: Shrubby, Spreading, Semi-Vining Habit Sunlight: Full Sun to Partial Shade Soil: Well-Drained Soil; Adapts to a Wide Range of Conditions Water Needs: Moderate; Drought Tolerant Once Established Bloom Season: Late Spring through Fall Fertilizer: Light Feeding in Spring; Avoid Excess Nitrogen Features: Intense Sky-Blue Flower Clusters, Heat & Humidity Tolerant, Long Bloom Season, Deer Resistant Uses: Shrub Borders, Foundation Plantings, Espaliers, Large Containers, Tropical Landscapes

Patent: ❌ Not Patented Propagation: ✔ Propagation Permitted

More About Plumbago ‘Imperial Blue’

Plumbago ‘Imperial Blue’ is a classic tropical shrub prized for its brilliant sky-blue flower clusters that bloom continuously from late spring through fall. Few landscape plants offer true blue color at this scale, making plumbago a standout wherever it’s planted.

The plant develops a loose, flowing habit that can be grown as a large shrub, trained along walls or fences, or allowed to cascade naturally. In warm climates it becomes a permanent landscape feature; in cooler regions it is often used as a dramatic seasonal accent.

Why We Like It (Our Trials)

In our trials, ‘Imperial Blue’ has been an exceptionally reliable heat performer, thriving in full sun, humidity, and poor soils where many shrubs struggle. Once established, it tolerates drought well and continues blooming with minimal care.

We especially appreciate its design impact. The soft blue flowers contrast beautifully with green, bronze, or dark foliage and pair effortlessly with whites, pinks, and tropical textures.

‘Imperial Blue’ vs. White Plumbago

Compared to white plumbago, ‘Imperial Blue’ offers a stronger focal presence and richer color saturation.

White plumbago excels as a blending or brightening plant, while ‘Imperial Blue’ is best used as a statement shrub or anchor in tropical and summer landscapes. For gardeners seeking a long-blooming, heat-loving shrub with unforgettable blue flowers, Plumbago ‘Imperial Blue’ is an outstanding choice.