Senecio Mandraliscae 'Blue Chalk Sticks'

Blue Chalksticks / Blue Finger / Blue Straws

Botanical Name: Senecio mandraliscae 'Blue Chalk Sticks'
Family: Asteraceae
Origin: South Africa (Eastern & Western Cape)
Plant Type: Evergreen succulent (low shrub/groundcover)

Overview

A standout foliage plant for Adelaide, ‘Blue Chalk Sticks’ forms dense, bluish-silver fingers that create a bold, modern look year-round. It thrives in SA’s heat and coastal conditions, shrugging off drought once established. Flowers are incidental—grow it for the colour and texture; remove blooms to keep the plant tight and tidy.

Key Features

• Mature Size: 0.3–0.6 m H × 0.6–1.2 m W (clump-forming, spreading)
• Growth Rate: 20-40 cm per year under good conditions
• Foliage: Powdery blue, cylindrical “chalk” leaves; neat, architectural habit
• Flowers: Small white clusters in summer; not showy (can be removed)
  
• Seasonal Interest: Evergreen silver-blue structure; brightest in cooler months
• Wildlife Value: Flowers provide some nectar for bees/beneficials if left on
• Tolerance: Drought- and coastal-tolerant; wind-tolerant; light frost to about –2 to –3 °C if kept dry; avoid waterlogging
• Planting Density: Mass planting 5–7 plants per m²; borders/edges space 30–50 cm apart
• Pet Friendly: No — ingestion can be harmful to pets/livestock

Where It Works Best

• Sunlight: Full sun (best colour) to light part shade
• Soil: Free-draining sandy or gravelly loam; on heavy clay, plant on mounds/raised beds and add grit; avoid winter-wet spots
• Water Needs: Establishment: 2 deep soaks/week for 8–12 weeks. Established: deep soak every 10–14 days in summer (more often in heatwaves); little to none in winter if dry
• Maintenance: Mulch with gravel; clip off spent flower stems; tip-prune straggly shoots in late winter; easy to propagate from cuttings
• Lifespan: 5-10+ years
• Climate Zones: Suited to temperate & Mediterranean SA gardens, including coastal areas
• Soil pH: Broadly tolerant (slightly acid to alkaline)

Landscape & Design Ideas

• Coastal/xeriscape borders, gravel gardens and contemporary courtyards
• Mass as a low, weed-suppressing carpet; dramatic contrast with dark greens and purples
• Superb in large pots; pairs well with kangaroo paws, westringia and lomandra

Why You Will Love It

Instant, water-wise impact: that cool silver-blue tone makes everything around it pop. Tough, low-mess and coast-ready, it keeps its crisp form in Adelaide with minimal watering and a quick tidy once a year.