How to Grow Agapanthus 'Blue Storm' Northern Star

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Agapanthus 'Blue Storm' Northern Star

Agapanthus africanus 'Blue Storm' Northern Star

flower

A compact ornamental perennial that produces striking deep blue flowers arranged in spherical umbels atop tall stems. This cultivar is renowned for its hardiness and ability to thrive in cooler climates compared to standard Agapanthus. The plant features strap-like green foliage and creates stunning focal points in gardens during mid to late summer bloom.

When should you plant Agapanthus 'Blue Storm' Northern Star in your zone?

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Example Agapanthus 'Blue Storm' Northern Star timeline · Pittsburgh, PA (Zone 6b)

  1. Plant Agapanthus 'Blue Storm' Northern Star

    Around Apr 17

    Near Pittsburgh's average last spring frost.

  2. Tend & protect

    Late spring–summer

    Watering, feeding, and pest-watch reminders.

  3. First Agapanthus 'Blue Storm' Northern Star blooms

    Mid-to-late summer

    Before the first fall frost (≈ Nov 8)

Sample dates for Pittsburgh, PA. Sign up to get exact Agapanthus 'Blue Storm' Northern Star dates for your own zip code.

Growing Conditions

☀️
Sun: Full sun, 6-8 hours daily minimum; tolerates partial afternoon shade in hot climates
💧
Water: Moderate watering during growing season; allow soil to dry between waterings. Once established, relatively drought tolerant. Reduce watering in winter dormancy.
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Spacing: 18-24 inches apart for mature spread inches
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Days to maturity: 180-365 days (flowers in year 2-3 from young plants)
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Planting depth: Crown at or slightly above soil surface; do not bury crown

Soil

Type: Well-draining loamy to sandy soil
pH: 6.0-7.0
Amendments:
perlite or coarse sand for drainage compost for organic matter gravel for container growing

Growing Zones

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Zones 4-10, with exceptional cold hardiness for a Northern Star selection

4a 4b 5a 5b 6a 6b 7a 7b 8a 8b 9a 9b 10a

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Growth Stages

1

Establishment

First year

Young plant with developing strap-like foliage emerging from soil. Root system expanding in soil.

Water regularly to establish deep roots. Protect from extreme cold first winter. Mulch around base but avoid touching crown.

2

Vegetative Growth

Spring through early summer

Mature clump of arching green foliage expanding outward. Plant develops more leaves and increases in diameter.

Water moderately during dry spells. Feed with balanced fertilizer in spring. Remove any dead or damaged leaves.

3

Flowering

6-8 weeks, typically July-September

Tall flower stalks emerge from foliage center, each topped with spherical umbels of deep blue flowers. Blooms progress from bottom to top of flower head.

Stake tall varieties if needed in windy locations. Deadhead spent flowers to encourage extended blooming. Water consistently during flowering.

4

Seed Development

September-October

Flowers fade; seed pods form in spherical clusters. Foliage begins to yellow and decline as plant enters dormancy.

Allow some flowers to remain for seed formation and winter interest if desired. Otherwise, remove seed heads. Reduce watering.

5

Winter Dormancy

November-March

Foliage dies back completely or persists in diminished form depending on climate. Plant enters rest period.

Minimal water needed. Apply 2-3 inch mulch layer in zones below 6 for winter protection. Avoid disturbing crown.

Companion Planting

Plan your garden →

Plant with:

Avoid planting near:

Aggressive spreading perennials Plants requiring consistently moist soil Competitive shallow-rooted plants

Common Pests

  • Increase humidity with regular misting; use insecticidal soap if severe; strong water spray to dislodge

  • Remove with rubbing alcohol on cotton swab; treat with neem oil or insecticidal soap for infestations

  • Scrape off manually; treat with horticultural oil during dormancy or active growing season

  • and

    Remove by hand; use copper barriers or slug traps; encourage natural predators

Uses

🍳

Ornamental garnish

Culinary

While not edible, the striking blue flower umbels are occasionally used as temporary table decoration or for special event floral arrangements. [source]

🎨

Cut flowers and dried arrangements

Craft

Long-lasting cut flowers ideal for fresh arrangements. Seed heads dry naturally and can be preserved for winter craft projects and dried bouquets. [source]

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Landscape focal point

Household

Serves as a striking specimen plant, border accent, or massed planting for dramatic summer color. Excellent for Mediterranean, contemporary, and pollinator gardens. [source]

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Pollinator attraction

Wildlife

Flowers attract bees, butterflies, and other beneficial insects. Provides important mid to late summer nectar source when many plants have finished blooming. [source]

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Traditional herbal use

Medicinal

In South African traditional medicine, Agapanthus has been used for various purposes, though modern clinical evidence is limited. Not recommended for internal use without professional guidance. [source]

This is not medical advice. LizPlants is not a medical resource. Always consult a qualified healthcare professional before using plants medicinally.

Harvest Tips

Agapanthus is an ornamental; cut flowers for arrangements when fully open. Cut stems at base with sharp knife in early morning. Flowers last 1-2 weeks in vase. Allow seed heads to persist on plant for winter interest or remove promptly to redirect energy to root system development. For Northern Star cultivars specifically, the deep blue coloring is most intense in cooler climates.

Fun Facts

  • 🌱 Agapanthus 'Northern Star' represents a significant breeding achievement, making these African lilies reliably hardy in zones as cold as 4, where standard Agapanthus would not survive winter without protection.
  • 🌱 The name 'Agapanthus' derives from Greek words 'agape' (love) and 'anthos' (flower), literally meaning 'flower of love.' In Victorian times, these plants symbolized love and were popular in grand estates.
  • 🌱 The deep blue coloring in 'Blue Storm' varieties intensifies in cooler climates with adequate sunlight, making Northern climates ideal for achieving the most vibrant flower color.

Gardening Terms

New to gardening? Learn about terms used in this guide:

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