How to Grow Black and Blue Sage

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Black and Blue Sage

Salvia guarantica 'Black and Blue'

shrub

Black and Blue Sage is a striking ornamental shrub known for its deep blue-black calyces and vibrant blue flowers that bloom prolifically throughout the growing season. This tender perennial reaches 3-4 feet tall and wide, making it ideal for borders, containers, and Mediterranean gardens. It attracts hummingbirds and butterflies while requiring minimal maintenance once established.

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Example Black and Blue Sage timeline · Pittsburgh, PA (Zone 6b)

  1. Plant Black and Blue Sage

    Around Apr 17

    Near Pittsburgh's average last spring frost.

  2. Tend & protect

    Late spring–summer

    Watering, feeding, and pest-watch reminders.

  3. Harvest Black and Blue Sage

    Around Jun 16

    ≈ 60 days after planting

Sample dates for Pittsburgh, PA. Sign up to get exact Black and Blue Sage dates for your own zip code.

Growing Conditions

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Sun: Full sun, 6-8 hours daily for best flowering and compact growth
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Water: Moderate watering; allow soil to dry slightly between waterings. Drought-tolerant once established. Reduce watering in winter.
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Spacing: 24 inches
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Days to maturity: 60-90 days to significant flowering; blooms continuously from spring through fall
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Planting depth: Plant transplants at same depth as nursery pot; surface sow seeds lightly as they need light to germinate

Soil

Type: Well-draining loamy or sandy soil
pH: 6.5-7.5
Amendments:
Perlite or coarse sand for drainage Compost for organic matter Avoid heavy clay or waterlogged soils

Growing Zones

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Thrives in zones 8-11; grown as an annual in cooler zones or brought indoors for winter

8a 8b 9a 9b 10a 10b 11a 11b

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Growth Stages

1

Seedling

2-3 weeks

Tiny seedlings with first true leaves emerging; very delicate and requiring high humidity.

Keep soil consistently moist but not waterlogged. Provide bright light without direct sun. Maintain 70-75°F temperature.

2

Juvenile Vegetative

3-4 weeks

Plant develops multiple sets of true leaves, becoming stockier; reaches 4-6 inches tall.

Gradually increase light exposure. Begin hardening off if grown indoors. Can pinch stem tips to encourage bushiness.

3

Establishment

4-6 weeks

Plant develops branching structure and deeper root system; 12-18 inches tall with dense foliage.

Plant outdoors after last frost. Water regularly but avoid overwatering. Apply balanced fertilizer monthly.

4

Flowering

Late spring through fall frost

First flower spikes appear with distinctive black calyces and bright blue tubular flowers; blooming escalates.

Increase phosphorus with bloom-boosting fertilizer. Deadhead spent flowers to encourage continuous blooming. Ensure full sun.

5

Mature/Sustained Bloom

6-8 months until first frost

Full shrub covered with continuous flower spikes; plant reaches mature height of 3-4 feet.

Maintain moderate water and monthly feeding. Cut back by one-third in late summer for second flush of flowers. In zones 8-9, prune in late winter.

Companion Planting

Plan your garden →

Plant with:

Avoid planting near:

Moisture-loving plants like astilbe or hostas Plants requiring consistent moisture such as hydrangeas Aggressive spreaders in confined spaces

Common Pests

  • Spray with insecticidal soap or neem oil; increase air circulation; use yellow sticky traps for monitoring.

  • Mist foliage regularly to increase humidity; spray with water to dislodge; use neem oil if severe.

  • Ensure good air circulation; avoid overhead watering; apply sulfur dust or fungicide if needed.

  • Spray with strong water stream; use insecticidal soap; encourage natural predators like ladybugs.

Uses

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Landscape Accent and Border Plant

Ornamental

Black and Blue Sage is prized as an ornamental specimen for its striking two-tone flower color and extended bloom period. It serves beautifully in Mediterranean, cottage, and contemporary gardens as a focal point or massed planting. [source]

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Hummingbird and Pollinator Magnet

Wildlife

The tubular blue flowers are irresistible to hummingbirds, butterflies, and bees, making it invaluable for pollinator gardens. It provides nectar from late spring through the first frost. [source]

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Cut Flower Arrangement

Household

The dramatic flower spikes last well in fresh arrangements, providing long-lasting color and interest to indoor displays. Their unique bicolor appearance adds visual intrigue to bouquets. [source]

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Herbal Tea

Culinary

Like many Salvia species, Black and Blue Sage leaves can be dried and steeped into a mild herbal tea with subtle flavor. This traditional use capitalizes on the plant's aromatic properties. [source]

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Traditional Herbal Properties

Medicinal

Salvia guarantica has been used in traditional South American herbalism for various wellness purposes. Some species of Salvia contain compounds studied for potential antioxidant and cognitive support benefits. [source]

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

Harvest Tips

While not typically harvested for consumption, deadhead spent flower spikes regularly to promote continuous blooming throughout the season. Flowers are long-lasting in arrangements if desired. Cut back the entire plant by one-third in late summer for rejuvenation and a second flush of flowers. In zones 8-9, prune again in late winter before new growth emerges.

Fun Facts

  • 🌱 The cultivar name 'Black and Blue' perfectly describes the flower's stunning appearance: the calyces (outer sepals) are deep black-purple while the tubular petals are brilliant blue, creating a striking bicolor effect.
  • 🌱 Salvia guarantica is native to South America, particularly Argentina and Paraguay, where it thrives in warm, dry conditions—explaining its preference for full sun and well-draining soil.
  • 🌱 This plant can be overwintered indoors in cooler zones by bringing potted specimens inside before the first frost and placing them in a bright, cool location (50-60°F), then moving back outside after the last spring frost.

Gardening Terms

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

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