How to Grow Black and Blue
iNaturalist
Black and Blue
Salvia guaranitica 'Black and Blue'
shrubBlack and Blue is a tender perennial sage cultivar known for its striking dark purple-black calyxes and brilliant blue flowers that attract hummingbirds and pollinators. It's a semi-woody, upright shrub that blooms prolifically from summer through fall. This dramatic ornamental is popular in mixed borders and container gardens for its exceptional color contrast and extended flowering season.
When should you plant Black and Blue in your zone?
Get a personalized planting timeline — when to start seeds, transplant, and harvest — based on your USDA zone and local frost dates. Free to start.
Example Black and Blue timeline · Pittsburgh, PA (Zone 6b)
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Plant Black and Blue
Around Apr 17Near Pittsburgh's average last spring frost.
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Tend & protect
Late spring–summerWatering, feeding, and pest-watch reminders.
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Harvest Black and Blue
Around Jun 16≈ 60 days after planting
Sample dates for Pittsburgh, PA. Sign up to get exact Black and Blue dates for your own zip code.
Growing Conditions
Soil
Growing Zones
Find your zone →Zones 8b-11; grown as an annual or container plant in colder zones
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Get my Black and Blue timeline →Growth Stages
Seedling/Transplant
2-4 weeksSmall plants with opposite, lance-shaped green leaves emerging from soil; no flowers yet
Keep soil evenly moist; provide bright light; pinch tips to encourage branching if leggy
Vegetative Growth
4-8 weeksPlant develops multiple stems and expands leaf canopy; increasingly bushy habit with no flowers
Maintain consistent moisture; apply balanced fertilizer every 2-3 weeks; pinch growing tips to promote fuller shape
Bud Formation
2-3 weeksFlower buds appear at stem tips; dark purple-black calyxes become visible before flowers open
Increase phosphorus fertilizer to encourage blooming; maintain regular watering; support tall stems if needed
Flowering
8-16 weeks (June-November in most climates)Brilliant blue flowers emerge from dark purple-black calyxes in dramatic spikes; plants reach full height of 3-5 feet
Deadhead spent flowers to encourage continuous blooming; water during dry spells; stake if needed in windy locations
Fall/Winter Decline
Varies by zoneFlowering slows with temperature drop; foliage may darken; plant becomes dormant in frost-prone areas
Reduce watering; cut back dead wood in spring; in colder zones, dig up and store indoors or treat as annual
Companion Planting
Plan your garden →Plant with:
Avoid planting near:
Common Pests
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Spray with neem oil or insecticidal soap; increase humidity around plants; rinse leaves with water
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Use yellow sticky traps; spray with insecticidal soap or neem oil; ensure good air circulation
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Apply sulfur or fungicide at first sign; improve air circulation; avoid overhead watering; remove infected leaves
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and
Remove by hand; use copper barriers; apply diatomaceous earth; eliminate hiding spots
Uses
Edible Flowers
CulinaryThe bright blue flowers are edible and make striking garnishes for cocktails, salads, and desserts. They have a mild sage flavor with slight herbal notes. [source]
Hummingbird & Pollinator Magnet
WildlifeBlack and Blue is highly attractive to hummingbirds, bees, butterflies, and other pollinators throughout its extended blooming season. It provides essential nectar and pollen when few other flowers are available in late summer and fall. [source]
Cut Flowers & Arrangements
HouseholdThe unique dark calyx-blue flower combination makes striking fresh or dried arrangements. Cut stems last well in water and continue to bloom for extended periods. [source]
Herbal Properties
MedicinalLike other Salvia species, Black and Blue contains essential oils with potential antimicrobial and anti-inflammatory properties. Leaves can be steeped into tea, though the cultivar is primarily grown ornamentally. [source]
Dried Flower Crafts
CraftHang-dry the flower spikes for long-lasting botanical decorations, wreaths, and pressed flower projects. The dark calyxes retain color and visual impact when dried. [source]
This is not medical advice. LizPlants is not a medical resource. Always consult a qualified healthcare professional before using plants medicinally.
Harvest Tips
Black and Blue is grown for ornamental flowers rather than harvest. Deadhead spent flower spikes regularly to promote continuous blooming throughout the season. Cut flowers last 1-2 weeks in a vase. For propagation, collect seed from mature flower heads in late fall, or take softwood cuttings in spring.
Fun Facts
- 🌱 Black and Blue is a cultivar selection from Salvia guaranitica, a species native to South America (Paraguay, Argentina, and Brazil), and was selected for its exceptional color contrast between the nearly-black calyxes and vivid blue flowers.
- 🌱 The dark purple-black calyxes that give this plant its name are actually modified sepals that persist long after the blue petals drop, extending the visual interest of the plant for weeks.
- 🌱 This cultivar has become increasingly popular in ornamental horticulture since its introduction and is grown as an annual or tender perennial in temperate climates, thriving in containers that can be moved indoors before frost.
Gardening Terms
New to gardening? Learn about terms used in this guide:
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