How to Grow Larkspur Guinevere
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Larkspur Guinevere
Delphinium ajacis 'Guinevere'
flowerLarkspur Guinevere is a stunning annual delphinium cultivar featuring tall spikes of semi-double flowers in shades of lavender-blue with white centers. This cutting garden favorite grows 3-4 feet tall and produces elegant, densely-packed florets along vertical stems. It's prized for fresh flower arrangements and garden color from midsummer through fall.
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Example Larkspur Guinevere timeline · Pittsburgh, PA (Zone 6b)
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Plant Larkspur Guinevere
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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First Larkspur Guinevere blooms
Around Jun 16≈ 60 days after planting
Sample dates for Pittsburgh, PA. Sign up to get exact Larkspur Guinevere dates for your own zip code.
Growing Conditions
Soil
Growing Zones
Find your zone →Thrives in zones 2-9; prefers cooler climates but tolerates moderate heat
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Seed Germination
2-3 weeksTiny seedlings emerge with cotyledons; very delicate at this stage.
Keep soil consistently moist but not soggy. Provide bright light immediately after sprouting. Germination takes 14-21 days at 60-70°F. Do not cover seeds completely.
Seedling & Early Growth
3-4 weeksFirst true leaves develop; plants are 2-4 inches tall and fairly fragile.
Thin seedlings to proper spacing early. Maintain consistent moisture and moderate temperatures. Harden off transplants gradually if starting indoors before transplanting outdoors.
Vegetative Growth
4-6 weeksPlants rapidly increase in height, developing strong stems and feathery foliage; 12-24 inches tall.
Install stakes or supports early to prevent bending. Pinch tips of young plants to encourage branching if desired. Water regularly and feed with balanced fertilizer every 2-3 weeks.
Flowering
6-8 weeksFlower spikes emerge and progressively open semi-double lavender-blue flowers with white centers from bottom to top.
Deadhead spent lower flowers to encourage continued blooming. Keep plants well-watered; flowering is water-intensive. Cut for arrangements when lower third of spike is open.
Seed Production & Decline
2-4 weeksFlowers fade and elongated seed pods form; foliage yellows and plant senesces.
Allow some flowers to mature into seed pods if you want self-seeding. Stop deadheading final flowers if collecting seeds. Pull plants once they decline significantly.
Companion Planting
Plan your garden →Plant with:
Avoid planting near:
Common Pests
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Remove affected flower buds. Use reflective mulches. Avoid overhead watering in early morning.
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Hand-pick, use copper tape barriers, or apply slug bait. Remove debris where they hide.
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Ensure good air circulation. Avoid overhead watering. Spray with sulfur or neem oil at first sign.
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Increase humidity by misting foliage. Spray with insecticidal soap or neem oil if infestation occurs.
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Spray with strong water stream, insecticidal soap, or neem oil. Attract beneficial insects like ladybugs.
Uses
Edible garnish
CulinaryLarkspur flowers are occasionally used as elegant edible decorations on cakes, salads, and cocktails, though they are more valued for visual appeal than flavor. Always verify that flowers are pesticide-free if consuming. [source]
Cut flowers & arrangements
CraftLarkspur Guinevere is a premier cutting garden flower, prized by florists for tall, symmetrical spikes that work as focal flowers in mixed bouquets, wedding arrangements, and dried arrangements. [source]
Dried flower crafts
CraftThe flowers dry beautifully and retain their color, making them ideal for dried arrangements, wreaths, pressed flower art, and craft projects that last for years. [source]
Pollinator attraction
WildlifeTall flower spikes attract bees, butterflies, and other pollinators, making this plant valuable for supporting beneficial insects in the garden. [source]
Traditional herbal use
MedicinalDelphiniums have been used in traditional herbalism, though modern use is limited due to toxicity. Historical use included dyes and folk remedies; not recommended for internal consumption 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
Cut flower spikes in early morning when the lower third of flowers are open and upper buds are still tight. Cut stems at a 45-degree angle and immediately place in cool water with floral preservative. Remove lower foliage that would sit below the waterline. Larkspurs last 7-10 days in a vase. For dried flowers, hang bundles upside down in a cool, dark, well-ventilated area for 2-3 weeks.
Fun Facts
- 🌱 Larkspur gets its name from the spur-like nectaries on the back of each flower, which resembles a lark's hind claw (larks were common in European gardens when the plant was named).
- 🌱 Delphinium flowers contain delphinidin anthocyanins, the same pigments responsible for their vivid blue color, which are also found in blueberries and are studied for antioxidant properties.
- 🌱 The Guinevere cultivar is named after the legendary Queen Guinevere of Arthurian legend, reflecting the regal, elegant appearance of this tall, stately flower.
Gardening Terms
New to gardening? Learn about terms used in this guide:
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