Candle Larkspur
Delphinium elatum
Delphinium elatum, commonly known as Candle Larkspur, is a stunning perennial known for its tall spikes of vibrant flowers. Native to Europe, this plant adds vertical interest and color to gardens, making it a favorite among gardeners.
Everything it needs
9 essentials at a glance
Watering
Delphinium elatum prefers consistently moist soil, especially during its growing season.
Water deeply once a week, allowing the top inch of soil to dry out between waterings. In hotter months, you may need to water more frequently. Signs of over-watering include yellowing leaves and root rot, while under-watering can cause wilting and browning leaf edges.
Light
This plant thrives in full sun to partial shade, ideally receiving at least 6 hours of direct sunlight daily.
In hotter climates, some afternoon shade can help prevent scorching. It tolerates light shade but may produce fewer flowers in low light conditions.
Soil
Delphinium elatum prefers well-draining, loamy soil with a pH range of 6.0 to 7.0.
A mix of garden soil, compost, and perlite or sand can enhance drainage. Avoid heavy clay soils that retain too much moisture, as this can lead to root rot.
Humidity
This plant enjoys moderate humidity levels, ideally around 40-60%.
To increase humidity, consider misting the leaves or placing a humidifier nearby. Signs of low humidity include browning leaf tips and poor flower development.
Temperature
Delphinium elatum thrives in temperatures between 60-75°F (15-24°C) and is hardy in zones 3-7.
It can tolerate brief periods of heat but may struggle in extreme temperatures above 85°F (29°C). Protect from frost in colder climates.
Fertilizing
Use a balanced fertilizer with an NPK ratio of 10-10-10 or similar, applying every 4-6 weeks during the growing season.
Reduce feeding in late summer and fall. Signs of nutrient deficiency include stunted growth and yellowing leaves.
Pruning
Prune back spent flowers to encourage additional blooming and maintain plant shape.
Use sharp, clean shears to cut stems just above a leaf node. Deadheading should be done regularly to promote new growth.
Repotting
Repot Delphinium elatum every 2-3 years or when it becomes root-bound.
Choose a pot that is 1-2 inches larger in diameter. Signs it needs repotting include roots growing out of the drainage holes and stunted growth. Gently remove the plant from its pot, loosen the roots, and place it in fresh soil.
Propagation
Propagation can be done through seeds or division.
For seeds, sow them in the spring after the last frost, covering lightly with soil. For division, carefully dig up established plants in early spring or fall, ensuring each division has roots and shoots. Replant immediately.
When it's unhappy
Yellow leaves
Why it happens
This can be caused by over-watering or nutrient deficiency.
How to fix it
Check the soil moisture and reduce watering if necessary. Fertilize with a balanced fertilizer to address nutrient issues.
Wilting plants
Why it happens
Wilting can occur due to under-watering or root rot.
How to fix it
Ensure consistent watering, and if root rot is suspected, inspect the roots and repot in fresh, dry soil.
Powdery mildew
Why it happens
High humidity and poor air circulation can lead to this fungal disease.
How to fix it
Improve air circulation around the plant and apply a fungicide if necessary. Avoid overhead watering.
Stunted growth
Why it happens
This can be due to poor soil quality or insufficient nutrients.
How to fix it
Amend the soil with compost and use a balanced fertilizer to promote healthy growth.
Flower drop
Why it happens
Excessive heat or inconsistent watering can cause flowers to drop prematurely.
How to fix it
Maintain consistent moisture and provide some afternoon shade during peak heat.
Care through the year
Spring
In spring, prepare the soil by adding compost and ensure consistent watering as new growth emerges. Fertilize with a balanced fertilizer to promote healthy blooms.
Summer
During summer, monitor soil moisture closely, especially in hot weather. Provide some afternoon shade if temperatures exceed 85°F (29°C) to prevent stress.
Fall
In fall, after flowering, prune back spent blooms and foliage to encourage healthy growth for the next season. Consider dividing the plant if it has become overcrowded.
Winter
In winter, protect the plant from extreme cold by applying a layer of mulch around the base. Avoid watering during dormancy unless there are prolonged dry spells.
Toxicity & Safety
Delphinium elatum is toxic to pets and children. All parts of the plant contain alkaloids that can cause symptoms such as nausea, vomiting, and diarrhea if ingested. Keep out of reach of curious pets and children.
Good to know
Why are my Delphinium elatum leaves turning yellow?
Yellow leaves on Delphinium elatum can indicate over-watering or a nutrient deficiency. Check the soil moisture and adjust your watering schedule accordingly.
How often should I water my Candle Larkspur?
Water your Delphinium elatum once a week, ensuring the top inch of soil dries out between waterings. Increase frequency during hot weather.
What is the best soil for Delphinium elatum?
Delphinium elatum thrives in well-draining, loamy soil with a pH of 6.0 to 7.0. A mix of garden soil, compost, and perlite works well.
How can I propagate Delphinium elatum?
You can propagate Delphinium elatum through seeds or division. Sow seeds in spring or divide established plants in early spring or fall.
What should I do if my Delphinium elatum is wilting?
Wilting can be a sign of under-watering or root rot. Check the soil moisture and adjust your watering schedule, and inspect the roots if necessary.
When should I prune my Candle Larkspur?
Prune Delphinium elatum after flowering to encourage new growth and remove spent blooms. Use clean shears to cut stems just above a leaf node.
Is Delphinium elatum toxic to pets?
Yes, Delphinium elatum is toxic to pets and children. All parts of the plant contain alkaloids that can cause nausea and vomiting if ingested.
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