Guardian White
Delphinium elatum
Photo: Ermell · Wikimedia Commons · (CC BY-SA 4.0)
Uniform flowering time and plant height allows for efficient harvesting. The Guardian series is bred to perform well under short days for greenhouse production. Guardian also performs well in our field trials, blooming under long days. Vigorous plants with excellent bloom and stem quality for cut flowers. Also suitable for garden beds and landscaping. Compared to Magic Fountains Pure White, bloom color has a touch more ivory and green as the buds open. Attracts bees and butterflies. This species of delphinium is also known as candle larkspur. Perennial in Zones 3-7.
Harvest
105-125d
Days to harvest
Sun
Full sun
Zones
3–7
USDA hardiness
Height
3-5 feet
Planting Timeline
Showing dates for Guardian White in USDA Zone 7
All Zone 7 flower →Zone Map
Click a state to update dates
Guardian White · Zones 3–7
Growing Details
Zone-by-Zone Planting Calendar
| Zone | Indoor Start | Transplant | Direct Sow | Harvest |
|---|---|---|---|---|
| Zone 1 | May – June | July – August | July – September | — |
| Zone 2 | April – May | June – July | June – August | — |
| Zone 11 | January – January | January – February | January – March | — |
| Zone 12 | January – January | January – February | January – March | — |
| Zone 13 | January – January | January – February | January – March | — |
| Zone 3 | April – May | June – July | June – August | — |
| Zone 4 | March – April | June – June | June – July | — |
| Zone 5 | March – April | May – June | May – July | — |
| Zone 6 | March – April | May – June | May – July | — |
| Zone 7 | February – March | April – May | April – June | — |
| Zone 8 | February – March | April – May | April – June | — |
| Zone 9 | January – February | March – April | March – May | — |
| Zone 10 | January – January | February – March | February – April | — |
Complete Growing Guide
Uniform flowering time and plant height allows for efficient harvesting. The Guardian series is bred to perform well under short days for greenhouse production. Guardian also performs well in our field trials, blooming under long days. Vigorous plants with excellent bloom and stem quality for cut flowers. Also suitable for garden beds and landscaping. Compared to Magic Fountains Pure White, bloom color has a touch more ivory and green as the buds open. Attracts bees and butterflies. This species of delphinium is also known as candle larkspur. Perennial in Zones 3-7. According to Johnny's Selected Seeds, Guardian White is 105 - 125 days to maturity, perennial, hybrid (f1). Notable features: Use for Cut Flowers and Bouquets, Attracts Beneficial Insects.
Light: Full sun (6 or more hours of direct sunlight a day). Soil: High Organic Matter. Soil pH: Alkaline (>8.0). Drainage: Good Drainage. Height: 3 ft. 0 in. - 5 ft. 0 in.. Spread: 2 ft. 0 in. - 3 ft. 0 in.. Spacing: 12 inches-3 feet, 3 feet-6 feet. Growth rate: Medium. Maintenance: Medium. Propagation: Seed. Regions: Mountains, Piedmont.
Harvesting
Guardian White reaches harvest at 105 - 125 days from sowing per Johnny's Selected Seeds.
Edibility: Toxic if eaten.
Storage & Preservation
Store fresh Guardian White delphiniums in a cool location with high humidity. Keep cut stems in a vase with fresh, cool water (65-72°F) away from direct sunlight and ripening fruits. Shelf life is 7-10 days with proper care. Preservation methods include: (1) Air drying by hanging upside-down bundles in a dark, well-ventilated space for 2-3 weeks; (2) Pressing between newspaper under weight for 4-6 weeks to preserve flowers for crafts; (3) Silica gel drying for 3-5 days to maintain color and form for arrangements.
History & Origin
Guardian White is an F1 hybrid developed through controlled cross-pollination. Listed in the Johnny's Selected Seeds catalog.
Origin: Europe to Mongolia
Advantages
- +Uniform flowering and height streamlines efficient harvesting and processing
- +Performs excellently under both short and long day conditions
- +Vigorous growth with superior bloom and stem quality for cutting
- +Attracts pollinators while suitable for gardens and landscape applications
- +Perennial viability across cold climate zones three through seven
Considerations
- -Ivory-green bud coloration differs from pure white Magic Fountains variety
- -Requires staking or support due to tall candle larkspur growth habit
- -Susceptible to powdery mildew in humid greenhouse production environments
Companion Plants
Marigolds and Sweet Alyssum are the most useful neighbors here. French marigolds (Tagetes patula) deter aphids — which cluster readily on delphinium stems — through scent compounds that interfere with how aphids locate host plants. Sweet Alyssum draws in parasitic wasps and hoverflies that go after those same aphids once they've arrived. Lavender and Catnip work on a similar principle: both contain volatile oils that mask nearby plants from pest insects, and both thrive in the same full-sun, well-drained conditions Guardian White needs. Nasturtiums are worth planting a foot or two away as a trap crop — aphids will take them over the delphiniums given the choice, which makes monitoring and control a lot easier.
Black Walnut, Eucalyptus, and Fennel are the three to keep out. Black Walnut produces juglone through its root system — a compound that interferes with cellular respiration in sensitive plants, and delphiniums fall squarely in that category. The damage shows up as slow decline rather than any dramatic symptom, which makes it easy to misread. Eucalyptus causes similar problems through allelopathic compounds in its leaf litter and root exudates. Fennel suppresses most plants within a foot or two regardless of species and has no real place in a mixed flower bed.
Plant Together
Marigolds
Repel aphids, whiteflies, and nematodes while attracting beneficial insects
Lavender
Deters pests with strong fragrance and attracts pollinators
Sweet Alyssum
Attracts beneficial insects like lacewings and parasitic wasps
Nasturtiums
Act as trap crops for aphids and cucumber beetles
Petunias
Repel aphids, tomato hornworms, and other garden pests
Zinnia
Attracts beneficial predatory insects and butterflies
Cosmos
Attracts beneficial insects and provides natural pest control
Catnip
Repels mosquitoes, ants, and aphids more effectively than DEET
Keep Apart
Black Walnut
Produces juglone toxin that inhibits growth and can kill sensitive plants
Eucalyptus
Releases allelopathic compounds that suppress nearby plant growth
Fennel
Inhibits growth of most garden plants through allelopathic root secretions
Troubleshooting Guardian White
What you'll see, why it happens, and what to do about it.
Powdery white coating on leaves and stems, usually appearing mid-summer
Likely Causes
- Powdery mildew (Erysiphe aquilegiae or related species) — favored by warm days, cool nights, and poor airflow
- Crowded planting at less than 18-inch spacing trapping humidity around foliage
What to Do
- 1.Cut affected stems back to healthy growth and dispose of them in the trash, not the compost pile
- 2.Apply a diluted neem oil spray (2 tsp per quart of water) every 7 days until the outbreak clears
- 3.Space plants at the full 24 inches next season and avoid overhead watering in the evening
Wilting stems that snap easily at the base, with dark brown or black discoloration at the crown
Likely Causes
- Crown rot (Sclerotinia sclerotiorum or Botrytis cinerea) — both thrive in waterlogged soil around the crown
- Mulch piled directly against the stem holding moisture against the tissue
What to Do
- 1.Dig out and discard affected plants entirely — do not compost them
- 2.Pull mulch back 2–3 inches from the base of each plant to let the crown breathe
- 3.Improve drainage in the bed before replanting; delphiniums will not tolerate standing water for more than a few hours
Ragged holes in young leaves and flower buds, worst in cool, wet springs
Likely Causes
- Slugs (Arion or Deroceras species) — they feed at night and hide under debris during the day
- Earwigs (Forficula auricularia), which cause similar damage and are often misidentified
What to Do
- 1.Set out iron phosphate bait (Sluggo or equivalent) around the base of plants — it's safe around pets and won't harm beneficial insects
- 2.Clear any leaf litter or flat stones near the bed that slugs use as daytime shelter
- 3.Check for earwigs by flashlight an hour after dark; hand-pick into soapy water if populations are high
Tall flower spikes toppling or snapping at mid-stem after rain or wind, even without visible disease
Likely Causes
- Insufficient staking — Guardian White reaches 3–5 feet and the flower spike is heavy when fully loaded
- Over-fertilization with nitrogen producing fast, soft stem growth that can't support its own weight
What to Do
- 1.Install bamboo stakes at least 4 feet tall at transplant time, before stems need them — retrofitting stakes around mature growth damages roots
- 2.Tie loosely with soft garden twine in a figure-eight loop every 12 inches up the stem
- 3.Back off high-nitrogen fertilizers once the plant is established; a balanced 10-10-10 at half-rate in spring is enough
Frequently Asked Questions
How long do Guardian White delphiniums last in a vase?▼
Can Guardian White delphiniums be grown in containers?▼
Is Guardian White a good choice for beginner gardeners?▼
When should I plant Guardian White delphinium seeds?▼
How tall do Guardian White delphiniums grow?▼
What makes Guardian White different from Magic Fountains Pure White?▼
Growing Guides from Wind River Greens
Where to Buy Seeds
Sources & References
External authority sources used in compiling this guide.
- BreederJohnny's Selected Seeds
See the Methodology page for how this data is sourced, what's AI-assisted, and known limitations.