The Story
Plant Bio
Sanguisorba officinalis, known as Great Burnet, is a perennial herb with upright, clump-forming growth, featuring finely divided, dark green foliage and dense spikes of deep red to almost black flowers that attract pollinators.
The 'Blackthorn' cultivar is distinguished by its striking nearly black flower spikes, providing a dramatic contrast in ornamental plantings and enhancing dark-themed garden schemes.
Uses & Benefits:
Essentials
At a Glance
Plant Type
Perennial
Height
36 inches
Width
18 inches
Light
Full Sun, Partial Sun
Zones
4, 5, 6, 7, 8
Water
Prefers consistently moist soil
Humidity
Prefers moderate humidity
Lifespan
Perennial
Native To
Europe and Asia
Toxicity
Non-toxic to humans and pets
Bloom period
Mid-summer – Late summer
In flower about 2 months of the year
Marketplace
Where to Buy
Shipping costs Year-round shipping Free shipping
Planting
How to Grow
- Tuck seeds into moist soil in early spring
- Keep soil consistently moist during germination
- Transplant seedlings to a sunny spot after 6 weeks
- Water regularly until established
- Apply a layer of mulch to retain moisture
- Divide clumps every 3 years for vigorous growth
Pro Tip
Plant in well-drained soil with good air circulation for best results
Keep It Thriving
Care Guide
Do
- Water during dry periods 🌱
- Prune after flowering to maintain shape
- Mulch to conserve moisture
- Divide every 3 years for rejuvenation
Don't
- Avoid overwatering in winter ❌
- Don’t plant in waterlogged soil
- Refrain from heavy fertilizing during dormancy
- Don’t prune in late fall
Seasonal Care Calendar
| Task | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Deadhead | ||||||||||||
| Divide | ||||||||||||
| Fertilize | ||||||||||||
| Harvest | ||||||||||||
| Plant | ||||||||||||
| Spring Cleanup |
Watch Out For
Pests & Diseases
Common Pests
Common Diseases
In the Garden
Landscape Uses & Companions
Landscape Uses
Multiply
Propagation Methods
Good to Know
Common Questions
Great Burnet 'Blackthorn' questions
What zones can Great Burnet 'Blackthorn' grow in?
Great Burnet 'Blackthorn' is hardy in USDA Zones 4–8. Inside that range it survives winter in the ground; outside it, grow it as an annual or a container plant you protect.
Is Great Burnet 'Blackthorn' deer resistant?
Yes — Great Burnet 'Blackthorn' is rated deer-resistant. Deer typically pass it over, though extreme hunger can override any plant's defenses.
When does Great Burnet 'Blackthorn' bloom?
Great Burnet 'Blackthorn' typically blooms in mid-summer through late summer. Exact timing shifts a week or two with your zone — Sow's bloom calendar maps it to your garden.
Does Great Burnet 'Blackthorn' need full sun?
Great Burnet 'Blackthorn' does best in full sun to part shade. In hot climates, afternoon shade keeps blooms fresher longer.
More Sanguisorba to compare
Pink Tanna Sanguisorba
Sanguisorba officinalis 'Pink Tanna'
Japanese Burnet
Sanguisorba obtusa
Little Angel Great Burnet
Sanguisorba officinalis 'Little Angel'
Great Burnet
Sanguisorba officinalis
Tanna Great Burnet
Sanguisorba officinalis 'Tanna'
Thin-Leafed Burnet
Sanguisorba tenuifolia
Keep exploring
Explore the genus
Hardy in your zone?
Grow Great Burnet 'Blackthorn' with confidence
See it in a design of your actual yard, get zone-matched care reminders, and track it season by season in your garden journal.