Species
Lathyrus odoratusSweet Pea15 other cultivars
‘Pulsar’Pulsar Sweet Pea
‘Cupani’Cupani Sweet Pea
‘Painted Lady’Painted Lady Sweet Pea
‘High Society’Sweet Pea 'High Society'
‘Nuance’Nuance Sweet Pea
‘Nimbus’Nimbus Sweet Pea
‘Sugar Magnolia’Sugar Magnolia Sweet Pea
‘Almost Black’Almost Black Sweet Pea
‘Enchante’Enchanted Sweet Pea
‘April in Paris’Sweet Pea 'April in Paris'
‘Blue Vein’Blue Veined Sweet Pea
‘Mrs Collier’Mrs. Collier Sweet Pea
‘Streamers Chocolate’Chocolate Streamers Sweet Pea
‘Wiltshire Ripple’Wiltshire Ripple Sweet Pea
‘Prince of Orange’Prince of Orange Sweet Pea
The Story
Plant Bio
Sweet Pea 'Black Knight' is known for its rich dark purple to almost black flowers. It is a climbing plant that can be supported by trellises or fences.
This cultivar is prized for its dark flower color, which stands out in gardens and is less commonly found among sweet peas.
Uses & Benefits:
Essentials
At a Glance
Plant Type
Annual
Height
72 inches
Width
12 inches
Light
Full Sun, Partial Sun
Zones
4, 5, 6, 7, 8, 9, 10
Water
Moderate
Humidity
Moderate
Lifespan
Annual
Native To
Mediterranean region
Toxicity
Toxic to pets if ingested
Bloom period
Mid-spring – Late spring
In flower about 2 months of the year
Planting
How to Grow
- Tuck seeds into moist soil in early spring for best germination.
- Mist cuttings regularly to maintain humidity and promote rooting.
- Provide trellises or supports for climbing growth during early growth stages.
- Water consistently to keep soil evenly moist but not waterlogged.
- Apply a balanced fertilizer monthly during the active growing season.
- Deadhead spent flowers to encourage prolonged blooming.
Pro Tip
Use well-draining, rich soil and provide full sun for vibrant blooms.
Keep It Thriving
Care Guide
Do
- Water regularly to keep soil moist 🌱
- Support climbing stems with trellises or stakes
- Deadhead flowers to promote continuous blooming
- Apply organic fertilizer monthly
Don't
- Avoid overwatering to prevent root rot ❌
- Do not disturb roots during flowering
- Prevent excessive shade which reduces flowering
- Avoid using harsh chemical pesticides
Seasonal Care Calendar
| Task | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Harvest | ||||||||||||
| Pinch | ||||||||||||
| Plant | ||||||||||||
| Stake |
Watch Out For
Pests & Diseases
Common Pests
Common Diseases
In the Garden
Landscape Uses & Companions
Landscape Uses
Companion Plants
Multiply
Propagation Methods
Good to Know
Common Questions
Sweet Pea 'Black Knight' questions
What zones can Sweet Pea 'Black Knight' grow in?
Sweet Pea 'Black Knight' is hardy in USDA Zones 4–10. Inside that range it survives winter in the ground; outside it, grow it as an annual or a container plant you protect.
Is Sweet Pea 'Black Knight' deer resistant?
Not reliably. Deer may browse Sweet Pea 'Black Knight', especially tender spring growth — plan on repellents or fencing where pressure is high.
When does Sweet Pea 'Black Knight' bloom?
Sweet Pea 'Black Knight' typically blooms in mid-spring through late spring. Exact timing shifts a week or two with your zone — Sow's bloom calendar maps it to your garden.
Does Sweet Pea 'Black Knight' need full sun?
Sweet Pea 'Black Knight' does best in full sun to part shade. In hot climates, afternoon shade keeps blooms fresher longer.
More Lathyrus to compare
Pulsar Sweet Pea
Lathyrus odoratus 'Pulsar'
Cupani Sweet Pea
Lathyrus odoratus 'Cupani'
Erewhon Sweet Pea
Lathyrus x belinensis 'Erewhon'
Sweet Pea
Lathyrus odoratus
Painted Lady Sweet Pea
Lathyrus odoratus 'Painted Lady'
Sweet Pea 'High Society'
Lathyrus odoratus 'High Society'
Keep exploring
Explore the genus
Grow Sweet Pea 'Black Knight' 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.