The black night cultivar of the Delphinium spp. is a tall herbaceous perennial native to North America. Delphiniums are certainly eye-catching additions to any landscape with their tightly packed spikes, maple-like leaves, and uniquely-shaped flowers.
But, the black knight cultivar adds to the plant's impressive display with its semi-double, deep purple flowers that bloom in the summer and fall. Black knight delphiniums have a moderate to fast growth rate in the spring but generally aren't long-lived plants.
Rocket larkspur has good resistance to disease and is generally not prone to illnesses. However, it can be vulnerable to pests and diseases present in its surroundings. These outbreaks are usually mild. Care-wise, this plant requires moderate maintenance. It should be pruned regularly to maintain an attractive appearance and healthy growth. Fertilizing can also help encourage flowering. Rocket larkspur is appropriate for anyone with outdoor space, such as a garden or patio, and does not need much gardening experience. It may demand more attention when grown indoors.
How to keep Delphinium Nanum.
Light
Rocket larkspur flourishes in locations that have unobstructed access to sunlight throughout the day and can endure areas where the sunlight is somewhat moderated. Insufficient sun exposure can potentially inhibit its development, whereas excessive amounts don't notably cause any harm.
Water
Water your black knight delphiniums 1 to 2 times per week with about an inch of water to maintain moist soil. You might need to increase the frequency of water in times of hot weather or less rainfall. However, if the top inch of soil feels moist, then you can withhold watering for another day or so.
Temperature
The Rocket larkspur is native to environments where the typical temperatures vary between 68 and 95 °F (20 to 35 ℃). It thrives in warm weather, but can withstand some degree of change. Adjustments to seasonal temperatures may be required for its best possible growth.
Fertilizer
When the Rocket larkspur has most of its flowers fully bloomed, it indicates the appropriate moment to recommence fertilization. Start the fertilizing procedure once every three to four weeks, provided the weather conditions are suitable, when the flowers are flourishing the most. However, when the Rocket larkspur begins to generate fewer new flowers, cease fertilizing as there's no requirement for additional nutrients when the plant is not capable of producing more flowers.
Pruning
During its growing season, your delphinium will benefit from some trimming. Thin back flower stalks once they reach about 3 inches tall to ensure strong growth. When blooming occurs, deadhead the primary flower stalks and leave the smaller side flowers. After blooming, you can cut the stalks to ground level to encourage a second round of blooms late in the season.
Pot & Repot
During the repotting process of Rocket larkspur, choose a container that's 1-2 inches (2.5-5 cm) wider in diameter, with a focus on excellent drainage. Opt for a potting blend that provides good drainage and think about adding perlite for additional drainage capacity. Perform the repotting in spring or at the start of summer, drench completely with water, and then place it in a location with less sunlight initially.
Toxicity
Black knight delphiniums contain a poisonous substance that may cause skin irritation and severe digestive problems. Wear protective gear when handling these plants and keep them away from children and pets.
Further reading →
The toxicity and danger assessments provided are for reference only. We do not assure their accuracy, so it's crucial not to depend on them. Seek professional advice when necessary for accurate guidance.
Botanical profile.
- Plant Type
- Herb
- Life Cycle
- Annual, Perennial, Biennial
- Genus
- Delphinium
- Family
- Ranunculaceae
- Hardiness Zone
- 6-9
- Mature Height
- 0.61 m to 1.22 m
- Mature Spread
- 30 cm to 61 cm
- Leaf Color
- Green
- Leaf Type
- Deciduous
- Flower Color
- Blue, Purple, Pink, White
- Flower Size
- 5.08 cm
- Bloom Time
- Late spring, Early summer, Mid summer
- Planting Time
- Spring
- Harvest Time
- Mid summer
- Native Area
- Northern hemisphere
