Introduction to Black Cardinal
The black cardinal (Lobelia cardinalis) is a popular ornamental plant grown for its beautiful fiery red flowers. This striking plant is a herbaceous perennial native to North America and belongs to the bellflower family. With proper care, black cardinal can thrive for many years and provide gorgeous color in shady garden spots.
Bold red flowers emerge in late summer on spikes up to 3 feet tall. The lobed leaves are light green and provide an attractive backdrop to the blooms. Black cardinal has an upright habit and naturally forms clumps, so it is best planted in groups for maximum impact. Provide shade and consistent moisture for the best performance. Though relatively low-maintenance, fertilizing during the active growing season will promote vigorous growth and maximum flowering.
propagate new plants by seed, stem cuttings, or division. Black cardinal drops seed, so once established in the garden, it often self-seeds and spreads gently over time. New seedlings are easily transplanted to other parts of the garden. Stem cuttings or plant division are more reliable methods of propagation and will produce mature, flowering plants more quickly.
Choosing the Perfect Location
Black cardinal thrives in shady spots with moist, humus-rich soil. It performs best in areas with partial shade and shelter from strong winds. Some dappled sunlight is fine, but avoid full sun exposure, especially in hot climates. The soil should remain consistently moist but not soggy. Sandy, well-drained loam amended with compost or peat moss is ideal.
Suitable locations in the garden include:
- Under deciduous trees where it will receive shade in summer but sun in fall after leaves drop.
- Alongside a building or fence where buildings provide shelter and shade for part of the day.
- In a woodland garden with other shade-loving plants like hostas, astilbes and heucheras.
- At the edge of a pond or stream where the soil remains moist.
Black cardinal can tolerate short periods of drought once established but will suffer in very dry conditions. New plantings especially require frequent and consistent watering for the first few months. Never let the soil completely dry out.
|Partial shade||Medium to moist||Zones 3-8|
Fertilizer requirements are moderate. Apply a balanced granular fertilizer once a month during the active growing season. Slow-release fertilizers can also be used. [Reduce] (https://www.gardeningknowhow.com/ornamental/flowers/cardinal-flower/how-to-fertilize-cardinal-flowers.htm) or discontinue feeding in fall to allow the plant to prepare for winter. Excess fertilizer late in the season may stimulate new tender growth that will not harden off properly before frost.
For maximum impact, plant black cardinal in groups of 3 or more spaced about 18 to 24 inches apart. The dense clumps of upright scarlet flowers make an eye-catching display in late summer. Mulch around the base of the plants to help retain moisture in the soil and prevent weed growth.
Watering and Fertilizing Tips
Black cardinal requires consistent moisture for healthy growth and flowering. The soil should never be allowed to completely dry out, especially for newly planted specimens. Water regularly, providing about 1-2 inches per week. Check the top few inches of soil before watering to determine if it feels dry. During hot and dry weather, watering 2-3 times a week may be necessary.
Reduce watering frequency in fall as the weather cools to allow the plant to prepare for dormancy. However, do not allow the soil to dry out completely even after frost. Evergreens and plants that remain partially green through winter still require occasional watering when the top few inches of soil are dry.
Fertilize black cardinal during the active growing season. Balanced, all-purpose fertilizers such as 10-10-10 work well for most garden plants. Apply at 1/2 the recommended strength once a month from late spring through summer. Slow-release fertilizers can also be used and only need to be applied once early in the season. Reduce or discontinue feeding in fall.
|Spring||Medium||Begin light feeding|
|Fall||Medium to low||Reduce or stop feeding|
|Winter||Low||Do not feed|
Never fertilize after September to prevent new growth that will not harden off properly before frost. Excess fertilizer can also lead to disease issues. Follow the directions on the product packaging for how much and how often to feed based on your local climate and rain levels.
New plantings especially require close attention to watering and feeding needs for the first few months. Water deeply but regularly, especially for the first few weeks. Start a regular fertilizing program once new growth appears in spring. After the first growing season, well-established plantings can typically thrive with moderate fertilizing and slightly less frequent watering. However, as a general rule, never let the soil completely dry out for black cardinal.
Consistently moist soil and regular feeding will produce the best growth and flowering for this striking perennial. Pay close attention to the needs of your plants and adjust as necessary based on rainfall and temperature in your local area. Healthy, well-established specimens may require little intervention, but monitoring soil conditions regularly is the key to success.
Pruning and Propagation Techniques
Black cardinal requires little pruning to maintain its shape and size. Only remove dead or damaged foliage in early spring before new growth starts. Pruning just after flowering will also promote new shoot growth and flowering for the next season. However, pruning in fall should be avoided as cutting plants back at this time may reduce spring blooms.
To propagate black cardinal, collect fresh seed as soon as the seed capsules start to split in late summer. Sow the tiny seeds indoors a few weeks before the last spring frost for germination. Cover the seeds very lightly with seed starting mix and keep the soil moderately moist and warm (around 70 F). Seed will germinate in 2-4 weeks under ideal conditions. Transplant seedlings into the garden after the last frost when they have 3-4 true leaves.
Stem cuttings can also be taken in early to midsummer. Choose actively growing stems with foliage and remove up to 6 inches from the tips. Remove bottom leaves and dip the base in rooting hormone (optional). Insert into well-draining rooting mix and cover with plastic to retain humidity. Place in a location out of direct sun. Roots should form in 2-3 weeks. Once rooted, harden the cuttings off and move to a shady outdoor spot before transferring to a permanent location in the garden.
|Seed||Late summer, sow in spring||Low-Medium|
In fall, mature clumps of black cardinal can be divided to produce new plants. Dig up the entire clump and separate it into smaller divisions, each with both foliage and roots. Replant the divisions promptly at the same depth in amended, well-drained soil. Division is the most reliable way to propagate new plants and will produce mature, flowering specimens more quickly. However, plants may produce fewer blooms the season following division.
Once propagated and established in the garden, new seedlings, cuttings and divisions should receive the same care as mature plants. Provide partial shade, consistently moist soil and regular feeding during the growing season for the best performance. With the proper conditions, new plants will produce flowers within 1-2 years, though flowering may be sparse the first season after propagation. Healthy, well-established clumps may produce 50 or more flower spikes!
[ Black cardinal] (https://en.wikipedia.org/wiki/Lobelia_cardinalis) is easily propagated and rewarding to grow. With simple techniques, you can increase your stock of this striking plant and create lush plantings to enjoy for years to come. By starting with high quality seed or cuttings and providing ideal conditions, you’ll have the most success in producing mature, flowering plants.