Origin and Common Names
Rudbeckia laciniata L. ssp. ampla (A. Nels.) W.A. Weber is a species of flowering plant in the Asteraceae family. It is native to North America and can be found growing wild in moist meadows, prairies, and along streambanks from Ontario to Georgia and west to Colorado. The plant is also commonly known as Cutleaf Coneflower, Green-headed Coneflower, or Tall Coneflower.General Appearance
Rudbeckia laciniata L. ssp. ampla is a tall, herbaceous perennial that can grow up to 10 feet in height. The plant has large, deeply-lobed leaves that give it a fern-like appearance. The leaves are dark green and can be between 6 and 12 inches long. The plant produces bright yellow, daisy-like flowers that are about 3 inches in diameter. The flowers have yellow or greenish-yellow centers and numerous petal-like ray flowers that droop downward. The plant blooms from midsummer to early fall and the seeds are produced in large, flattened seed heads.Uses
Rudbeckia laciniata L. ssp. ampla has several uses, both medicinal and ornamental. The plant has been used by Native Americans to treat various ailments, including colds, flu, and snake bites. The Cherokee also used the root to make a tea to induce sweating and to relieve pain. In modern times, the plant is often used in ornamental gardens and landscaping due to its tall height and attractive flowers. It is also a popular plant for attracting pollinators such as bees and butterflies. However, it is important to note that the plant can be toxic to livestock if ingested in large quantities.Light Conditions
Rudbeckia laciniata ssp. ampla thrives well in full to partial sun. It requires a minimum of 4-6 hours of sunlight to grow optimally. The plant can tolerate direct sunlight, but it would need partial shade during afternoon to prevent water loss due to excessive evaporation. The plant can grow in shady regions but may not bloom as much as when in full sun.
Temperature Requirements
Rudbeckia laciniata ssp. ampla thrives in various temperature zones. The plant is hardy in USDA hardiness zones 4-9, and it can tolerate temperatures ranging from -34°C (-30°F) to 40°C (104°F). It prefers cooler temperatures between 16 to 21°C (60 to 70°F) for optimal growth, but it can still grow in higher temperatures if well hydrated.
Soil Requirements
Rudbeckia laciniata ssp. ampla requires well-draining soils that are rich in organic matter. The plant can grow in various soil textures, but it prefers sandy loam or loamy soil. The pH of the soil for Rudbeckia laciniata ssp. ampla should be slightly acidic to neutral between 5.5 to 7.5. The plant can also tolerate mildly alkaline soil if necessary.
Cultivation methods
Rudbeckia laciniata L. ssp. ampla (A. Nels.) W.A. Weber, commonly known as the cutleaf coneflower, prefers to grow in full sun to partial shade in well-draining soil. This plant can adapt to various soil types but thrives in fertile and moist soil. It is ideal to plant the seeds or seedlings in early spring or late fall in regions with mild winters.
Watering needs
This plant requires moderate watering, especially during hot and dry spells, to keep the soil moist. Watering should be done once a week, and the frequency may increase during the hot summer months. However, it is crucial not to overwater the cutleaf coneflower as standing water can encourage root rot.
Fertilization
The cutleaf coneflower does not need a lot of fertilization but can benefit from an all-purpose fertilizer with balanced nitrogen, phosphorus, and potassium levels. Apply the fertilizer during the growing season, preferably once a month, to enhance the plant's growth and flowering potential.
Pruning
Pruning the cutleaf coneflower is not necessary, but it can help to manage its size and shape. The plant usually grows tall, up to 9 feet, and can require staking to prevent it from falling over. Deadheading spent flowers can prolong the blooming season and improve the overall appearance of the plant. Cut the stems down to the ground during the fall or winter to encourage new growth in the spring.
Propagation of Rudbeckia laciniata L. ssp. ampla (A. Nels.) W.A. Weber
Rudbeckia laciniata L. ssp. ampla (A. Nels.) W.A. Weber, commonly known as cutleaf coneflower, is a perennial plant that belongs to the Asteraceae family. The plant can grow up to 6 feet tall, producing large yellow flowers with a greenish center that bloom in midsummer to early fall. The plant's propagation is relatively easy, and there are a few methods through which this plant can be propagated.
Propagation through Seeds
The most common propagation method for Rudbeckia laciniata L. ssp. ampla is through seeds. The coneflower produces large quantities of seeds in late summer and early fall, and these can be harvested for propagation. The best time to harvest the seeds is when the seed heads have turned brown and dry. Collect the seed heads and store them in a dry place until ready for propagation.
To propagate through seeds, plant them in a seed-starting tray or individual pots filled with well-draining soil. Ensure that the seeds are not covered with too much soil, as this can inhibit germination. The seeds require light to germinate, so provide them with ample light and keep the soil moist. The seeds will germinate in 7-14 days.
Propagation through Division
Rudbeckia laciniata L. ssp. ampla can also be propagated through division. This method is best done in early spring before new growth appears. Dig up the entire clump and gently separate the sections, ensuring that each section has sufficient roots. Replant the divided sections in a well-draining soil mix and water thoroughly.
Propagation through Cuttings
Propagation through cuttings is another method that can be used for Rudbeckia laciniata L. ssp. ampla. Take stem cuttings in early summer before any flower buds have formed. Cut 6-inch sections of the stem and remove the lower leaves. Dip the cut end of the stem in rooting hormone and plant in a soil mix of half potting soil and half perlite. Keep the soil moist and the cutting in bright, indirect light until roots have formed.
Propagation of Rudbeckia laciniata L. ssp. ampla is relatively easy, and with any of these methods, one can easily propagate and grow new plants.
Disease Management
Rudbeckia laciniata L. ssp. ampla, commonly known as cutleaf coneflower, is a hardy plant that is known to be relatively resistant to diseases. However, there are several fungal diseases that can infect the plant, including black spot, powdery mildew, and rust.
Black spot is a fungal disease that thrives in warm, humid weather and can cause dark spots on the leaves of the plant. To manage black spot, it is recommended to remove any infected leaves and stems as soon as they are noticed and destroy them to prevent the spread of the disease. Additionally, providing adequate spacing between plants and ensuring good air circulation can help reduce the risk of infection.
Powdery mildew is another fungal disease that can infect Rudbeckia laciniata L. ssp. ampla. It appears as a white powdery coating on the leaves and stems of the plant and can weaken the plant if left untreated. To manage powdery mildew, it is recommended to remove and destroy any infected leaves and to avoid overhead watering. Additionally, applying fungicides can help control the spread of the disease.
Rust is a fungal disease that appears as small, reddish-brown spots on the leaves of the plant. If left untreated, it can spread and cause premature leaf drop. To manage rust, it is recommended to remove and destroy any infected leaves and to avoid watering the plant from above. Applying fungicides can also help control the spread of the disease.
Pest Management
Although Rudbeckia laciniata L. ssp. ampla is relatively resistant to pests, there are a few insects that can pose a threat to the plant.
One of the most common pests that affect Rudbeckia laciniata L. ssp. ampla is the aphid. Aphids are small, soft-bodied insects that feed on the sap of the plant, causing stunted growth and yellowing leaves. To manage aphids, it is recommended to use insecticidal soap or neem oil and to encourage natural predators, such as ladybugs, to help control the population.
The Japanese beetle is another pest that can cause damage to Rudbeckia laciniata L. ssp. ampla. These beetles feed on the leaves and flowers of the plant, causing skeletonization of the leaves and reduced flower production. To manage Japanese beetles, it is recommended to handpick them off the plant and to use insecticides if necessary.
Finally, spider mites can also be a problem for Rudbeckia laciniata L. ssp. ampla. These tiny pests feed on the plant's sap and can cause yellowing leaves and premature leaf drop. To manage spider mites, it is recommended to spray the plant with water to wash them off and to use insecticidal soap or neem oil to control the population.
