Origin
Penstemon spectabilis Thurb. ex Gray var. subviscosus (Keck) McMinn, also known as the large-flowered penstemon, is a perennial plant species that originated in California, United States.
Common Names
The plant is commonly known as the large-flowered penstemon and sticky penstemon due to its characteristic sticky surface.
Uses
The large-flowered penstemon is a popular ornamental plant due to its showy purple or blue flowers, which bloom in late spring through summer. It is often used in gardens and landscaping to attract pollinators such as bees and hummingbirds. In addition, some indigenous communities have traditionally used this plant for medicinal purposes, including treatment of respiratory illnesses such as coughs and colds.
General Appearance
The large-flowered penstemon typically grows to be 2 to 3 feet tall and 1 to 2 feet wide. It has distinct sticky leaves and stems that exude a strong aroma when crushed. The plant produces large, tubular flowers that range in color from deep purple to blue. The flowers grow in clusters on tall stems that rise above the foliage.
Light Requirements
Penstemon spectabilis var. subviscosus prefers full sun but it can also tolerate partial shade. When grown in partial shade, the stems of the plant may become elongated and the flowering may be reduced.
Temperature Requirements
This plant can grow in a wide range of temperatures. It prefers cool summers and mild winters. It can tolerate cold temperatures up to -10°C (14°F) and hot temperatures up to 35°C (95°F).
Soil Requirements
Penstemon spectabilis var. subviscosus prefers well-drained soil that is rich in organic matter. It can grow in a range of soil types, such as sandy loam, well-drained soils, and rocky soils. This plant can tolerate alkaline soil.
The pH of the soil should be between 6.0 and 7.5. The plant can tolerate moderate drought but it requires regular watering during the growing season. Overwatering can lead to root rot, so the soil should be allowed to dry out slightly before watering again.
Cultivation Methods
Penstemon spectabilis Thurb. ex Gray var. subviscosus (Keck) McMinn requires well-drained soil with a pH range of 6.0-7.5. The plant thrives in full sun but can also tolerate partial shade. It is recommended to plant seeds in the spring after any chance of frost has passed. The seeds should be planted to a depth of 1/8 inch and spaced about 12 inches apart.
Watering needs
The plant requires consistent watering during its initial growth stages. Once fully established, it becomes moderately drought-tolerant. Watering should be done once a week during the growing season, and the soil kept moist. However, ensure the roots do not trap excess water, as this can lead to root rot. During the winter, watering should be reduced due to the dormant stage of the plant.
Fertilization
The plant requires moderate fertilization. During its growing period, it is recommended to use a nitrogen-rich fertilizer once a month. Alternatively, organic fertilizers can be used, including compost, manure, or fish emulsion. One can also use slow-release fertilizers for the plant. Avoid over-fertilization as it can lead to excessive foliage growth at the expense of flowers.
Pruning
Penstemon spectabilis Thurb. ex Gray var. subviscosus (Keck) McMinn requires minimal pruning. However, to increase the number of flowers, it is recommended to cut back the stems by half in early spring before new growth appears. Deadheading should also be done regularly to prevent the plant from forming seeds and promote new growth and better flowering. Dead or diseased stems can also be pruned to maintain neatness and good health.
Propagation of Penstemon Spectabilis Thurb. ex Gray var. Subviscosus (Keck) McMinn
Penstemon spectabilis Thurb. ex Gray var. subviscosus (Keck) McMinn can be propagated by several methods. Here are some ways you can propagate this plant:
Seed Propagation
Penstemon spectabilis Thurb. ex Gray var. subviscosus (Keck) McMinn can be propagated by seed. You can collect seeds from the plant's capsules once they have fully matured. The seeds need to be cleaned and dried before sowing.
You can start the seeds indoors in early spring or direct sow them in the fall. The seeds require light to germinate, so do not cover them with soil. Keep the soil moist, and the temperature between 60-70°F for germination to occur.
Once the seedlings have grown their second set of true leaves, you can transplant them into individual pots and harden them off before planting them outdoors.
Division
Penstemon spectabilis Thurb. ex Gray var. subviscosus (Keck) McMinn can also be propagated by division. Dividing the plant will not harm the mother plant and can even help to rejuvenate it.
Divide the plant in early spring when new growth has started to emerge. Carefully dig up the plant and cut the root ball into several sections. Each section should have at least one stem and a good root system. Replant the divided sections in their new locations and water thoroughly.
Cuttings
Penstemon spectabilis Thurb. ex Gray var. subviscosus (Keck) McMinn can also be propagated by taking stem cuttings. Take cuttings in early summer when the plant is actively growing.
Take a 4-6 inch cutting from the tip of a non-flowering stem. Remove the lower leaves, leaving only a few at the top. Dip the cut end in rooting hormone and plant the stem in a well-draining potting mix. Keep the soil moist and the cutting in a partially shaded area. Rooting should occur within 4-6 weeks.
Once the cutting has developed roots, you can transplant it into a larger pot or directly into the garden.
Disease and Pest Management for Penstemon Spectabilis Thurb. ex Gray var. Subviscosus (Keck) McMinn
Penstemon spectabilis Thurb. ex Gray var. subviscosus (Keck) McMinn, commonly known as the showy penstemon, is a beautiful perennial plant that belongs to the family Plantaginaceae. The plant is native to North America and is highly valued for its stunning display of tubular, bell-shaped flowers that come in various bright colors.
However, like all plants, the showy penstemon is susceptible to a few pests and diseases which can significantly affect its growth and overall appearance. Here are some of the common disease and pest management practices for this plant:
Pest Management
Aphids: These tiny, soft-bodied insects can infest the showy penstemon, causing the plant to wilt and yellow. To manage aphids, you can spray the plant with a mixture of water and dish soap or insecticidal soap. Alternatively, you can introduce natural predators like ladybugs and lacewings to the garden.
Spider Mites: These pests are common in hot, dry conditions and can cause yellowing and wilting in the showy penstemon. To manage spider mites, you can spray the plant with a powerful jet of water or use insecticidal soap. Avoid using broad-spectrum insecticides as they can kill beneficial insects that help control spider mites.
Disease Management
Crown Rot: This disease is caused by a fungus that attacks the roots of the showy penstemon, causing them to rot and die. To manage crown rot, you can remove infected plants and replace the soil. Avoid planting the showy penstemon in poorly drained soils.
Powdery Mildew: This fungal disease appears as a white, powdery coating on the leaves and stems of the showy penstemon. To manage powdery mildew, you can remove infected plant parts and ensure proper air circulation in the garden. You can also use fungicidal sprays to control the disease.
Overall, by following these disease and pest management practices, you can help keep your showy penstemon healthy, vibrant, and beautiful.
