Overview:
Penstemon crandallii A. Nels. ssp. crandallii is a herbaceous perennial plant that belongs to the genus Penstemon in the family Plantaginaceae. This species is commonly known as Crandall's beardtongue, and it is native to the western United States.
Description:
Crandall's beardtongue plant has a clumping habit, and it grows to a height of around 60 to 90 cm. The leaves of this plant are narrow, lance-shaped, and have a grayish-green color. The inflorescences are typically composed of many tubular flowers that are arranged in loose, branching clusters at the ends of the stems. The flowers are generally pink to lavender in color, and they open from late spring to early summer.
Uses:
Crandall's beardtongue has both ornamental and medicinal uses. In landscaping, this plant is a popular choice for its attractive flowers that add color and interest to gardens. It also attracts pollinators such as bees, butterflies, and hummingbirds, which makes it an excellent choice for pollinator gardens. Medicinally, the leaves of the plant have been used by Native Americans to treat colds, headaches, and other ailments.
Cultivation:
Crandall's beardtongue is a relatively hardy plant that requires well-drained soil and full sun to thrive. It prefers dry to moist conditions and is relatively drought-tolerant once established. This plant is easy to propagate from cuttings or seed, and it can be grown in pots or directly in the ground. Regular pruning can help to promote a bushier habit and stimulate more flowering.
Light Requirements
Penstemon crandallii A. Nels. ssp. crandallii thrives in full sunlight. The plant requires at least 6 hours of direct sunlight per day for optimal growth. However, it can tolerate partial shade, but the flowering may be less profuse.
Temperature Requirements
The plant is native to the subalpine regions, which have cool temperatures. Therefore, it prefers moderate to cool temperatures ranging from 55 - 75°F (13 - 24°C). Temperatures exceeding 80°F (27°C) may cause heat stress and damage to the plant. During the winter season, it can tolerate temperatures as low as 10°F (-12°C) and the plant goes dormant.
Soil Requirements
The plant grows well in well-drained soils with a pH range of 6.5 - 7.5, preferably with a sandy or loamy texture. A nutrient-rich soil with organic matter is beneficial, but the plant can tolerate poor soils as long as the drainage is good. Waterlogging and poorly drained soils can cause root rot and damage the plant.
Cultivation:
The Penstemon crandallii A. Nels. ssp. crandallii is a herbaceous, perennial plant that grows naturally in rocky or gravelly soils, in mountainous areas. To cultivate it in your garden, it is best to mimic its natural habitat by providing a well-draining, sandy or rocky soil mixture with a slightly alkaline pH, in a sunny location. This plant is hardy in USDA zones 4 to 8, so make sure the location you choose provides the required cold hardiness.
Watering Needs:
Penstemon crandallii A. Nels. ssp. crandallii prefers moderate watering, not too much and not too little. This means you should water it regularly, about once per week, or when the top 1-2 inches of soil feel dry to the touch. Avoid overwatering, which can cause root rot, or underwatering, which can lead to dehydration and stress. During the winter season, reduce watering to reflect the dormancy period.
Fertilization:
Penstemon crandallii A. Nels. ssp. crandallii does not require frequent fertilization, but it benefits from a yearly application of a balanced, slow-release fertilizer in the spring. This will provide essential macronutrients and micronutrients, enhancing the plant's growth and blooming potential. Avoid overfertilizing, which can lead to excessive foliage growth and reduced flower production.
Pruning:
Penstemon crandallii A. Nels. ssp. crandallii benefits from annual pruning, which will improve its shape, remove diseased or damaged foliage, and stimulate the plant's growth and flowering potential. Prune back the entire plant to about 6-8 inches in the late winter or early spring, before the new growth appears. Additionally, deadhead the flowers regularly, which will encourage the plant to produce new blooms throughout the growing season.
Propagation of Penstemon crandallii A. Nels. ssp. crandallii
Penstemon crandallii A. Nels. ssp. crandallii, commonly known as Crandall's beardtongue, can be propagated via several methods including seeds, cuttings, and division.
Propagation by seeds
The most common method of propagation for Penstemon crandallii is by seeds. Seeds can be sown outdoors in the fall or indoors in the spring. To increase the germination rate, seeds can be soaked in water for a few hours before planting. They require well-draining soil and consistent moisture until they germinate. Seeds should be kept moist but not waterlogged and should be kept in a warm location. Germination can occur over several weeks.
Propagation by cuttings
Propagation by cuttings is another method used for Penstemon crandallii. Softwood cuttings taken in the early summer can be rooted in a moist well-draining soil mix. Cuttings should be about 4-6 inches long and taken from the non-flowering stem. The cuttings should be dipped in rooting hormone and placed in the soil mix. Bottom heat can be used to expedite the rooting process. Keep the soil mix moist but not waterlogged.
Propagation by division
Penstemon crandallii can also be propagated by division. This method involves dividing the plant into several smaller sections, each with its own root system. The best time to divide the plant is in the early spring before active growth begins. Dig up the entire clump and separate it into smaller sections with a clean sharp knife. Each section should have its own stem and root system. Replant the sections in a well-draining soil mix and water thoroughly.
Disease and Pest Management for Penstemon crandallii A. Nels. ssp. crandallii
Penstemon crandallii A. Nels. ssp. crandallii is a beautiful plant that's native to western North America. While it's relatively disease-resistant, it can still fall prey to certain diseases and pests that can cause damage to the plant. Here's what you need to know about disease and pest management for Penstemon crandallii:
Common Diseases
Some of the most common diseases that can impact Penstemon crandallii include:
- Root Rot: This disease is caused by a soil-borne fungus and can cause the roots to rot, leading to stunted growth, yellowing leaves, and wilting. To prevent root rot, make sure to plant Penstemon crandallii in well-draining soil.
- Powdery Mildew: Powdery mildew can cause a white, powdery coating to form on the leaves and stems of the plant, inhibiting its growth. To manage powdery mildew, remove any infected parts of the plant, and spray with a fungicide. Make sure to keep the plant well-ventilated to prevent the spread of the disease.
- Bacterial Blight: Bacterial blight can cause brown spots to form on the leaves and stems of the plant, leading to wilting and leaf drop. To manage bacterial blight, remove any infected parts of the plant and apply a copper-based fungicide.
Common Pests
Some of the most common pests that can impact Penstemon crandallii include:
- Aphids: Aphids are small insects that can suck the sap out of the plant, causing the leaves to yellow and curl. To manage aphids, spray the plant with a strong stream of water, release ladybugs in the garden, or apply an insecticidal soap.
- Spider Mites: Spider mites are tiny pests that can spin webs and cause the leaves to appear stippled. They're often found in dry, hot weather. To manage spider mites, spray the plant with a strong stream of water, apply neem oil, or release predatory mites in the garden.
- Thrips: Thrips can cause the leaves to silver and distorted, and they can also spread viral diseases. To manage thrips, remove any infected parts of the plant, and apply an insecticide containing spirotetramat or spinosad.
By being vigilant and taking proper care of your Penstemon crandallii, you can prevent and manage any potential diseases and pests.
