Plant Description:
Penstemon watsonii Gray ssp. laxus (A. Nels.) Keck, commonly known as Watson's beardtongue, is a perennial herb that belongs to the family Plantaginaceae. It has a clumping growth habit and grows up to 1.5 feet tall. The plant has numerous basal leaves and stem leaves that are narrow and lance-shaped. The leaves are hairy with fine short hairs and their edges are slightly serrated. The flowers of Watson's beardtongue are tubular and range in color from lavender to purple to pink. Each flower has five spreading lobes at the end of a long tube that is about 1 inch long. The plant blooms in late spring to early summer and has long-lasting flowers that attract hummingbirds and bees.
Plant Origin and Distribution:
Penstemon watsonii Gray ssp. laxus (A. Nels.) Keck is native to the western United States and can be found in several states including Arizona, California, Colorado, Nevada, New Mexico, Oregon, Utah, and Wyoming. It grows naturally in mountains, rocky slopes, and dry ridges at elevations ranging from 1,500 to 9,000 feet above sea level. Watson's beardtongue is well adapted to the arid and semi-arid environments of the western United States and can also be found in disturbed areas, including roadsides and abandoned fields.
Plant Uses:
Watson's beardtongue has several uses both for ornamental and medicinal purposes. When planted in a garden, the plant adds an attractive touch to the landscape with its showy lavender flowers. The flowers can also be used as a cut flower in floral arrangements. In addition, parts of the plant have been used in traditional medicine by native people to treat sore throats, coughs, and various respiratory ailments. The plant contains glycosides, which are believed to give the plant its medicinal properties.
Light Requirements
The Penstemon watsonii Gray ssp. laxus (A. Nels.) Keck plant requires full sun to partial shade for healthy growth. It grows well in areas that receive at least 6-8 hours of direct sunlight each day. In areas with hotter climates, it may benefit from partial shade during the hottest part of the day.
Temperature Requirements
This plant thrives in cool to warm temperatures. It grows best in temperatures that range between 50 to 80 degrees Fahrenheit (10 to 26 degrees Celsius). Extremely high temperatures can cause stress and damage to the plant, so it is important to provide partial shade or other forms of temperature regulation in hotter climates.
Soil Requirements
Penstemon watsonii Gray ssp. laxus (A. Nels.) Keck must be grown in well-draining soil that is rich in nutrients. The plant prefers sandy loam, but can also grow in rocky or clay soils. It prefers a soil pH range of 6.0 to 7.5. If the soil is too acidic, adding agricultural lime may help to raise the pH level, while adding elemental sulfur can help to lower it. Regularly amending the soil with compost, manure, or other organic matter can help maintain soil fertility and support plant growth.
Cultivation methods for Penstemon watsonii Gray ssp. laxus (A. Nels.) Keck
Penstemon watsonii Gray ssp. laxus (A. Nels.) Keck can be grown in a range of soil types, including sandy loam, clay loam, and rocky soils. It requires well-draining soil with a pH range of 6.0-7.5
The plant is hardy in USDA zones 5-8 and can be grown in both full sun and partial shade conditions. It prefers cool summers and can tolerate frost and temperatures as low as -15°F.
Watering needs for Penstemon watsonii Gray ssp. laxus (A. Nels.) Keck
Penstemon watsonii Gray ssp. laxus (A. Nels.) Keck requires moderate watering. It is drought-tolerant, but consistent watering is recommended to promote healthy growth and flowering.
It is important to avoid overwatering as it can lead to root rot and other diseases. Watering should be reduced during the winter months to prevent waterlogging.
Fertilization for Penstemon watsonii Gray ssp. laxus (A. Nels.) Keck
Fertilization is not required for Penstemon watsonii Gray ssp. laxus (A. Nels.) Keck as it can grow in nutrient-poor soils. However, adding a balanced fertilizer during the growing season can promote healthier foliage and encourage flowering.
Choose a slow-release fertilizer and apply it once every two to three months. Follow the manufacturer's instructions for application rates.
Pruning for Penstemon watsonii Gray ssp. laxus (A. Nels.) Keck
Pruning is not mandatory for Penstemon watsonii Gray ssp. laxus (A. Nels.) Keck, as it has a natural compact growth habit. However, deadheading the spent flowers can promote continuous blooming.
If you want to shape the plant or control its size, prune it during the early spring when new growth begins. Remove any dead or damaged stems and trim back the lateral branches to the desired size.
Propagation Methods of Penstemon watsonii Gray ssp. laxus (A. Nels.) Keck
Propagation of Penstemon watsonii Gray ssp. laxus (A. Nels.) Keck can be done by various methods. Some of the common methods are described below:
Seed Propagation
The seeds of Penstemon watsonii Gray ssp. laxus (A. Nels.) Keck can be collected from the plant during the blooming season. The seeds should be sown in a well-prepared seedbed or a pot filled with a mixture of sand, loam, and peat. The pot or seedbed should be placed in a partially shaded area. The seeds will germinate within two to three weeks. Once the seedlings are large enough to handle, they can be transplanted into individual pots or a permanent location in the garden.
Vegetative Propagation
Penstemon watsonii Gray ssp. laxus (A. Nels.) Keck can also be propagated vegetatively through stem cuttings, division, or layering. Stem cuttings should be taken during the summer months. The cutting should be about 4 to 5 inches long, and the lower leaves should be removed. The cutting should be dipped in rooting hormone and planted in a pot filled with a mixture of sand and peat. The pot should be placed in a partially shaded area and kept moist until the cutting has rooted.
Division of Penstemon watsonii Gray ssp. laxus (A. Nels.) Keck can be done during the spring or fall months. The plant should be carefully dug up from the ground, and the root system should be divided into several sections. Each section should have a healthy shoot and a portion of the root system. The sections should be replanted in a well-prepared area of the garden.
Layering of Penstemon watsonii Gray ssp. laxus (A. Nels.) Keck can be done during the summer months. A low growing stem should be selected and bent towards the ground. A small section of the stem should be buried in the soil, leaving the tip exposed. The stem should be anchored to the ground with a small wire or peg. The buried section will start to grow roots, and once the plant has produced adequate roots, the stem can be cut from the parent plant and replanted in a well-prepared area of the garden.
Disease Management
Penstemon watsonii Gray ssp. laxus (A. Nels.) Keck is susceptible to specific diseases that can reduce its overall health and appearance. Here are some of the common diseases that may affect this plant and ways to manage them:
Phytophthora Root Rot
This disease is caused by the fungus Phytophthora and is characterized by wilted leaves, yellowing, and stunted growth. To manage this disease, avoid overwatering and poorly drained soils that provide a conducive environment for the fungus. Remove infected plants, sanitize equipment, and avoid planting in the same spot to reduce the spread of the disease.
Rust
Rust is a fungal disease that appears as yellow or orange pustules on the plant's foliage. To control rust, remove and destroy all infected leaves and stems. Fungicides can also be applied in severe cases to limit the spread of the disease.
Pest Management
Penstemon watsonii Gray ssp. laxus (A. Nels.) Keck is also susceptible to pests that can cause damage to the plant. Here are the common pests that may affect this plant and ways to manage them:
Aphids
Aphids are tiny insects that feed on the plant's sap, causing stunted growth, curled leaves, and yellowing. Remove the pests by washing them off with water, applying insecticidal soap, or introducing natural predators like ladybugs.
Spider Mites
Spider mites are common pests that feed on the plant's leaves, causing them to dry out and fall off. To control spider mites, spray the plant with a strong jet of water, regularly prune to remove infested leaves, and apply miticides in severe cases.
