Overview
Phlox glabriflora (Brand) Whitehouse ssp. tharpii (Whitehouse) Wherry is an herbaceous perennial plant that belongs to the Phlox family, Polemoniaceae. It is a sub-species of Phlox glabriflora, which is commonly known as Smooth Phlox. The plant is native to North America and specifically grows in the central United States.
Common Names
The plant has several common names, including Tharp’s Phlox, Smooth Phlox, and White River Phlox. These names are derived from the plant’s appearance and origin.
Appearance
Phlox glabriflora (Brand) Whitehouse ssp. tharpii (Whitehouse) Wherry is a clumping plant that can grow up to 1.5 feet in height and spread about 1 foot in width. The plant has a fibrous root system that clings to the soil. The leaves of the plant are small, narrow, and lance-shaped. They are found in opposite arrangement along the stem. The plant produces white flowers that have a diameter of about one inch. The flowers appear in clusters at the end of the stem and bloom during the late spring to early summer season.
Uses
Phlox glabriflora (Brand) Whitehouse ssp. tharpii (Whitehouse) Wherry is a beautiful plant that is commonly used in gardens, borders, and rock gardens. Its small size and showy flowers make it an excellent choice for small gardens or containers. The plant is also used for erosion control due to its fibrous root system that helps to stabilize soil. Additionally, the plant attracts butterflies and hummingbirds to the garden and can be used to add color and life to any landscape.
Light Requirements
Phlox glabriflora requires full sunlight to thrive. This plant cannot tolerate shade or even partial shade and may only survive if grown in an area with six hours or more of direct sunlight per day. The intensity of the light also affects the growth of Phlox glabriflora, and in areas with extremely hot summer temperatures, partial shade may be necessary to prevent the plant from drying out.
Temperature Requirements
The plant is suited to grow in areas with cold winters and hot summers. It tolerates both extreme heat and cold, so long as it is not exposed to extreme temperatures for extended periods. Temperatures that fall between the range of 50°F to 85°F are optimal. Temperatures above 90°F can damage the plant, and temperatures below freezing can lead to death.
Soil Requirements
Phlox glabriflora grows best in well-drained soil. The soil should be slightly acidic, with a pH of 5.5 to 7. Weed growth should be controlled in the area to avoid competition for nutrients and water. The plant prefers fertile soils and may require regular fertilization to maintain healthy growth. Organic matter can help to improve soil fertility and ensure adequate soil moisture retention.
Cultivation Methods
Phlox glabriflora (Brand) Whitehouse ssp. tharpii is a hardy perennial plant that is native to the United States. It prefers a cool climate and grows well in full sun to partial shade. The plant can be grown from seed or propagated through division. It should be planted in well-draining soil with a pH range of 6.0 to 7.0. The plant should be spaced out 18 to 24 inches apart to allow for proper air circulation.
Watering Needs
Phlox glabriflora (Brand) Whitehouse ssp. tharpii requires consistent moisture to grow properly. It should be watered regularly, ensuring that the soil is thoroughly soaked. However, overwatering can cause root rot and other issues. Watering should be reduced during the dormant season to prevent excess moisture accumulation.
Fertilization
Phlox glabriflora (Brand) Whitehouse ssp. tharpii should be fertilized annually in the spring with a balanced fertilizer. Fertilizer should be applied at a rate of 1 pound per 100 square feet. It is important not to over-fertilize as this can cause excessive growth and weakens the plant's resistance to pests and diseases.
Pruning
Phlox glabriflora (Brand) Whitehouse ssp. tharpii should be pruned after flowering to remove dead or diseased leaves and stems. This promotes the growth of new foliage and helps the plant to maintain its shape. The plant can also be pinched back in early summer to encourage bushier growth and more extensive blooming.
Propagation of Phlox glabriflora ssp. Tharpii
Phlox glabriflora ssp. Tharpii, commonly known as Tharp's phlox, is a perennial plant with showy pink to purple flowers. The plant is native to the southern regions of the United States and is well suited to growing in gardens and landscapes in USDA hardiness zones 5 to 8.
Propagation methods of Phlox glabriflora ssp. Tharpii
Phlox glabriflora ssp. Tharpii can be propagated by several different methods:
Seed Propagation
One of the most common methods for propagating P. glabriflora ssp. Tharpii is through seed propagation. Collect seeds from the plant in the late summer or early fall after the seed pods have dried and turned brown. Store the seeds in a cool and dry place until planting in the following spring. Sow seeds directly into well-prepared soil in a sunny location after the danger of frost has passed. The seeds will germinate in 10 to 20 days and should be thinned to a spacing of 6 to 12 inches once they are large enough to handle.
Division Propagation
Division propagation is another effective way to propagate P. glabriflora ssp. Tharpii. In early spring, as new growth begins to appear, carefully dig up the plant and divide it into smaller sections using a sharp knife or a garden fork. Each section should have several healthy shoots and a good root system. Replant the divisions in a location with well-drained soil and adequate sunlight, spacing them 6 to 12 inches apart.
Cutting Propagation
Cutting propagation can also be used to propagate P. glabriflora ssp. Tharpii. Take 4 to 6 inch cuttings from the parent plant in early summer and remove the lower leaves. Dip the cut end of the cutting in rooting hormone powder and plant in a container filled with a well-draining potting mix. Place the container in a warm and sunny location and water consistently. The cuttings should root in 4 to 6 weeks and can be transplanted into the garden once they have become established.
Regardless of the propagation method used, newly propagated Phlox glabriflora ssp. Tharpii should be watered regularly and provided with adequate sunlight and soil nutrients. With proper care, the plants will thrive and produce beautiful flowers year after year.
Disease Management
Phlox glabriflora ssp. tharpii is susceptible to various diseases, including:
- Botrytis blight: This fungal disease causes plant decay, leading to leaf spots and stem rot. To manage it, apply fungicides regularly and avoid overhead irrigation.
- Mildew: Powdery mildew is common in phlox, causing a white powdery growth on plant surfaces. To avoid this, provide good air circulation and avoid overcrowding of plants. Apply fungicides early to avoid extensive damage.
- Root rot: This is caused by various fungal pathogens and affects the plant's roots, causing wilt and death. Increase soil drainage, avoid overwatering, and treat with appropriate fungicides.
Pest Management
Common pests that attack Phlox glabriflora ssp. tharpii include:
- Aphids: These tiny insects suck the sap from plant leaves and shoots, causing stunted growth and deformities. Apply insecticidal soap or neem oil to control infestation.
- Spider mites: These pests cause yellowing, leaf drop, and webbing. Wash plants with a strong stream of water and use insecticides where necessary.
- Thrips: These pests feed on plant sap and cause silvery lines and distorted leaves. Introduce natural predators like lacewings or apply insecticides to manage infestation.
