Origin
Oenothera macrocarpa Nutt. var. oklahomensis (J.B.S. Norton) Reveal, commonly known as Oklahoma evening-primrose, is a flowering plant species that is native to North America, specifically the central and southern regions of the United States.
Common Names
The plant is also called bigfruit evening-primrose due to its large fruit capsules, and often referred to by its common name the Oklahoma evening-primrose. It is sometimes also called the Ozark Sundrops.
Uses
The Oklahoma evening-primrose has several medicinal uses. The plant has been used for centuries in Native American medicine to treat a variety of ailments, such as stomach aches, sore throats, and coughs. The roots of the plant were boiled and the decoction was consumed to treat these ailments. The plant is also believed to have anti-inflammatory properties and has been used to treat skin conditions.
General Appearance
Oenothera macrocarpa Nutt. var. oklahomensis (J.B.S. Norton) Reveal is a perennial herb that grows up to 3 feet tall. The plant has a branching stem that arises from a woody base. The leaves of the plant are arranged in a rosette at the base, and get smaller as they ascend the stem. The leaves are lance-shaped, and have a slightly toothed margin. The flowers of the plant are large, bright yellow, and bloom during late spring and throughout the summer. The plant produces a unique fruit capsule that is up to 4 inches long and contains hundreds of tiny, reddish-brown seeds.
Light Requirements
Oenothera macrocarpa Nutt. var. oklahomensis (J.B.S. Norton) Reveal needs full sunlight exposure to grow optimally. Therefore, it is recommended to plant this species in areas that receive a minimum of six hours of direct sunlight each day. Additionally, this plant may require some protection from high-intensity sunlight or scorching heat, especially during hot weather.
Temperature Requirements
This species is well adapted to a wide range of temperatures, including hot, dry summers and cold winters. It grows best in areas with temperatures ranging between 60 and 80 degrees Fahrenheit. While it can also survive temperatures below freezing, it usually becomes dormant and regrows in spring when warmer temperatures arrive.
Soil Requirements
Oenothera macrocarpa Nutt. var. oklahomensis (J.B.S. Norton) Reveal thrives in well-draining, sandy soils rich in organic matter. It prefers soils that are neutral to mildly acidic, with a pH ranging between 6.5 and 7.5. However, it can also grow in slightly alkaline soils with a pH of up to 8.5. It is important to avoid planting this species in heavy, clay soils, which retain too much moisture and can cause root rot or other fungal diseases.
Cultivation Methods
Oenothera macrocarpa Nutt. var. oklahomensis (J.B.S. Norton) Reveal, commonly known as Oklahoma evening primrose, prefers well-drained soil and full sun exposure. It is a low maintenance plant that doesn't require regular watering. It can tolerate high temperatures and drought conditions, making it an ideal plant for hot and dry areas. It can be grown from seeds or propagated through division in early spring.
Watering Needs
Oklahoma evening primrose doesn't require frequent watering. It is recommended to water deeply once a week during the growing season to encourage a deep root system. However, be careful not to overwater as this can lead to root rot. During the winter months, reduce watering to once a month.
Fertilization
Oklahoma evening primrose doesn't require regular fertilization if grown in nutrient-rich soil. However, if the plant is grown in poor soil, it can benefit from a slow-release fertilizer once a year in early spring. Use a balanced fertilizer with an NPK ratio of 10-10-10 or 5-10-5. Be sure to follow the recommended dosage on the fertilizer label.
Pruning
Oklahoma evening primrose doesn't require regular pruning. However, if the plant becomes unruly or leggy, it can be pruned back by one-third in early spring. This will encourage new growth and a more compact shape. Deadheading spent blooms can also encourage new blooms to appear and extend the flowering season.
Propagation of Oenothera macrocarpa Nutt. var. oklahomensis
Oenothera macrocarpa Nutt. var. oklahomensis, commonly known as Oklahoma evening primrose, is a perennial wildflower native to the Great Plains region of North America. Propagation of this plant can be done either by seed or by division.
Propagation by Seed
Propagation by seed is an easy and commonly used method for growing Oklahoma evening primrose. The seeds can be sown directly in the ground in the spring when the soil temperature reaches around 60°F (15°C) or started indoors four to six weeks before the last frost date. To start seeds indoors, use a well-draining potting mix and keep it moist but not soggy. Once the seedlings have grown several true leaves, they can be transplanted into larger pots or into the ground outside.
Propagation by Division
Propagation by division involves separating the plant's roots into smaller sections and replanting them. This method is best done in the spring or fall when the plant is not actively growing. To propagate by division, carefully dig up the plant, being sure to keep the root system intact. Using a sharp knife or garden shears, cut the roots into smaller sections, each containing at least one growing point or shoot. Replant the divisions immediately at the same depth they were originally growing and water well. Make sure to keep the soil moist until the divisions have established themselves.
Disease Management
Oenothera macrocarpa Nutt. var. oklahomensis is relatively disease-resistant; however, certain diseases may still affect the plant. The following are some of the most common diseases that might affect this plant and ways to manage them:
- Powdery mildew: This fungal disease appears as white or grayish powdery spots on the leaves of the plant. To manage this disease, remove infected plant parts immediately and treat the plant with a fungicide.
- Botrytis blight: This fungal disease affects the flowers of the plant and causes them to turn brown and mushy. To manage this disease, remove all infected plant parts and avoid overhead watering.
- Verticillium wilt: This fungal disease causes leaves to wilt and turn yellow. Infected plants should be removed and destroyed immediately to avoid spreading the disease to healthy plants.
Pest Management
Oenothera macrocarpa Nutt. var. oklahomensis is also relatively pest-resistant, but some common pests might still infest the plant. Here are some of the most common pests that might affect this plant and ways to manage them:
- Aphids: These small, soft-bodied insects can suck the sap from the plant, causing it to weaken and become stunted. To manage aphids, use insecticidal soap or a strong stream of water to dislodge them from the plant.
- Spider mites: These tiny insects can cause yellow stippling on the leaves of the plant and cause it to become weak. To manage spider mites, regularly mist the plant with water to increase humidity and use insecticidal soap.
- Cutworms: These caterpillar-like insects can sever the stems of the plant at ground level. To manage cutworms, remove all garden debris from the area around the plant, and use insecticides that contain Bacillus thuringiensis (BT).
