Overview
Crotalaria stipularia, commonly known as sunn hemp, is a tropical, fast-growing legume that is native to India and Southeast Asia. It belongs to the Fabaceae (pea) family and is widely cultivated as a forage crop and as a green manure in many parts of the world. It is also used in traditional medicine to treat various ailments.
Appearance
Sunn hemp is an annual plant that can grow up to 3 meters tall. It has a deep taproot and a strong, upright stem that is green or reddish-brown in color. The leaves are alternate, trifoliate, and ovate with stipules that are large and leaf-like. The flowers are bright yellow and are borne in elongated racemes that can be up to 30 cm long. The plant produces seed in pods that are up to 5 cm long and contain 10-20 seeds each.
Uses
Sunn hemp is widely cultivated as a forage crop and as a green manure. It is a good source of high-quality protein and is used as a feed for livestock. It is also an effective cover crop that improves soil fertility by fixing nitrogen and suppressing weed growth. Sunn hemp is also used in traditional medicine to treat various ailments such as fever, dysentery, and rheumatism. The plant contains bioactive compounds such as flavonoids, alkaloids, and phenols that have antimicrobial, anti-inflammatory, and antioxidant properties.
Common Names
Sunn hemp is known by various names depending on the region or country. Some of the common names include Bengal hemp, Bombay hemp, brown hemp, Indian hemp, sann-hemp, and Madras hemp.
Light Requirements
The plant Crotalaria stipularia Desv. requires full sun exposure for its normal growth and development. The plant usually grows in open fields, grasslands, and sunny slopes where there is no shading from surrounding trees or plants. Under shaded conditions, the growth rate of the plant is slow, and the plant tends to grow tall and slim to reach sunlight.
Temperature Requirements
The plant Crotalaria stipularia Desv. is typically found growing in warm and tropical regions. The plant can tolerate high temperatures ranging between 21 to 33 degrees Celsius. However, the plant cannot tolerate cold weather, and frost can kill the plant. The minimum temperature required for the plant to grow is 20 degrees Celsius.
Soil Requirements
The plant Crotalaria stipularia Desv. can grow in a wide range of soils, but it prefers well-drained soils with good fertility. The plant can grow in sandy, loamy, and clay soils as long as they have neutral to acidic pH levels ranging from 5.5 to 7.0. The plant requires adequate water drainage to prevent waterlogging. The plant is also sensitive to saline soils and cannot grow in such conditions.
Cultivation Methods
Crotalaria stipularia Desv., commonly known as rattlebox, is a flowering plant native to Africa but can be grown in other regions as well. To cultivate this plant, start by selecting a suitable site. The plant can thrive in well-drained soil with full sun or partial shade. It is ideal to plant the seeds in spring or summer, and the plant will germinate in 10 to 14 days.
After sowing the seeds, cover them lightly with a thin layer of soil, and then water gently. You can also propagate the plant by stem cutting that is planted during the spring. Water the plant regularly, especially when the soil feels dry. Avoid overwatering the plant as it can cause root rot.
Watering Needs
Proper watering is crucial for the growth and development of Crotalaria stipularia Desv. During the growing season, water the plant when the top inch of soil gets dry. Keep an eye on the plant during hot temperatures as it may need more watering to prevent it from drying out. It's best to water the plant early in the morning to give it sufficient time to absorb moisture before it evaporates during the day.
It is essential to note that rattlebox plants are drought-resistant and can adapt to low moisture levels. Therefore, overwatering can lead to root rot and fungal diseases, so be cautious not to overwater the plant.
Fertilization
Crotalaria stipularia Desv. is a relatively low-maintenance plant that requires minimal fertilization. Apply a balanced, slow-releasing fertilizer during the growing season to provide the plant with enough nutrients for growth. You can use a 10-10-10 or 20-20-20 granular fertilizer or a liquid organic fertilizer for better results.
Apply the fertilizer once in the late spring and again in the late summer, following the instructions on the package label. Too much fertilizer can cause the plant to grow too fast, resulting in weak stems and poor flower growth.
Pruning
Pruning Crotalaria stipularia Desv. is not necessary, but it can help manage the plant's growth and shape. Deadhead the spent flowers to encourage new growth and prevent the plant from becoming too leggy. Cut the plant back in late winter or early spring to remove any dead or damaged stems.
You can also prune the plant to promote bushier growth. Pinch the tips of the stems during the growing season to encourage branching and fuller growth.
Propagation of Crotalaria stipularia Desv.
Crotalaria stipularia Desv. is commonly known as the sunn hemp. It is an annual or short-lived perennial plant that belongs to the Fabaceae family. The plant is commercially propagated for its cover crop benefits. Crotalaria stipularia Desv. can be propagated through various methods such as seeds, cuttings, and divisions.
Propagation through seeds
Seeds are the most common propagation method of Crotalaria stipularia Desv. They can be sown indoors or directly in the field. For indoor sowing, fill a container or pot with a well-draining potting mix. Sow the seeds at a depth of 1 inch and keep the soil consistently moist. The ideal temperature for germination is 75°F. Seeds typically germinate within 5-7 days.
For direct sowing in the field, prepare the soil by removing weeds and debris. Sow the seeds at a depth of 1 inch and cover them lightly with soil. Keep the soil moist until the seedlings emerge. Thin the seedlings to 6-12 inches apart.
Propagation through cuttings
Cuttings are another propagation method for Crotalaria stipularia Desv. Take stem cuttings from healthy plants during the growing season. The cuttings should be 4-6 inches long and should have at least 2-3 leaf nodes. Remove the lower leaves and dip the cut ends in rooting hormone. Plant the cuttings in a well-draining potting mix and keep the soil consistently moist. The cuttings should root within 2-3 weeks.
Propagation through divisions
Crotalaria stipularia Desv. can also be propagated through division. Divide the plant in early spring before new growth appears. Carefully dig up the plant and separate the roots into several clumps. Replant the clumps in a well-draining soil mixture. Water the plants regularly until they become established.
Disease Management
Crotalaria stipularia Desv., commonly known as Sun Hemp, may be affected by various diseases that could harm the plant. To prevent the outbreak of diseases, growers should practice good agricultural practices.
One of the prevalent diseases that could infect crotalaria stipularia is the fungal disease called powdery mildew. Afflicted plants manifest white or grayish powdery patches on the leaves, stems, and flowers. To avoid this fungal disease, ensure proper air circulation around the plant, avoid foliage wetting during watering, and remove and dispose of diseased plant matter properly.
Another common disease that could affect crotalaria stipularia is root rot. Root rot is caused by different soil-borne fungi that attack the plant's roots, causing them to decay. Afflicted plants exhibit wilting, stunted growth, and yellowed leaves that eventually die. To manage root rot, good soil drainage is essential. Ensure that the soil is not waterlogged, avoid over-irrigation, and ensure proper soil aeration around the plant.
Pest Management
Crotalaria stipularia Desv. may face various pests that could cause significant damage to the plant. To prevent pest outbreaks, crop management practices should be observed, and Integrated Pest Management (IPM) approaches are employed.
One of the common pests that attack crotalaria stipularia is the caterpillar. Caterpillars feed on the plant's foliage, sometimes leading to defoliation and reduced plant growth. To manage caterpillars, handpicking could offer a great solution. Encouraging natural predators of the pests, like birds, could also be helpful.
The soybean looper is another pest that could damage crotalaria stipularia. They feed on the plant's foliage, leading to skeletonization and reduced plant growth. Applying Bacillus thuringiensis (Bt) or spinosad products can help control the soybean looper infestation.
The Aphid is another pest that could harm crotalaria stipularia. They feed on the plant's foliage, causing leaf curling, stunted growth, and reduced yield. The aphid also produces honeydew that supports the growth of sooty mold. Applying insecticidal soap or neem oil could help control the aphid infestation.
