Overview
Opuntia whipplei Engelm. & Bigelow var. spinosior Engelm. is a species of cactus that is native to the southwestern United States and northern Mexico. It is also commonly known as Whipple's prickly pear or the Mojave prickly pear.
Appearance
This plant is a low-growing, spine-covered cactus that forms sprawling mounds up to 2 meters wide. It can have flat and broad pads that can grow up to 20 centimeters long and 15 centimeters wide. The pads are typically blue-green in color and can turn reddish-purple in colder temperatures. Its fruits are spiny and reddish-orange in color.
Uses
The pads of Opuntia whipplei Engelm. & Bigelow var. spinosior Engelm. are edible and can be used in various culinary dishes. They can be roasted and used in salads or cooked in stews. The fruits are also edible and can be eaten raw or made into jams and jellies. The plant is widely used in traditional medicines to treat various ailments such as wounds, burns, and digestive disorders. Additionally, the spiny pads and fruits can be used as a dye source for textiles.
Light Requirements
Opuntia whipplei Engelm. & Bigelow var. spinosior Engelm. is a desert plant that thrives in full sun. When planted in areas with partial shade, it may not grow as tall, and its flowering and fruiting may be scarce. Therefore, it is recommended that this plant be grown in areas with direct sunlight for at least six hours.
Temperature Requirements
Opuntia whipplei Engelm. & Bigelow var. spinosior Engelm. is native to the southwestern United States and northern Mexico where it is exposed to a range of temperatures. It can withstand temperatures as low as 0 degrees Fahrenheit (-18 degrees Celsius) and as high as 115 degrees Fahrenheit (46 degrees Celsius). However, the plant's optimal temperature range for growth is between 85-100 degrees Fahrenheit (29-38 degrees Celsius).
Soil Requirements
Opuntia whipplei Engelm. & Bigelow var. spinosior Engelm. prefers well-drained soils that are slightly acidic to slightly alkaline. The plant can grow in sandy loam, clay loam, and rocky soils. It can tolerate soils with low nutrient content and is drought-tolerant once established. Additionally, the plant's origins in rocky areas make it an excellent choice for rock gardens and xeriscaping.
Cultivation methods
Opuntia whipplei Engelm. & Bigelow var. spinosior Engelm. is a drought-tolerant cactus and is relatively easy to grow. It prefers a well-draining soil mixture rich in organic matter and sand. Planting in a pot with drainage holes or a raised bed will help prevent waterlogging that can lead to root rot.
The cactus can grow in full sun or partial shade, though it prefers full sun. It grows best in warm temperatures around 70-85°F (21-29°C).
Watering needs
When established, Opuntia whipplei Engelm. & Bigelow var. spinosior Engelm. requires infrequent watering. During the growing season, water once every three weeks. Wait until the soil is dry to the touch before watering. Reduce watering in the winter months to once a month or less.
Overwatering can lead to root rot and eventually death of the plant. It is better to underwater than to overwater.
Fertilization
Fertilization should occur only during the cactus's active growing season in the spring and summer months. Use a slow-release fertilizer or a cactus-specific fertilizer at half-strength during this time. Fertilizer application during the dormant months is not necessary.
Pruning
Opuntia whipplei Engelm. & Bigelow var. spinosior Engelm. rarely requires pruning. Remove any damaged or diseased pads using sterilized pruning shears. Remove any pads that are blocking light or air circulation to promote healthy growth. Pruning should only be done during the spring and summer months.
Propagation of Opuntia whipplei Engelm. & Bigelow var. spinosior Engelm.
Opuntia whipplei Engelm. & Bigelow var. spinosior Engelm., commonly referred to as Whipple's cholla or hanging chain cholla, is a popular cactus species among gardeners for its unique appearance and hardiness. Propagation of this cactus species can be done through several methods, including:
Seed Propagation
Seed propagation is a common method used to grow Opuntia whipplei Engelm. & Bigelow var. spinosior Engelm. from scratch. You can collect seeds from mature and healthy plants during its blooming period. Once you have collected the seeds, make sure to remove debris or damaged seeds, then sow them in well-draining soil that is moist but not wet. The seeds should be planted at a depth of about 0.5 inches and should be kept in a warm and bright area with temperatures above 65°F. Within several weeks, the seeds will germinate, and once they outgrow their starter pots, you can transplant them into their permanent location.
Vegetative Propagation
Vegetative propagation is a faster method used to increase numbers of Opuntia whipplei Engelm. & Bigelow var. spinosior Engelm. than seed propagation. This method involves taking a cutting from a mature plant and transplanting it. The cutting should be healthy, mature, and free from pests or diseases. Using a sharp, sterile knife, cut a section of the stem at least 6-8 inches long, dry it, and dip it into root hormone powder to boost the chances of rooting. Allow the cutting to dry for a day or two before planting it in well-draining soil. Water it sparingly for a few weeks and gradually increase the watering routine until the new plant is well-established.
Grafting Propagation
Grafting Propagation is another method of propagating Opuntia whipplei Engelm. & Bigelow var. spinosior Engelm. In this method, a cutting from a mature cactus is grafted onto a rootstock of another succulent plant species. The rootstock should have compatible features with your cactus plant. This method has a high success rate and ensures that the new cactus takes the characteristics of the parent plant. However, this method requires technical know-how and may not be the best approach for novice gardeners.
Disease Management
Opuntia whipplei Engelm. & Bigelow var. spinosior Engelm. is generally a hardy plant and is not prone to many diseases. However, some common diseases that can affect the plant are:
- Phytophthora root rot: it is a fungal disease that attacks the plant's roots and can cause wilting, yellowing, and death of the plant. To manage this disease, it is important to avoid over-watering and ensure the plant is growing in well-draining soil.
- Bacterial soft rot: it is a bacterial disease that causes the plant to rot and emit a foul smell. This disease is often caused by poor cultural practices and can be avoided through proper sanitation and handling of the plant.
- Anthracnose: it is a fungal disease that can cause spots on the leaves and fruits of the plant. To manage this disease, affected leaves and fruits should be removed, and a fungicide can be used to prevent further spread.
Pest Management
Opuntia whipplei Engelm. & Bigelow var. spinosior Engelm. can be affected by various pests, but the most common ones are:
- Cactus moth: it is a larva that feeds on the plant's flesh, causing black lesions and tissue damage. To manage this pest, natural predators like parasitic wasps can be introduced to control the population.
- Red spider mites: they are tiny pests that can cause yellowing and stunted growth of the plant. To manage this pest, the plant should be regularly cleaned and treated with an insecticidal soap or neem oil.
- Cochineal scale: it is a pest that feeds on the plant's sap and can cause yellowing and wilting of the plant. To manage this pest, the plant can be sprayed with insecticidal soap or neem oil.
