Clasping milkweed (Asclepias amplexicaulis) is a flowering plant species native to parts of the eastern United States. It is a rare milkweed and is protected in some states. Clasping milkweed blooms in summer and grows in dry prairies and fallow fields.
I. Appearance and Characteristics
Asclepias amplexicaulis, the blunt-leaved milkweed, clasping milkweed, or sand milkweed, is a species of flowering plant in the subfamily Asclepiadoideae (Apocynaceae). It is endemic to the United States, where it is mostly found east of the Great Plains. It grows in dry prairies, savannas, open woods, and fallow fields, usually in sandy soil.
It grows 1–3 ft (0.30–0.91 m) high and produces flowers in the summer.
This plant was eaten as food historically. However, it contains a poison dangerous to humans and livestock, so caution must be used if ingesting this plant.
II. How to Grow and Care
Clasping milkweed typically flourishes with minimal intervention, making it an easy-care plant ideal for those who appreciate low-maintenance gardening. It thrives in well-drained soils and requires full sun exposure to promote healthy growth and flowering. Special care should be taken to provide ample space for root development. Watering should be moderate, as clasping milkweed is drought-tolerant and excessive moisture may lead to root rot.
Sunlight
Clasping milkweed thrives in conditions of full sun, having evolved to capitalize on direct sunlight for optimal growth and robust health. This plant needs substantial daily exposure to maintain its vigor and facilitate vital processes such as photosynthesis. While clasping milkweed tolerates partial sun, insufficient light may lead to suboptimal development, with potential impacts on flowering and resilience. Adaptive in nature, clasping milkweed exhibits traits to maximize light absorption, but for ideal cultivation, planting should be in open areas that receive unfiltered sunlight for the majority of the day, as it is mostly an outdoor species.
Temperature
It can be planted in most areas if you would remove it after planting for just a year. The suitable temperature range for its growth is 18 to 30 ℃. It can tolerate up to 35 ℃ and withstand a minimum temperature of 8 ℃ in winter. It will stop growing below 5 ℃ and gradually die below 0 ℃.
Clasping milkweed likes a humid environment, so provide it with sufficient water in all seasons except winter. If the air humidity is too low, the leaves will gradually lose their luster.
Watering
Thriving in its native grasslands, clasping milkweed is adapted to periodic droughts, showcasing a preference for drier conditions. It requires watering every week to maintain its health without over-saturating the soil. As an herbaceous perennial commonly grown outdoors, clasping milkweed demonstrates resilience by efficiently utilizing water during its active growing season before entering dormancy.
Soil
Clasping milkweed adapts to various soil environments. The most suitable soil is slightly acidic and well-drained. If the planting soil is sticky, add some leaf mold, organic fertilizer, river sand, or a similar compound and stir evenly to improve soil texture. You can also add a little soil at the base of the plant to encourage growth. This will prevent plant lodging and provide more nutrients to the roots.
Fertilizing
Clasping milkweed does not require much fertilizer, so doesn’t need to be fertilized often. After flower buds appear, a little phosphate fertilizer ensures growth during the flowering period. Apply organic fertilizer once before winter. This will increase the plant’s ability to withstand the harsh environment and survive the season. During dormancy, the physiological activities of clasping milkweed will slow down or even stop. Overfertilization causes excessive accumulation of nutrients, which leads to root rot. Hence, stop fertilization after the plant enters winter dormancy.
Planting Instructions
Clasping milkweed can be sown in spring, planted in flower pots or placed directly in the garden. You can keep seeded pots indoors. Sow at warmer temperatures for best results. The seeding depth is about 2.5 cm. Press the soil slightly, so that the soil and the seed make firm contact. After sowing, water the seeds thoroughly. Generally, they will germinate after two weeks with a germination rate of about 80-90%.
When the seeds in the pot germinate with 2-3 pairs of leaves, they can be transplanted into the ground. When transplanting, keep the soil on the roots to avoid damaging the root system. Remember to water thoroughly after planting. Clasping milkweed grows best in a ventilated environment, such as by a road, wall, or window. Without good ventilation, pests will appear, which can threaten the plant’s growth.
Pruning
Regularly remove infected plants and wilting leaves to keep clasping milkweed healthy. If you are located in a tropical or subtropical climate, you can cut off branches in early spring to promote germination. Given the high toxicity of clasping milkweed, wear gloves when handling plants to prevent poisoning. Keep clasping milkweed away from children, avoid direct contact, and do not eat the plant.
Propagation
Clasping milkweed often sprouts many small seedlings. In early spring, you can dig out the seedling bunch. Use a sharp clean knife to divide the root into several parts and plant them separately.