Asclepias purpurascens, the purple milkweed, is a herbaceous plant species. It is in the genus Asclepias, making it a type of milkweed. It is native to the Eastern, Southern and Midwestern United States similar to the range of the common milkweed (Asclepias syriaca). The plant gets its name from the flowers that first develop a pink color but then turn darker purple as they mature. Unlike common milkweed, purple milkweed prefers some shade and is considered a plant of partial shade. It is also considered an indicator of oak savanna, especially in Wisconsin. The species rarely produces seed pods which are smooth instead of the rough warty ones produced by common milkweed.
Purple milkweed is fairly disease-resistant and generally does not suffer from illnesses. However, it can be affected by pests and diseases present in its surroundings. Such infections are usually mild. For care, the plant requires moderate maintenance. Regular pruning is needed to keep a neat appearance and support healthy growth. Fertilizing may also encourage flowering. Purple milkweed is suitable for anyone with outdoor space, such as a garden or patio, and does not require extensive gardening experience. When grown indoors it may need additional care.
How to keep Asclepias Purpurascens.
Light
Purple milkweed prefers sites with abundant sunlight, although it can tolerate areas where light becomes softly diffused over the course of the day. Coming from habitats defined by plentiful sun, its health and growth may suffer if it gets too little light or, on the other hand, too much.
Water
Purple milkweed, native to the grasslands of North America, thrives in drier conditions and should be watered every 1-2 weeks, allowing the soil to partially dry out between waterings. Indoors, it flourishes when provided with plenty of light and well-draining soil. During its active growth phase, it requires consistent moisture to produce vibrant flowers.
Humidity
This plant will thrive in moderate humidity, which is probably the level in your home. However, misting it a few times a week can be very beneficial. Make sure the room has good ventilation.
Temperature
Purple milkweed comes from temperate regions and does best in temperatures of 32 to 95°F (0 to 35℃). It favors full sun, which helps it withstand tough conditions and adapt to seasonal temperature shifts. Rapid dips below freezing should be avoided.
Fertilizer
The best time to fertilize a Purple milkweed is in early spring, when it is coming out of dormancy and starting active growth. Fertilizing supplies essential nutrients for healthy development. Although Purple milkweed has relatively low fertilizer requirements, an annual application can boost its survival and encourage better, longer-lasting blooms.
Pruning
Purple milkweed benefits greatly from selective pruning. To enhance its health, remove spent flowers after they bloom and eliminate dead stems in early spring. For shaping, prune the plant in late spring. By pruning regularly, you encourage bushy growth and an abundance of blooms. Always use clean, sharp tools to minimize stress on the plant and reduce the risk of disease.
Botanical profile.
- Plant Type
- Herb
- Life Cycle
- Perennial
- Genus
- Asclepias
- Family
- Apocynaceae
- Hardiness Zone
- 3-9
- Mature Height
- 61 cm to 91 cm
- Mature Spread
- 30 cm to 91 cm
- Leaf Color
- Green, Red
- Leaf Type
- Deciduous
- Flower Color
- Purple, Lavender
- Flower Size
- 2.54 cm
- Bloom Time
- Late spring, Early summer, Mid summer
- Planting Time
- Spring
- Harvest Time
- Late summer, Early fall, Mid fall
Other names.
Reader questions.
How should I water my Purple milkweed?
To best care for the Purple milkweed, use filtered water at room temperature. Tap water may have harmful particles, so it's better to avoid using it. The Purple milkweed is accustomed to warmth, so using cold water can be a shock to its system. Avoid overhead watering to prevent foliage complications. Instead, thoroughly soak the soil with filtered room temperature water. This helps the roots stay moisturized and spread through the soil to gather nutrients.
Why is it important to add fertilizer to my Purple milkweed?
To ensure vibrant and healthy leaves on your Purple milkweed, fertilization is crucial. By properly fertilizing, you can maintain consistent color and a healthy texture in the leaves. Additionally, fertilization goes beyond surface-level benefits. It promotes the growth of new roots and helps maintain the existing root system. This not only keeps your plant healthy in the present but also enhances its ability to absorb soil nutrients in the long run.
What are the sunlight requirements for Purple Milkweed?
Purple Milkweed requires full sun, which amounts to more than 6 hours of sunlight daily, but it can also thrive in partial sun, approximately 3-6 hours of sunlight. It's crucial to monitor how sunlight moves through your garden to find the ideal location that offers a balance of light and shade, ensuring the plants' health and happiness.
What is the native climate of Purple Milkweed?
Purple milkweed is native to temperate climates, thriving in a temperature range from 32 to 95°F (0 to 35°C). It is capable of acclimating to harsh conditions through full sunlight exposure, making it adaptable to seasonal temperature variations. While it has strong cold resistance and typically does not require special frost protection measures, unexpected drops below freezing should be avoided to maintain its health.
What should I do if I give my Purple milkweed too much or too little water?
Overwatering and underwatering can harm your Purple milkweed, but overwatering is more common and poses greater risks. When the plant receives excessive water, its stems and leaves may wilt and turn yellow. Prolonged overwatering can also lead to diseases like root rot, mold, and mildew, which can be fatal to your plant. On the other hand, underwatering is less likely for the Purple milkweed as it is somewhat drought-tolerant. However, it is still possible, and when it occurs, the leaves may become brittle and brown. To care for your Purple milkweed, it is important to recognize the signs of overwatering early. Some diseases caused by overwatering may be irreversible if prompt action is not taken. If you notice initial signs of overwatering, reduce your watering schedule and check the soil's drainage. If the soil drains poorly, replace it with a loose, well-draining potting mix. Conversely, if you observe signs of underwatering, simply increase your watering frequency until the signs improve.
When should I fertilize my Purple milkweed for the best results?
If you grow Purple milkweed outdoors, new growth will appear in early spring, indicating it's time to fertilize. Usually, a single application of fertilizer in the spring is sufficient for the plant to thrive. However, if you want to promote maximum growth, you can fertilize multiple times during spring and early summer, ideally once every month to a month and a half.
How does Purple Milkweed respond to different light conditions?
Purple Milkweed prefers abundant sunlight but is capable of adapting to areas where light is more diffuse. Originating from well-lit habitats, its well-being and growth may falter if it's either under or overexposed to light. For indoor plants, when natural light is insufficient, particularly during winter or in less sunny areas, artificial lighting can be a lifesaver by promoting healthier, more robust growth. Selecting the correct type of artificial light, like LED lights, and adjusting the light intensity (30-50W/sq ft for full sun plants, 20-30W/sq ft for partial sun, and 10-20W/sq ft for full shade plants), positioning (12-36 inches from the plant), and duration (8-12 hours daily) is essential.
How should Purple Milkweed be protected during extreme winter conditions?
During winters with temperatures expected to drop below -35°C, it is important to protect Purple Milkweed from the cold. This can be achieved by covering the plant with insulating materials such as soil or straw. Additionally, watering the plant abundantly before the first freeze of autumn is recommended. This ensures the soil remains moist and enters a frozen state, helping to prevent drought and water scarcity for the plant during the winter and early spring periods.
How often do I need to water my Purple milkweed?
If your Purple milkweed is in a pot, the most precise way to determine if it needs water is by checking the moisture level of the soil. Simply stick your finger into the soil, and if the top two to three inches are dry, then it's time to water it. If you have your Purple milkweed planted in the ground outdoors, you can use a similar method to test the soil. Again, if the top few inches of soil have dried out, it's time to water. Typically, during the spring and early fall, this plant will need watering about once a week. However, in extremely hot weather, you may need to increase watering to twice a week or more. Nevertheless, mature, well-established Purple milkweed has a remarkable ability to withstand drought.
When should I not use fertilizer on my Purple milkweed?
During late fall and winter, your Purple milkweed goes into a dormant phase and does not produce new growth. Therefore, avoid fertilizing it during this period. In spring and summer, if you decide to fertilize, gradually decrease the frequency as summer approaches because the growth rate of your Purple milkweed slows down. It is generally not advisable to fertilize your Purple milkweed during unusually hot weather or when the soil is extremely dry, as this can stress the plant and result in early death.
What are the primary symptoms of inadequate lighting for Purple Milkweed?
Inadequate lighting can lead to several symptoms in Purple Milkweed, including smaller new leaves, leggy or sparse growth, faster leaf drop, slowed or halted growth, paler or irregularly colored new leaves, chlorosis (yellowing of leaves), sunscald damage to leaves or stems, leaf curling, wilting, and leaf scorching with brown, dry edges. These symptoms indicate either a lack of sufficient light or too much direct sunlight.
What are the important symptoms and solutions for Purple Milkweed in low temperatures?
Purple Milkweed is cold-tolerant, doing best when the temperature remains above 0°C and should ideally be kept above -30°C during winter. If temperatures fall below -35°C, the plant may not show immediate changes but could exhibit decreased sprouting or fail to sprout at all in spring. In such cases, removing parts that have failed to sprout in the spring is the recommended solution.
