Rush Milkweed Seeds - (Asclepias subulata)

Rush Milkweed (Asclepias subulata) – A Desert Oasis for Monarchs

Rush Milkweed, also known as Desert milkweed or Cane Milkweed, is a captivating and resilient perennial that stands as a beacon of life in its native arid landscapes of the Southwestern United States and northern Mexico. Its unique appearance is immediately intriguing – tall, slender, nearly leafless stems grow upwards, resembling delicate reeds or rushes, creating a vertical element of visual interest in the garden. These evergreen stems remain vibrant throughout the year, adding a touch of elegance even in the depths of winter.

When spring arrives, these stems seemingly explode with delicate, creamy white flower clusters until fall. Each bloom is a miniature work of art featuring intricate details and a sweet, subtle fragrance. More than just beautiful ornaments, these flowers are a lifeline for a diverse array of pollinators. Rush Milkweed is especially beloved by Monarch butterflies, serving as a nectar source for adults and a vital host plant for their caterpillars. But its appeal doesn't stop there; it also attracts Queen butterflies, native bees, and other beneficial insects like ladybugs, lacewings, and even hummingbirds, making it a bustling cornerstone of a healthy and vibrant garden ecosystem.

This desert dweller is remarkably adapted to thrive in harsh conditions. Its leafless stems help it conserve water, making it exceptionally drought-tolerant and well-suited for arid climates. It flourishes in full sun and requires minimal watering once established, making it a sustainable choice for water-wise gardens. Thanks to its resilience and adaptability, it tolerates poor, sandy soils.

With its upright, shrubby growth habit, it can reach a mature size of 2-4 feet tall and wide. It provides a substantial source of nectar and habitat for the creatures that rely on it, making it a prized addition to xeriscapes, pollinator gardens, and any landscape seeking to attract and support essential wildlife.

By growing Rush Milkweed in your garden, you are adding beauty to your space, supporting pollinators, and embracing the landscape's natural beauty.

Will These Grow in My Area?

While hand-grown in Arizona, these milkweed varieties naturally thrive across much of the Southwest and beyond. Their range isn't strictly limited to the areas shown on the USDA map. If you provide the right conditions, these resilient milkweeds can flourish in your garden, too. Please refer to the map for their typical range and consider your local climate when choosing the best variety for your needs.

If you find a state on the USDA map with areas with climates and conditions similar to yours, then that milkweed variety will most likely do very well in your garden. Don't be discouraged if your location isn't highlighted; focus on finding regions with comparable temperatures, rainfall patterns, and soil types. This will increase your chances of successfully cultivating these beautiful and beneficial plants, regardless of where you live.

Remember, nature often surprises us with its resilience, so don't hesitate to experiment and observe how different varieties perform in your unique environment. 

• USDA Map for Rush Milkweed

Planting and Growing Tips

Milkweed has an intriguing way of guaranteeing its survival. In the autumn, when the seed pod ripens and bursts open, the seeds are dispersed by the wind. Each seed has a natural coating that prevents it from germinating. This protective layer ensures the seeds will not sprout prematurely during the colder months, when they might not survive the frost and harsh weather conditions. 

During winter, moisture and soil gradually wear away the protective layer of seeds. When spring comes, and the temperature increases, the seeds can absorb moisture and start the germination process. This natural timing ensures that the seedlings emerge when the environmental conditions are most suitable for growth and survival.

You can plant Rush Milkweed seeds in spring and fall, whichever suits your needs better. 

Two methods for planting these seeds are cold stratification and direct sowing. The approach you choose should depend on when you want to plant and your garden's climate. First, we'll guide you through the cold stratification process. Then, we'll discuss the advantages and disadvantages of both methods.

Cold stratification imitates winter conditions to jumpstart germination, and it can be done easily at home!

First, label a sandwich-sized ziplock bag with the name of the milkweed and the date. Fill the bag about 3/4 full with sand, decomposed granite, or another abrasive material. Then, add enough water to moisten the sand thoroughly – you should see a sheen of water when you gently squish the bag.

To start, put your seeds into the mixture. Make sure to stratify only as many seeds as you plan to plant, and add only one variety of seeds to each bag. After that, seal the bag and put it on the top shelf of your refrigerator. You should move it a couple of times daily to imitate the natural winter conditions that trigger the germination process, which is aided by the cool, wet, and abrasive environment.

After approximately one month of cold stratification, your seeds will be ready to plant. Follow the usual planting instructions and watch your seeds sprout into healthy, vibrant plants.

Pros and Cons of Each Approach

Both cold stratification and direct sowing are viable methods for planting Rush Milkweed seeds, each with its own advantages and drawbacks.

Cold Stratification 

Pros:

Improved Germination – Cold stratification significantly increases germination rates by mimicking the natural winter conditions that trigger the seed to sprout. This process breaks down the seed's natural dormancy, leading to a higher percentage of successful germination and a more uniform emergence of seedlings.
Earlier Emergence – Seeds that have been cold-stratified tend to germinate sooner in the spring than those sown directly outdoors. This head start gives seedlings more time to establish themselves and grow before the heat of summer arrives.
Controlled Environment – Cold stratification occurs indoors, typically in a refrigerator, providing a protected environment for the seeds. This shields them from pests, diseases, and unpredictable weather conditions that could otherwise hinder germination.

Cons:

Requires Preparation – Cold stratification requires some planning and preparation before planting. This involves gathering materials like sand or vermiculite, moistening them, and placing the seeds in a sealed container or bag for the designated period (usually around 4-6 weeks for Rush Milkweed). Additionally, you'll need to monitor moisture levels and ensure the seeds don't dry out. 

Direct Sowing

Pros:

Simplicity – Direct sowing is a straightforward method involving planting seeds directly into the ground without pre-treatment. It eliminates the need for extra steps like cold stratification, making it a convenient option for those who prefer a simpler approach.
Natural Process – By planting seeds directly outdoors, you allow them to germinate naturally in their intended environment. This can result in stronger, more resilient seedlings that are adapted to your garden's specific conditions.
Large Scale – Direct sowing is ideal for planting large quantities of seeds, such as when establishing a wildflower meadow or creating a large milkweed patch for Monarch butterflies.

Cons:

Lower Germination – Germination rates for direct-sown seeds are typically lower than those that have been cold stratified. This is because the seeds may not experience the optimal conditions for breaking dormancy and initiating sprouting.
Vulnerability to Pests – Seeds sown directly into the soil are exposed to various pests, including birds, rodents, and insects. These creatures may eat the seeds or damage young seedlings before they have a chance to establish themselves.
Unpredictable Weather – Unfavorable weather conditions, such as extreme temperatures, heavy rains, or drought, can negatively impact germination and seedling survival. 

Space individual plants 1-2 feet apart to allow for adequate airflow and growth. Sow seeds directly on the soil surface, then lightly cover them with a thin layer of sand or soil, taking care not to bury them too deeply. Depending on temperature and moisture levels, Germination may take 1-4 weeks. Be patient, as milkweed seeds are known for their sometimes slow sprouting.

Once your Rush Milkweed has sprouted, water new seedlings regularly, keeping the soil moist but not overly wet. As the plants mature, they become remarkably drought-tolerant and will thrive with deep, infrequent watering. Allow the soil to dry out between waterings to mimic their natural desert environment. Fertilization is typically unnecessary, as Rush Milkweed is adapted to nutrient-poor soils. However, if desired, a light application of balanced fertilizer in spring can promote more robust growth. Pruning is not required, but you can remove spent flower stalks to maintain the plant's appearance and potentially encourage additional blooming. For overgrown plants, cutting them back to the ground in late winter or early spring can stimulate fresh growth.

With its hardy, resilient nature and adaptability, Rush Milkweed is a rewarding and low-maintenance addition to any garden. Following these simple planting and care tips, you can successfully cultivate this beautiful desert plant and provide crucial habitat for Monarch butterflies and other essential pollinators. 

Why This Milkweed is Special

This milkweed seed is of the highest quality available anywhere. It has been meticulously hand-grown across central and northern Arizona and then carefully hand-harvested, hand-cleaned, and hand-packed to ensure its purity. Since 2018, it has been test-grown at different elevations to verify its vigor and adaptability to different conditions. 

Terroir Seeds is honored to be the exclusive partner in offering these exceptional milkweed seeds to home gardeners. The sale of each seed packet supports the research of the Arizona Milkweeds for Monarchs organization, which is a dedicated group of volunteer citizen scientists overseen by professional scientists from Northern Arizona University. 

The milkweed plant, scientifically known as Asclepias spp., is essential to the Monarch butterfly's life cycle. Monarchs travel across the United States every spring, laying eggs on native milkweed plants. These plants are the only source of food for newly hatched monarch caterpillars. Arizona boasts over 40 species of milkweed, which accounts for more than 50% of the total diversity of milkweeds in the continental US. This diversity of milkweeds makes Arizona second only to Texas in terms of its variety of milkweeds. 

Harvest Tip

Collect the seed by letting the pods turn a rosy-tan color so the seed matures before starting to dry. Keep a close eye on the pods as they dry so you know when they start to open. The pods will develop a small split or crack along the seam about a day before they open, so watch for this to happen.

Don’t force the seed pods open, they will start to open when they are ready and the seed is mature.

Once the pod begins to split open, open it fully and strip the seeds from the white “silks”. If you’ve caught the pod at the right time, the seeds can be stripped from the silks right in the pod without having the silks fly all over the place.

The seeds should be brown/black and dry looking. Store in a paper bag to finish drying completely before storing in a cool, dark place.

Learn More

• Milkweed, Monarchs and Home Gardeners to the Rescue
• Milkweed Seed Germination Procedures 
• Growing Milkweed for the Monarch Butterfly
• Planting A Pollinator Feast

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