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Swamp Milkweed Vs Common Milkweed [Top 3 Key Points]

Want to enjoy more Monarch butterflies in your garden? But do not know whether to grow Swamp Milkweed vs Common Milkweed. Guess what? I got you covered.

In general, Monarch butterflies prefer Swamp and Common Milkweed over other species. Despite sharing the same family, these two are not the same. They have a distinct appearance and growing habit.

Thus, to understand the battle between Swamp Milkweed vs Common Milkweed, keep reading till the end.

Do Monarchs Prefer Swamp Milkweed Vs Common Milkweed?

Amongst nine species, Monarchs prefer Swamp Milkweed and Common Milkweed more to lay eggs, per a recent study.

But the Monarch butterfly’s choice of Milkweed varies on several factors. For example, the season and the habitat of the Milkweed species greatly affect the choice of Monarch.

Further, the study suggests the height and number of blooms of Milkweed plants do not influence the female Monarch’s preference.

But, you may find Monarchs lurking on Common Milkweed due to their greater availability.

Nevertheless, you can grow these two in your garden in a controlled manner to help butterflies.

Is Common Milkweed The Same As Swamp Milkweed?

No! Common Milkweed is not the same as Swamp Milkweed. However, they belong to the same Asclepias genus and are Milkweed family members.

Here is a table for Common Milkweed vs Swamp Milkweed with brief differences.

FeatureSwamp MilkweedCommon Milkweed
Scientific nameAsclepias incarnataAsclepias syriaca
Common nameSwamp milkweedCommon milkweed
Native rangeNorth AmericaNorth America
HabitatWetlands, meadows, stream banksFields, meadows, roadsides
Height2-3 feet (0.6-0.9 m)3-5 feet (0.9-1.5 m)
Flower colorPink, mauvePinkish-purple
Leaf shapeNarrow, lanceolateBroad, ovate
Leaf arrangementOppositeAlternate
Toxin contentLowerHigher
Monarch preferenceLess preferredPreferred

Now, let us dive deeper with in-depth differences to understand Common Milkweed vs Swamp Milkweed better, shall we?

1. Growth Habit

Common Milkweed has a vigorous growth rate. So, they can easily grow 2-4 feet tall with a spread of 24-30 inches.

Meanwhile, Swamp Milkweed is also fast-growing but not vigorous as Common Milkweed. But they both share an equal average plant height.

On the other hand, Common Milkweed prefers drier fields, and you can find them thriving on roadsides. They can handle a wide range of soil, like dry or sandy soils.

But in contrast, Swamp Milkweed grows well in wetland areas like marshes and stream banks. So, they prefer moist soil and do not suffer even in waterlogged soil.

2. Plant Appearance

Plant appearance is one of the easy ways to tell the difference between the common Milkweed and Swamp Milkweed.

First, the leaf of Common Milkweed has 3-5 inches wide broad green leaves with clear central veins. But Swamp Milkweed leaves are long, thin, and only 1-2 inches wide.

Swamp Milkweed Vs Common Milkweed
Plant appearance is the best way to tell the difference between Swamp and Common Milkweed.

Unlike Common Milkweed, Swamp Milkweed leaves can add purple coloration in the fall.

Secondly, in terms of flowers, Common Milkweed has a small pink or purple flower. They produce flowers in clusters from June to August, each with five petals.

Meanwhile, Swamp flowers are attractive pink and white blooms. They also produce 10-30 flowers in clusters starting from July.

3. Invasiveness

Common Milkweed tops the Vs. Battle with Swamp Milkweed in terms of invasiveness.

That said, both are invasive plants in one another regions where they can spread rapidly.

However, Common Milkweed spreads much faster than Swamp Milkweed. They do so via their rhizomes and seeds.

Meanwhile, Swamp Milkweed does not compete with other plants due to slower spread. So they do not require meticulous control measures to tame their invasive nature.

Editor’s Note

Deadhead Flowers to Prevent Excess Spread!

Even if the Milkweed is very important to butterflies, it can become aggressive. So they can easily outcompete other native plants.

So, deadhead the flowers regularly to avoid seed formation and dispersal. Also, you can manually remove unnecessary growth.

All The Best!