8 Types of Milkweed in California (AND One to Avoid!)
“What types of milkweed should I plant in my garden?”
This may seem like a crazy question if you’re just getting started with native gardening. Why would you want to plant a weed?!
But milkweed isn’t a weed at all. Instead, it’s a flowering plant that attracts butterflies (think Monarchs), native bees, and other pollinating insects, which is an excellent thing!
This article will give you information about common types of milkweed in your area and which ones will be best for your garden. And, keep reading to the end to learn about a kind of milkweed you want to avoid!
8 Types of Milkweed in California:
#1. Desert Milkweed
- Asclepias erosa
Growing Information:
- USDA Hardiness Zone: 4-11
- Life Cycle: Perennial
- Approximate Mature Size: 1.5 to 4 feet
- Bloom Time: May to July
As the name suggests, this species is commonly found in desert regions. Desert Milkweed often grows on dry slopes and washes. The stems are yellow to green and broader at the base.
Identifying this species can be difficult as there’s some variation in the leaves. They grow in pairs on the stem and may be completely smooth or densely covered in cream-colored hair. They’re generally dull grayish or pale to dark green. Desert Milkweed blooms from May to July, forming rounded umbels or clusters of about 20 small flowers atop the stems. The flowers are white, cream, or yellow.
Desert Milkweed is quite adaptable and can be grown from seed in many home gardens. It needs well-drained sandy soils in areas with low organic matter. It should be planted in full sun. Like other milkweeds, its large taproot gives it excellent drought tolerance.
This species is a host plant for the Monarch Butterfly, Queen Butterfly, Clio Tiger Moth, and Euchaetes Zella Moth. The blooms also attract a variety of pollinators, including native bees.
#2. Showy Milkweed
- Asclepias speciosa
Growing Information:
- USDA Hardiness Zone: 3-8
- Life Cycle: Perennial
- Approximate Mature Size: 1.5 to 3 feet; occasionally up to 6 feet
- Bloom Time: May to September
As the name suggests, Showy Milkweed features flashy pink and white umbels or clusters of small flowers. The flowers are fragrant, and individual flowers look a bit like crowns. In ideal conditions, Showy Milkweed may grow as tall as 6 feet!
As a garden plant, Showy Milkweed has the benefit of being a less aggressive spreader than most other milkweed varieties in California. It can be grown easily from seed or the cuttings of an existing plant. It’s very drought tolerant and can be grown in a wide range of soils.
Like other milkweeds, Showy Milkweed attracts native insects and Monarch Butterflies to your yard or garden. Monarchs will visit the flowers for nectar and lay eggs on the plants, which are host plants for the Monarch caterpillars. It will also attract beautiful Queen and Viceroy butterflies to your property!
RELATED: 29 Rabbit Resistant Plants to grow in California!
#3. Antelope Horns
- Asclepias asperula
Growing Information:
- USDA Hardiness Zone: 5-9
- Life Cycle: Perennial
- Approximate Mature Size: 1 to 2 feet
- Bloom Time: March to October
Antelope Horns, also known as spider flower, tends to sprawl toward the ground instead of standing upright. The stems of this milkweed are green-tinged with maroon and densely covered in tiny hairs.
This milkweed species gets its name from its relatively distinctive seed pods. The curved, upturned pods are thought to resemble antelope horns. When viewed from a distance, these plants resemble a field of antelope. The leaves are narrow, up to 8 inches long, and fold inward along the middle vein. Look for the whitish-green or purple flower clusters during its long blooming season.
Like other milkweeds, Antelope Horns’ flowers attract a variety of pollinators. Large native bee species regularly visit the blooms. The plants are also hosts for Monarch, Soldier, and Queen butterfly caterpillars.
This species is relatively easy to grow from seed. Antelope Horns need full sun to thrive and prefer sandy or rocky soil with little organic matter. It’s a great low-maintenance choice, and it thrives without any fertilization and little watering due to its large taproot.
#4. Narrowleaf Milkweed
- Asclepias fascicularis
Growing Information:
- USDA Hardiness Zone: 6-10
- Life Cycle: Perennial
- Approximate Mature Size: 1 to 3 feet
- Bloom Time: June to September
Narrowleaf Milkweed, sometimes called Mexican Whorled Milkweed in California, is often seen growing in large groups. It has a much more delicate, grass-like appearance than Common Milkweed.
It’s most conspicuous when it’s in bloom, from June through September. The blooms are upright clusters of about 20 small flowers. The flowers are variable in color, from greenish to pink, white, and even purple. The thin, spiky leaves are arranged in a spiral around the stem. Beginning in July, seed pods replace the blooms. The seed pods are narrow, thin, smooth, and long. They split down the side and release wind-borne light brown seeds and coma when mature.
In the wild, Narrowleaf Milkweed is typically found in the dry climates of plains, foothills, valleys, and roadsides. In the garden, it can be started from seed and is a great low-maintenance plant. It thrives in areas with full sun and is drought-tolerant.
This species is a host plant for the caterpillars of Monarch and Queen Butterflies and Isabella Tiger, Clio Tiger, Hitched Arches, and Euchaetes Zella moths Various other pollinators like bumblebees and wasps also visit the plant’s blooms.
#5. California Milkweed
- Asclepias californica
Growing Information:
- USDA Hardiness Zone: 7-10
- Life Cycle: Perennial
- Approximate Mature Size: 1.5 to 3 feet
- Bloom Time: April to July
The California Milkweed is a perennial herb with a unique, wooly appearance. The dull grayish-green stems and leaves are thickly covered in white hairs.
The blooms of this species are pendulous, drooping clusters of about ten small pink or lavender flowers. The wool-like hair found on the stems and leaves is present everywhere but the flower head.
In the wild, California Milkweed grows on dry slopes, canyons, chaparral, or woodland foothills. It does well in hot, dry conditions. California Milkweed should be grown in full sun because it doesn’t tolerate even partial shade. Due to its large taproot, it’s extremely drought tolerant once established and thrives in a wide range of soils, including sand and clay. It does best in well-drained soil.
If you’re looking for a plant that will tolerate hot, dry weather and attract pollinators, California Milkweed might be perfect! Its flowers attract a variety of bee and butterfly species. California Milkweed is also a host plant for Monarch Butterfly, Queen Butterfly, and Clio Tiger Moth caterpillars.
#6. Rush Milkweed
- Asclepias subulata
Also called Desert Milkweed.
Rush Milkweed is a unique species that grows many stalks from a single root crown and appears naked for most of the growing season! Like many desert perennials, Rush Milkweed only grows leaves after rain.
Thankfully, Rush Milkweed doesn’t need leaves to obtain energy. This horsetail-looking perennial can photosynthesize using the greenish-white tissue that covers its stems.
Amazingly, these plants can produce flowers and seeds with or without rainfall. Small clusters of about ten distinctive creamy white or yellow flowers form atop the bare stems. The flowers’ corollas are folded back to expose five tiny column-like structures with little hooks at the top.
#7. Heart-leaf Milkweed
- Asclepias cordifolia
As the name suggests, Heart-leaf Milkweed has large, heart-shaped leaves. The leaves are oppositely arranged and usually bluish-green in color. Like other milkweeds, splitting a leaf or stem will release a milky white sap.
Sometimes, you may hear Heart-leaf Milkweed called “Purple Milkweed.” This fitting name refers to the several clusters of dark red or purple flowers that form on two-year-old plants.
Native Americans managed and harvested this milkweed for its fiber to make rope and clothing. Archeologists found a 40-foot-long deer made from about 7,000 feet of Heart-leaf Milkweed that would have required harvesting over 35,000 plants!
Today, you can find Heart-leaf Milkweed growing in California in dry, rocky areas in deserts, plains, woodlands, chaparral, and evergreen forests. It will grow in the mountains up to about 6,560 feet.
#8. Woollypod Milkweed
- Asclepias eriocarpa
Woolypod Milkweed is one of the most poisonous milkweed species in California!
This may not sound like a good thing, but it’s excellent for Monarchs and other specially adapted butterflies that use the toxins in the plants to ward off predators and parasites.
This erect perennial flowers from late spring to mid-fall. The flowers form in large, elaborate clusters near the top of the plant. The clusters are comprised of many pink, white, or cream-colored flowers.
True to its name, the flowers give way to large seed pods, which have a thick covering of woolly hairs. These seed pods split at maturity to release seeds that will be carried away on the wind thanks to their silky pappus, a parachute-like attachment.
Woollypod Milkweed thrives in full to partial shade in dry or well-drained soils. It’s quite drought tolerant, and you may spot it growing in open woodlands, rocky hillsides, deserts, and other dry areas.
Tropical Milkweed
- Asclepias curassavica
Growing Information:
- USDA Hardiness Zone: 8-11
- Life Cycle: Perennial
- Approximate Mature Size: 3 to 4 feet
- Bloom Time: March to November in temperate climates, year-round in tropical climates.
This non-native milkweed plant has become popular in recent years because of its flowers’ bright red coloring and how easy it is to plant and maintain.
Unfortunately, Tropical Milkweed planted in California may do more harm than good.
It carries a parasite of Monarch Butterflies called Ophryocystis elektroscirrha, or OE, which can cause defects in the wings of Monarchs. Since it doesn’t die back and can bloom late, the plant itself may also confuse Monarchs by signaling a breeding season when it’s time to migrate.
To ensure you’re planting milkweed that will help your local ecosystem and attract native pollinators, always choose a native species!
Marketers of Tropical Milkweed seeds will use the names Mexican Milkweed, Bloodflower, Mexican Butterfly Weed, Mexican Orange Milkweed, and Semi-Tropical Milkweed. Steer clear of all of these!
Are you looking for more information on milkweed in California?
Check out this guide!
Do you have milkweed in your garden?
What’s your favorite thing about this plant? Leave a comment below!
