No milkweed plants = no more Monarch butterflies, plain and simple.
Fortunately, many gardeners and butterfly aficionados are stepping up to the plate and planting milkweed in their gardens, whether in the ground or in pots. Much of the historic native milkweed growing ranges have been decimated by building, ranching, and farming, especially in the Midwest.
Besides being host plants for Monarch butterflies, milkweeds are excellent nectar sources for a myriad of other butterfly species, insects, and even hummingbirds.
Besides being host plants for Monarch butterflies, milkweeds are excellent nectar sources for a myriad of other butterfly species, insects, and even hummingbirds.
This list contains both exotic, nonnative milkweed plants and native milkweeds of which I'm familiar, with emphasis on growing in the SoCal area. It is becoming more apparent that planting native, deciduous (dies back to the ground in winter) milkweed is preferable to cultivating exotic perennials. The Container Butterfly Garden is home to both. The eventual goal is to slowly reduce/eliminate the exotics in favor of native species.
Actually, I'm vacillating between keeping and not keeping exotics as of this writing. I'm not averse to keeping the exotics around, as they are pruned back yearly in order to eliminate Oe spore contamination. Informative articles on nonnative milkweeds and Oe here and here.
All species of milkweed are deer and bunny tolerant.
Exotic Milkweeds:
Asclepias curassavica; Tropical, or Mexican Milkweed
Calotropis procera, Sodom's Apple
Gomphocarpus cancellatus, Wild Cotton
Gomphocarpus physocarpus, Hairy Balls
Native Milkweeds:
Asclepias eriocarpa; Indian, or Woolypod Milkweed
Asclepias fascicularis, Narrowleaf Milkweed
Asclepias speciosa, Showy Milkweed
Asclepias tuberosa, Butterfly Weed
Actually, I'm vacillating between keeping and not keeping exotics as of this writing. I'm not averse to keeping the exotics around, as they are pruned back yearly in order to eliminate Oe spore contamination. Informative articles on nonnative milkweeds and Oe here and here.
All species of milkweed are deer and bunny tolerant.
Exotic Milkweeds:
Asclepias curassavica; Tropical, or Mexican Milkweed
Calotropis procera, Sodom's Apple
Gomphocarpus cancellatus, Wild Cotton
Gomphocarpus physocarpus, Hairy Balls
Native Milkweeds:
Asclepias eriocarpa; Indian, or Woolypod Milkweed
Asclepias fascicularis, Narrowleaf Milkweed
Asclepias speciosa, Showy Milkweed
Asclepias tuberosa, Butterfly Weed
Exotic Milkweeds
*Note: Again, if growing exotic milkweeds and they overwinter for you, please consider cutting them back as to not encourage the proliferation of Oe spores. For more information on perennial, exotic milkweeds and how they are potential vectors of Oe, please refer to the article 'Tis the season...
Asclepias curassavica
Characteristics:
Host and Nectar plant.
Deer tolerant.
Perennial.
Water Requirements: Drought tolerant. Average Water Needs; Water regularly; do not over water.
Height: 18-48 in.
Spacing: 18-24 in.
Sun Exposure: Full sun to part shade.
Bloom Color: red-orange, yellow.
Bloom Time: Late spring to late fall.
Foliage: Perennial. Will die to ground in a hard freeze, but will sprout back from roots in spring.
Care Notes: Central and South American native. Possibly the most well known milkweed specie, that is quite beautiful and very easy grow. Prune back hard in early winter to discourage lingering Monarchs and eliminate Oe. If purchasing this plant at a big box store, or large commercial nursery, be aware that there have been problems with suppliers spraying their stock with pesticides prior to shipping. There have been many disappointed people who have watched their Monarch caterpillars die within a few hours of introduction. Word is getting out now, and vendors are beginning to accommodate butterfly fanciers by not spraying before shipping. Check with your local supply. Lowe's is in the process of securing only untreated milkweed plants, grown specifically for butterfly enthusiasts.
Calotropis procera
Characteristics:
Host and Nectar plant.
Deer tolerant.
Perennial.
Water Requirements: Drought tolerant. Average Water Needs; Water regularly; do not over water.
Height:Up to 15 ft.
Spacing: 6-15 ft.
Sun Exposure: Full sun to part shade.
Bloom Color: White/near white, maroon/purple-tipped.
Bloom Time: All year. Blooms repeatedly.
Foliage: Perennial.
Care Notes: Native to Africa and Asia, C. procera can withstand cold down to 30° F. BIG plant eventually, Sodom's Apple is a fairly fast grower that will provide beaucoup amounts of caterpillar food. Needs room, but will take moderate pruning. This is a tough plant that can endure lots of neglect once established.
Asclepias curassavica
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Asclepias curassavica; Tropical Milkweed, Mexican Milkweed
Characteristics:
Host and Nectar plant.
Deer tolerant.
Perennial.
Water Requirements: Drought tolerant. Average Water Needs; Water regularly; do not over water.
Height: 18-48 in.
Spacing: 18-24 in.
Sun Exposure: Full sun to part shade.
Bloom Color: red-orange, yellow.
Bloom Time: Late spring to late fall.
Foliage: Perennial. Will die to ground in a hard freeze, but will sprout back from roots in spring.
Care Notes: Central and South American native. Possibly the most well known milkweed specie, that is quite beautiful and very easy grow. Prune back hard in early winter to discourage lingering Monarchs and eliminate Oe. If purchasing this plant at a big box store, or large commercial nursery, be aware that there have been problems with suppliers spraying their stock with pesticides prior to shipping. There have been many disappointed people who have watched their Monarch caterpillars die within a few hours of introduction. Word is getting out now, and vendors are beginning to accommodate butterfly fanciers by not spraying before shipping. Check with your local supply. Lowe's is in the process of securing only untreated milkweed plants, grown specifically for butterfly enthusiasts.
Calotropis procera
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Calotropis procera, Sodom's Apple
Characteristics:
Host and Nectar plant.
Deer tolerant.
Perennial.
Water Requirements: Drought tolerant. Average Water Needs; Water regularly; do not over water.
Height:Up to 15 ft.
Spacing: 6-15 ft.
Sun Exposure: Full sun to part shade.
Bloom Color: White/near white, maroon/purple-tipped.
Bloom Time: All year. Blooms repeatedly.
Foliage: Perennial.
Care Notes: Native to Africa and Asia, C. procera can withstand cold down to 30° F. BIG plant eventually, Sodom's Apple is a fairly fast grower that will provide beaucoup amounts of caterpillar food. Needs room, but will take moderate pruning. This is a tough plant that can endure lots of neglect once established.
Gomphocarpus cancellatus
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| -Annies Annuals and Perennials |
Gomphocarpus cancellatus, Wild Cotton
Host and Nectar plant.
Deer tolerant.
Perennial. Will die to ground in a hard freeze, but will sprout back from roots in spring.
Water Requirements: Drought tolerant. Average Water Needs; Water regularly; do not over water.
Height: 36-48 in.
Spacing: 36-48 in.
Sun Exposure: Full sun to part shade.
Bloom Color: White/near white, cream/tan.
Bloom Time: Mid spring through early winter. Blooms repeatedly.
Foliage: Perennial. Will die to ground in a hard freeze, but will sprout back from roots in spring.
Care Notes: Hails from South Africa. Very easy and willing to grow. Prune back hard in early winter to discourage lingering Monarchs and eliminate Oe.
Gomphocarpus physocarpus
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Gomphocarpus physocarpus, Hairy Balls (obviously...)
Characteristics:
Host and Nectar plant.
Deer tolerant.
Perennial.
Water Requirements: Drought tolerant. Average Water Needs; Water regularly; do not over water.
Height: 3-6 ft.
Spacing: 3-6 ft.
Sun Exposure: Full sun to part shade.
Bloom Color: White/near white.
Bloom Time: Mid summer/early fall.
Foliage: Perennial.
Care Notes: South African native. Extremely easy to grow, grows fast to produce lots of leaves for hungry caterpillars. Drought tolerant when established, so don't overwater. Fairly frost hardy. You'll pay a hefty price for those seed balls at a florist shop.
Native Milkweeds
There are a surprising number of native North American milkweed species (at least to me) to choose from that will fill the bill for just about anyone living below the 49th parallel. Focus here is primarily on species that would be of interest to Californians; SoCal in particular, and would be relatively easy to purchase seeds or plants.
There are over 2,000 species of milkweed worldwide; 108-110 live in North America, of which 15 native milkweed species call California home. We will concentrate only on a few species. Other native North American species will thrive here, mostly with supplemental watering. By nature, California milkweeds are drought tolerant, therefor making them prime candidates for naturalizing in xeric and fringe areas of gardens. Let them dry out well between waterings, or suffer the Wrath of Khan (they may croak on you).
There has been a lot of debate regarding the pros and cons of growing natives vs. exotics. Personally, I have no problems growing exotics if they are pruned back in winter to discourage Oe spores and any lingering Monarch butterflies that should be migrating to their overwintering grounds. The intent of eventually growing only deciduous natives in the Container Butterfly Garden is a personal goal, and will depend on the success of maintaining healthy plants in containers. That is the challenge: growing native milkweed in containers can be a hard proposition. Many -- if not most -- natives develop long taproots that make growing them in a potted environment very hard. We'll see what happens! If there's not even a modicum of native milkweed success in containers, I will continue to grow exotics and prune them hard for the winter.
Asclepias eriocarpa
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| -Charlotte Masarik. Stagecoach Trail, Laguna Coast Wilderness Park. |
Asclepias eriocarpa; Indian Milkweed, Woolypod Milkweed
Characteristics:
Host and Nectar plant.
Deer tolerant.
Perennial.
Water Requirements: Drought tolerant.
Height: 3-6 ft.
Spacing: 2-4 ft.
Sun Exposure: Full sun.
Bloom Color: White, cream, sometimes tinged with purple.
Bloom Time: May through October.
Foliage: Deciduous.
Care Notes: Pretty much a plant it and forget it milkweed once established, A. eriocarpa grows well in clay soils, in which other natives may struggle in without some coddling. Water once or twice a month is all to keep it looking good and producing those all important leaves. Also called Kotolo, an Indian name given to this plant. Several native American groups harvested Kotolo for its fiber and for medicinal purposes.
Asclepias fascicularis
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Asclepias fascicularis, Narrowleaf Milkweed
Characteristics:
Host and Nectar plant.
Deer tolerant.
Perennial.
Water Requirements: Drought tolerant. Average Water Needs; Water regularly; do not over water.
Height: 2-4 ft.
Spacing: 2-4 ft.
Sun Exposure: Full sun to part shade.
Bloom Color: Pale green, near white, sometimes tinged with purple.
Bloom Time: Early summer through late fall.
Foliage: Deciduous.
Care Notes: Easy to grow; let soil dry out well between waterings. Common at native plant nurseries catering to butterfly gardens. Easy to find seeds and plants online.
Asclepias speciosa
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Asclepias speciosa, Showy Milkweed
Besides A. speciosa, there is the cultivar, A. speciosa 'Davis'. Apparently, 'Davis' is easier to grow than the specie. Annie's Annuals & Perennials lists both for sale on her site.
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| -Annie's Annuals & Perennials |
A. speciosa leaves are grayish-green and bears pinkish blooms. Native to higher elevations than 'Davis'. Very easy to find online, both plants and seeds. If interested in growing this plant, may I suggest sourcing it as close as possible to your garden? A. speciosa is a wide-ranging milkweed, found growing throughout much of the United States. From a genetic point of view, it is wise to plant from sources originating as close as possible to your sites so as not to muddy up the genes of local strains if present, which may have potential adverse effects down the road.
Plants grow and adapt to areas over time, and introducing foreign material may compromise existing local populations by diluting the genetic strengths custom tailored to their regions. This is especially true if one intends to sow seed in local native wildland areas, as some are inclined to do.
A. speciosa 'Davis' is very rare in the trade, including seed. Grayish, fuzzier leaves distinguish this cultivar from the species, plus the flowers tend to be bi colored light pink/dark pink-maroon. 'Davis' is more drought tolerant than A. speciosa. If you know of anyone that grows 'Davis' and is willing to part with some seeds or even plant divisions, by all means, graciously accept. If you don't want them, then please contact me!
Characteristics:
Host and Nectar plant.
Deer tolerant.
Perennial.
Water Requirements: Drought tolerant. Average Water Needs; Water regularly; do not over water.
Height: 2-4 ft.
Spacing: 2-3 ft.
Sun Exposure: Full sun.
Bloom Color: Pink, purple.
Bloom Time: Mid summer through early fall.
Foliage: Deciduous.
Care Notes: Another easy care milkweed, its common name Showy Milkweed is well deserved. A. speciosa sports greener leaves than A. speciosa 'Davis'. Apparently, 'Davis' is a bit more drought tolerant than the species. Both produce lots of fat, wide, fairly thick leaves for caterpillars to munch on. Check with Annie's for more information about their characteristics and their differences. I've yet to find either 'Davis' plants or seeds from any online source other than plants at Annie's.
Asclepias tuberosa
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Asclepias tuberosa, Butterfly Weed
Characteristics:
Host and Nectar plant.
Deer tolerant.
Perennial.
Water Requirements: Drought tolerant. Average Water Needs; Water regularly; do not over water.
Height: 18-36 in.
Spacing: 18-24 in.
Sun Exposure: Full sun to part shade.
Bloom Color: Bright yellow, orange, red/orange.
Bloom Time: Summer through fall.
Foliage: Deciduous.
Care Notes: Some sources list A. tuberosa as native to California, but methinks not. Let dry out a bit between waterings. There are many online offerings, coming in various colors from yellow to reddish orange. Make sure you find the right place for it, as it resents being moved due to the long taproot A. tuberosa produces once established. Nope: you don't wanna mess around with that taproot... but that's what helps make this plant drought tolerant.
I've tried Asclepias incarnata, commonly known as Swamp Milkweed, several times in two separate gardens, but to no avail. In both gardens, they grew very fast early in the season. Towards summer, they attracted hordes of oleander aphids (the yellow ones), eventually succumbing to a slow death. Too bad, as it is widely available online, offers beautiful flowers and lots of leaves. Other regions in the U.S. can grow it much easier than I can. Maybe does better in the ground vs. in pots.
There are many, many, milkweed species to pick from, both native and exotic; this list is but a few. Refer to these somewhat SoCal-centric resources for more information on milkweeds and for their purchase:
References:
Project Milkweed
Monarchs (Danaus plexippus) and milkweeds (Asclepias species)
Monarch Joint Venture: Plant Milkweed for Monarchs
Twelve Native Milkweeds for Monarchs
A Guide to Common Milkweeds of California
California Pollinator Plants: Native Milkweeds
Plants and Seeds:
Milkweed Plant Ideas for North American Butterfly Gardens
California Native Plant Nurseries
Where to Buy Native Plants
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