Butterfly Weed vs. Tropical Milkweed

kellybird02(7b)July 7, 2009

Hi there! I am curious what you all think about the attraction of butterfly weed (asclepias tuberosa) vs. tropical milkweed (asclepias curassavica) as a nectar plant in your butterfly garden.

Last year I had a small patch (3 plants) of butterfly weed and these attracted many nectaring butterflies and later in the summer I had some monarch cats on them which I brought indoors to raise.

This summer I got an early start after reading that tropical milkweed is more attractive to monarchs and I got a bed of about 20+ plants of tropical milkweed out and it is doing great. My little bed of butterfly weed came back big and full but still much smaller than my new patch of tropical milkweed, yet it (and my lantana, as a side note) is FAR outweighing the tropical milkweed in popularity as a nectaring source. As for the Monarchs I have not had any yet but if they come by when they did last year, they will not show up til later in the summer.

My question is actually two fold. First of all, am I right in thinking that tropical milkweed is more attractive to monarchs for laying eggs? And secondly, which milkweed is the best for nectaring - because many butterflies are listed as being attracted to milkweed - so which type of milkweed attracts the most butterflies??

Thanks so much for sharing your experiences and opinions!

Kelly :)

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In the early spring when the monarchs come through St. Louis, they use both incarnata and tuberosa. What they are looking for is young new growth. If it's old and tough, they try to find other plants.

Later when the annual currasavica milkweed is planted and it has the new growth, they move over to it.

All three are good host plants. Here's a picture of their eggs on incarnata in the early spring when the plants are just poking up.

    Bookmark   July 8, 2009 at 7:29AM
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Hello. This is an interesting post to me. I have been raising Monarchs for several years. I sort of "gave up" on the tuberosa quite a while ago. It didn't thrive in my garden (ending up dying) so I have focused on the tropical milkweed and swamp milkweed. The tropical has always been the favorite of Monarchs in my garden, but as mentioned above (great photo!) the incarnata is also popular. Maybe I should try the tuberosa again. I always focus on the "host plant" part of milkweed, although I know that the flowers are a favorite nectar source for butterflies. I think the tuberosa blooms earlier....I have seen it blooming here in Minnesota now and my incarnata has not started blooming.

This has been the worst year for Monarchs. I have hardly seen any Monarchs and had very few eggs and caterpillars in my garden.

    Bookmark   July 8, 2009 at 10:18AM
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I've been growing tuberosa for years and have only found one large caterpillar on it, a few years ago. Never any eggs or smaller cats. I get the most activity on incarnata, and curassavica third. I've only been growing syriaca for a few years and it's more of a thug than a host plant in my garden. It sure does spread far & wide. The only thing I've really noticed on it are ants and some aphids. This is the first year it's ever bloomed for me, and wow, what a fragrance! I'm just starting to find eggs this year (they're very late this year) and they've all been on the incarnata...

    Bookmark   July 8, 2009 at 12:31PM
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jrcagle(z7 MD)

The thing about A. tuberosa is that it is a fantastic nectaring plant for Hairstreaks. Check out the pictures of Hairstreaks in Kaufmann's -- a large number of them are on A. tuberosa.

But as a hostplant, I agree that the incarnata seems to be better.

But along with species, the tenderness of the leaf seems to matter. I've gotten a lot more eggs on young, tender plants than on old, tough ones.


    Bookmark   July 8, 2009 at 3:09PM
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bernergrrl(z5 IL)

I love A. tuberosa, and last year there were some Monarch cats on it but not that much. I grew A. curassavica for the first time, and it seemed to be preferred over incarnata.

I saved some seeds of curassavica, but they didn't germinate for me nor have any volunteer seedlings popped up for me this year. Sigh. I'll have to remember to buy some seeds for next year and start them early again.

    Bookmark   July 8, 2009 at 4:25PM
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Ah, I love it when our personal experiences are re-inforced by the research. There is a lot of research out there that basically backs up what you all are saying. Based on the articles I have read (a lot of which are available from Monarchwatch.com)indicate that A. incarnata (swamp milkweed) is preferred. A. tuberosa (butterfly weed) has very low moisture levels, which does not allow the uptake of nitrogen. This means it takes much longer for the caterpillar to grow. Caterpillars feeding on A. tuberosa need to eat almost twice as many plant calories to equal the same number of A. curassavica (tropical, mexican, bloodflower) or A. incarnata plant calories (does that make sense?). They basically have to eat twice as much of A. tuberosa.

A. syriaca is a good plant because it is so widely available. However, it has huge amounts of latex. Many, many first instar cats are lost to this latex. I think this is much worse on A. syriaca than on some of the thinner leaved milkweeds such as incarnata.

The key to all of this is to keep your plants well fed and watered. There is a direct relation between the health of the plant and the health of the larva.

By the way, I had my first eggs yesterday too! It was on A. incarnata.


    Bookmark   July 8, 2009 at 8:28PM
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bernergrrl(z5 IL)

Cool stuff, Elizabeth! Interesting about the research--makes sense about the tuberosa.

    Bookmark   July 9, 2009 at 6:30AM
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Yes, very interesting Elisabeth. Now I won't feel too guilty when I yank out the syriaca!!!

    Bookmark   July 9, 2009 at 10:08AM
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bernergrrl(z5 IL)

Elizabeth--Would the latex that is found in syriaca also be somewhat present in purpurescens? I ask because the leaves look fairly similar, and I have not found any cats on the Purple Milkweed, although to be fair I only have a couple of small plants.

    Bookmark   July 9, 2009 at 12:42PM
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I am growing a greater amount of Asclepias milkweeds now, and have noticed that nectaring seems to be broken up into the structure of the flowerheads. Plants like Tropical milkweed have small clusters that mostly wasps nectar from.

Swamp milkweed forms a large umbrella shape of blooms that fritillary butterflies seem to favor, and they literally walk around the cluster before moving to the next cluster, which is probably true of Red-ring milkweed if it were a full sun plant.

Butterflyweed has an extended/arm shape row of flowers that I've noticed mostly Black swallowtail and Zebra swallowtail will visit regularly.

My Swan plant bloomed too early in the year to make any observations, and the Poke milkweeds aren't mature enough to bloom -- these have flowers that hang pendulously as individual flowers, including Clasping milkweed, and Four-leaf milkweed.

Hairstreaks don't seem to have that much of a preference of the milkweeds I have in bloom. Duskywings and skippers I've seen on all types of milkweeds without preference.

I'm interested to see when the Oval-leaf milkweed blooms to see what it attracts the most. It is a small species that has a side hanging cluster of blooms like Common milkweed.

As for eggs/caterpillars, I've overwintered my Tropical milkweed and it doesn't get any eggs past it's first year growth. However, now that I know it's water requirements well, I'm going to try letting it dry out, drop it's leaves then get it to flush with new foliage to see if that attracts any eggs. When they were in the first year growth, the Butterflyweed was ignored, but the second year the Butterflyweed got a small share of eggs, even though they were mature. However, the Sand/Blue vine milkweed (Cynanchum laeve) consistently gets 2-3 caterpillars a year, possibly more eggs that don't make it... which I think that might have something to do with the continual new growth as the vine grows throughout the year, provided it is consistently watered.

    Bookmark   July 9, 2009 at 1:47PM
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It's so hot here that I can't seem to keep any Milkweed alive but Tropical! I would love to have a variety but everything else just dies.

    Bookmark   July 9, 2009 at 6:10PM
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bernergrrl(z5 IL)

Gardenspider--You get lots of butterflies! I've never seen a hairstreak nectaring in my yard. And you have quite the collection of aslepias too!

    Bookmark   July 9, 2009 at 6:57PM
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That is an interesting question. Purpurascens is always left out of the literature, as is a lot of the other types. I have been watching it in the prairie and plan to plant it in my garden as well. One of the other strong factors for choice by momma monarch appears to be the levels of cardio glycosides (I hope I have my compounds right). Too high and it is too toxic for first instars and too little does not afford enough protection. In a forced choice situation, mom will take what she can find like Cynanchum laevae, which has no cardiac glycosides. However, a mid-level to moderately high level, which incarnata, syriaca, and curassavica have, fit the bill. I am not sure what purpurascens' levels are like. I have seeds for five different milkweeds and plan on growing them to see what happens here in Ohio. I do love the purpurascens though, so pretty! Ooops, guess what, I just did a little digging. It seems that purpurascens hybridizes with syriaca. What often times is thought of as purpurascens is a hybrid with syriaca type leaves. If you google purpurascens and look at images you will see that the leaves are actually more simillar to a wider incarnata. Yikes! I thought what we had in the prairie was purple but it is a hybrid. Well, I have seeds from prairie moon. Wonder what they sent me.

    Bookmark   July 9, 2009 at 8:05PM
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You might be better off visiting the Arboretums and Botanical gardens because they often offer native species that you can't find at nurseries or hardware stores.
Also, I water my milkweed plants regularly, even though some are considered drought tolerant when established. I have 99% clay in most of my yard and there isn't really anything drought sustaining about it.

Thank you on the complement, I could easily go on and on about milkweeds. I've had many newbie set backs, but I enjoy them enough that I press on.

There are many species that I'm searching for a commercial source or trade source for. Especially if anyone is planning on visiting a Arboretum or Botanical garden soon, I could give you two or three species to keep an eye out for that are specific to your region of the country. I am more than willing to compensate. Or if you want to check your yard.

Hairstreaks are small but some are very small. The species I most frequently see in my yard is smaller than my pinky fingernail, which is the smallest of the hairstreaks in my area. I guess I've been keeping tabs of what I attract to the yard. A few years ago I used the BMNA website to compile a list of local butterflies and started trying to plant host/nectar plants, but I have a long way to go. I've found that zinnias are probably the easiest and most generally attractive nectar plant, though I have a huge list of plants to try.

You might want to get a set of good digital photographs and post the images for others to examine. Common milkweed (Ascleias syriaca) has a broad range of colors for the blooms, and cultivar known as Mona that is rather purplish, but not as bright as (Asclepias purpurascens). Also, common milkweed has tendency to curl the leaves which make them look similar to (Asclepias purpurascens). Not only that but there documented differences within the same species from different regions.
I will provide a hyperlink to a webpage about a naturally occurring cross between Common milkweed (Asclepias syriaca) and Poke milkweed (Asclepias exaltata). Some studies were done to determine that ratio of the hybridization, since the hybrids hybridize with the parent species.

Here is a link that might be useful: hybrid is mentioned lower on the page

    Bookmark   July 9, 2009 at 10:15PM
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bernergrrl(z5 IL)

Elizabeth, I raised my purpurescens from seed from Prairie Moon. I don't have any syriaca in the yard, and I was going to try to put some out in one of my "wild" areas, but I think now I will hold off, although I do love the look of the syriaca--it has grown on me--love those big moppy blooms.

Gardenspider--that is an amazingly small butterfly. I love the little ones--they all too easily are overlooked. I try to get pics of everything that comes into my yard except when I don't have my camera; when that happens, I usually see something I don't recognize, like an elfin. I had a Banded Hairstreak visit once; it just landing on a tree branch that I happened to be standing near, and I just happened to have my camera. Would love to see more.

The weather here has not been too accommodating for the butterflies.

Totally agree about the zinnias, although mine have been ignored so far this year. Last year too, come to think of it. Fascinating info about the milkweed too!

Here are a couple of pics of the pupurescens:

Here are a couple of tuberosa--I just love it!

    Bookmark   July 10, 2009 at 7:21AM
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Your second picture definately looks like unhybridized purpurascens. I would hold off putting it in your wild areas until you check out the status of purpurascens in your area, if you haven't done that yet. It is endangered in some parts of the NE. If that is the case in NH, you might want to find out how state officials feel about planting it. I am never sure. Sometimes plant people get a little weird. I had a discussion with KC about this. How they wanted us to plant only natives but then only state natives, and then only county natives. I was like "do they want us to raid the last remnant prairies to find plants or what?" Anyway, sometimes they get funny about mixing gene pools but I am sure planting it in your own back yard is fine. Not to add another burden on you :)!

You have such a pretty garden. Our horticulturalist used tuberosa with Echinacea angustifolia (narrow leaved coneflower) they bloomed together and were so pretty. It was fun to tease him that angustifolia was not native to Ohio. I am so evil.

    Bookmark   July 10, 2009 at 7:55AM
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I have 2 huge tuberosa, plus about 20 medium sized carravassica plants. I am also growing lots of each of these species from seed, so I have lots of little plants I intend to put into the ground in Fall to bloom next Spring. (The currassica I am planning to bring indoors for Winter.) The first cat I found was on one of my tiny tuberosa seedlings, about 2 inches tall at most! If I would not have found him, he would have starved. What an irresponsible mom. The seedlings are at some distance from the main butterfly garden. I guess she was just near sighted, but the seedlings are well away from all the predators. I suppose that is just a coincidence. I just got some small A incarnata plants yesterday. I am going to pamper them in pots until late Summer/early Fall, when I will plants them in their permanent position.

    Bookmark   July 10, 2009 at 10:06AM
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I don't know so much about all the different milkweeds as many of you here. I live in NW Illinois and we have what we call common milkweed that our monarchs seem to prefer for egg laying. Grows wild in the ditches and pastures (when the farmers let it).
I have some orange butterfly weed (asclepias) that they don't seem to be laying eggs on, but do like to feed on the flowers.
In previous years I found lots of cats on the latter, but not this year. Odd.

    Bookmark   July 10, 2009 at 11:59AM
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> sometimes they get funny about mixing gene pools

As I mentioned earlier, within the same species there are differences by regions. Primarily in attributes such as emergence, length of time before flowering, vigor of growth, tolerance to wet/dry periods, disease/insects. In other words, even though the same species exists in different regions, the plants from a particular region have had mother nature selecting out attributes that make the plants best suited to the environment.

All of this is to say that if you are just wanting a particular species to grow in your garden that you cultivate, and you don't live next door to a protected prairie or wild area, then just get seed/plants from anywhere. However, if you are putting plants in your garden that you don't intend to cultivate and let fend for itself, or are trying to restore a native habitat, then it is best to try to get seed/plant sources from your region.

Here are some quotes from Western Illinois University reports on commercial Common milkweed production studies. "Plot establishment (2001): seed was collected from locations in Wyoming, Nebraska, and Illinois", and "Second year results (2002): with the Illinois population showing the most vigor as evidenced by increased height, resistance to fungal diseases, and number of blooms and pods ... with the Illinois population of common milkweed being the last to mature." Also, "Third year results (2003): The Illinois population surpassed the non-native populations in disease and insect resistance as well as plant height and strength."

Here is a link that might be useful: Common milkweed, alternative crop study.

    Bookmark   July 10, 2009 at 12:44PM
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bernergrrl(z5 IL)

Hi Elizabeth, Thanks for kind comment about the garden. I had no idea pupurescens could be an issue. I don't think anyone checks on anything or gets too crazy about stuff here in NH. You know, "Live free or die" state. :) That motto some people interpret literally in different ways (no taxes, do whatever I want, who cares about other people, the environment, etc.)

What's KC? I can understand how some people can get very ornery about planting natives--I went through a phase like that. Even today, I sometimes feel like I should try to get out there and figure out what's growing, what's supporting, what and maybe try to grow only those things in my yard.

But it's just too demanding and hard to do sometimes. So, I just focus on the butterflies and let my wild areas bring in the native plants (mostly); it's been great to see so many things out there: Lady Slippers, Trilliums, Trailing Arbutus, Closed Gentian, and on. These have been little treasures that amazed me that they would exist in my backyard. We are very fortunate in that regard here.

Back to MW--I'll be sure to save some seed from the 2nd pupurescens even though I think they both came from the same seed packet. And I'll check its status here in NH.

Do the cats get the same protection from eating MW flowers that they do from the leaves?

    Bookmark   July 10, 2009 at 12:52PM
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Hi, everyone,

Lots of interesting info about the various MW's here! And pretty garden photos, too.

I would like to know from some of you more experienced BF gardeners if you have your different MWs planted in distinct groups/patches that are easy for the Monarchs and other nectarers to find, or if yours are planted along with other summer flowering nectar plants in a border (like most of mine are)? And then, do you find you get lots more traffic on your distinct groupings? Although my MWs are planted with other BF favorites, I'm beginning to think the Monarchs are having a hard time finding them.

(I also started one packet of Purple Milkweed from Prairie Moon and germinated about 10 seedlings from it~~after 40 days of cold stratification in the fridge). I am hopeful I can get these to grow somewhere on our property, but I understand they are quite particular about planting out placement?)

Thanks again. f. (in Cincinnati, Ohio, Zone 6a)

Here is a link that might be useful: Monarch Watch MW germination info

    Bookmark   July 11, 2009 at 10:46AM
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jrcagle(z7 MD)

Just as an interesting and not-very-controlled study:

I just brought in 13 D. plexippus eggs today.

4 on A. tuberosa: 3 on unopened flower buds, one on the leaf of an immature plant.

9 on A. incarnata: 4 on leaves of mature plants, 5 on leaves of immature plants.

And when I walked up the hill, momma was back on the incarnata, so I'll probably have more there.

So there does seem to be a preference for incarnata, and also a preference for tender growth, BUT that preference is not so strong as to be exclusive.


    Bookmark   July 11, 2009 at 5:01PM
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BernerGrrl, I will try to answer your questions. My brain is not working to well after two and a half days of intensive butterflying. Jaret Daniels was here. He has written many regional BF guides, is a prof. at UF, Gainesville, and assoc. curator at the McGuire Center in Florida. He was here to help us start a Monitoring program. We took him and his lovely wife around to some of the local hot spots. During these site visits we had some interesting discussions about milkweeds. One thing he mentioned was the use of curassavica in Florida. It is non-native there. Other milkweeds go through senescence during winter I assume in Florida. Since curassavica does not, it is allowing Monarchs to breed during times they would not normally. Allowing disease to become an issue.

On the use of non-local natives. We visited one of my favorite spots near Dayton, Ohio. It is a Marionist Monastary. Here a marionist brother, who is a professor at a local university, worked to restore prairies and wetlands on the property. Dr. Geiger has been working with native plants for over 40 years. We were discussing the milkweed hybrid issue. He said at this point finding "primers", local natives to start restoration stock, was difficult and required the use of genetic testing. It was amazing to see the plants he had there though. Grasses they had grown from cemetery plants from remnant prairies thousands of years old. There is something really special about that. I don't want to burden people with having to grow this or that in their own yard but I don't want to make the scientists and conservationist jobs harder either.

So, let's see, next question. KC is a poster here on these boards. I forget his screen name.

Different parts of the milkweed have different nutrition and cardiolide levels. I don't think the flowers have much in the way of cardiolides but have never read anything to be sure. They do have more sugars and the leaves have more proteins. The interesting thing is different plants have different defense mechanisms. Some store toxins in the roots and can send toxins up to the leaves when the munching begins. Some store toxins as separate chemicals in special cells that mix when munched on, forming a toxic chemical. Some in the sap, such as in the latex of milkweed. Some in special cells in the leaves. Probably other ways as well.

That is probably pretty accurate. I think it's a preference not a requirement (if that is the right word). And when it comes to BFs I think they will always do something dopey. Last year we had so many zebras in the house, the one poor paw paw had eggs on every leaf and twig. It got to the point that I saw one mom lay an egg on a violet leaf below the tree. I think sometimes there are so many competing signals that they make a "best choice" decision. But that is just my "I know just enough to be dangerous" opinion.

Hello, you are near me! Come up and visit sometime. Clusters of plants are always better. The bigger the better. It is not necessary though. I am always amazed at how females have been able to find some of my plants. I have one incarnata and I had one monarch lay on it. They just hatched today in fact. Last year, I had a female pipevine visit my pipevine before I got it planted. The same with my tiny paw paws and a zebra. But, it also depends on what you have near you. The closer you are to attractive sites, the more likely you are to have visits.

Okay, I have blathered on enough. I am fried...

    Bookmark   July 11, 2009 at 9:47PM
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butterflymomok(7a NE OK)

very interesting. i planted the purple and the red ring this year.both are doing well. i have blooms on the red ring. i have found that it takes lots of time to get th mw growing from seed. so far all eggs have been found on tropical, oscar and incarnata. i see the female laying eggs but i am not collecting them. viridis seems to be a good choice in the prairie setting. i raised quite a few cats on this mw when i ran out of the incarnaata and tropical they started out on.

bfmom with broken wings

    Bookmark   July 11, 2009 at 11:15PM
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jrcagle(z7 MD)

As an update: I'm up to 26 eggs and 2 caterpillars.

18 eggs and 2 cats on incarnata.
7 eggs on tuberosa.
1 egg on curassavica. I have three of these that I purchased as annuals to fill in a temporary blank spot in the garden, and sure 'nuff, I got an egg!


    Bookmark   July 12, 2009 at 7:09PM
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I have tuberosa and currassavica. Most of the caterpillars went for the currassavica, and I had always heard this was their favorite food. But yesterday, my neighbor brought me some Common Milkweed leaves he gathered from the woods - oiyks! how big they are!! - and I put them in my my dear little cats, thinking that they would not like them, because they eat only the finest imported milkweed. But as soon as they were aware of its presence, the dove on it and munched like I have never seen them munch before. Overnight, they were eating a whole leaf apiece, or more. And I swear some of them doubled in size over night. I have to get me some of that Common Milkweed because my cats think it is the total yum.

    Bookmark   July 12, 2009 at 8:55PM
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four(9B (near 9a))

Original inquiry about nectar did not receive much direct treatment.

For seven years I have had the latter species.
I can report that :
- every butterfly species here likes it
- its flowering "season" here is all year
- a plant practically never is flowerless after it has become a flowering plant
- flower mass is small (many plants needed)
- when many are flowering, monarchs stay all day every day
- when few are flowering, monarchs visit occasionally

    Bookmark   September 28, 2012 at 7:30PM
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terrene(5b MA)

I agree with posters above that Asclepias tuberosa appears to be an excellent nectar plant. The butterflies, as well as bees and wasps love it. The Monarchs don't use it much as a host plant in my yard though. I've found a couple or three cats on it over the years and this year only one egg on the A. tuberosa. In contrast, found numerous eggs (at least 1-2 dozen at a minimum) on each of the A. syriaca (common), A. curassavica (tropical), and A. variegata (several Monarch mamas loved the small plants of the redring milkweed).

Last year a 3 winged female egg-dumped at least 150 eggs on a nice stand of A. curassavica. They also love A. incarnata, but the slugs knocked mine completely down this year (think it's slugs anyway) and it didn't grow AT ALL, bummer.

I'm trying to grow about a dozen species of Asclepias, with more or less success. Not the easiest genus of plants to grow.

    Bookmark   October 2, 2012 at 12:39PM
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