The link doesn't say whether or not pipevine swallowtails have ever actually laid eggs on the this hybrid pipevine. You'll read here why that's important.

There is some confusion as to what A. durior actually is. According to some sources, A. durior is the large-leaved pipevine that's native to the eastern U.S., but others call that one A. macrophylla. Assuming that your hybrid came from the eastern native, it would be possible, but not likely, for a flower bigger than either parent to result. The hybrid between the tropical cry-baby bush/Erythrina crista-galli and coral bean of the southeastern U.S., E. herbacea is Erythrina X bidwillii, said to be larger and more brightly flowered than either parent. Since one parent is A. elegans or A. gigantea, the leaves are likely to be toxic to pipevine swallowtails, since both of these tropicals are toxic, as I recall. There are some tropicals that aren't toxic, but these are. If the leaves have the chemical make-up (or more nearly so) of the eastern U.S. native - assuming that A. durior is actually A. macrophylla - then it may be alright.

Passiflora incarnata is a favorite of gulf fritillaries, but P. coccinea, a red-flowering tropical, is toxic. The hybrid resulting from this cross, P. 'Lady Margaret' is a burgundy flowered hybrid that gulf frits will lay their eggs on, but not usually until their favorites are taken. Lady Margaret is tender and won't return in the spring in my area, so it inherited that lack of cold hardiness over the cold hardy P. incarnata. So does that mean your hybrid isn't hardy? I don't know.

As far as I know nobody on this forum has tried it. We'd all be reluctant to plant an aristolochia that might be toxic to our caterpillars, if the mother butterfly even laid her eggs on it, which they usually won't do on a toxic-to-them vine. Big flowers aren't the primary consideration here, although we like them, too. Gold rim swallowtails of south Florida use the tropical pipevines successfully, so our south Florida 'butterflyers' would be the ones to try out the new hybrid. Of course, this wouldn't really answer the question as to how cold-hardy the new hybrid is, you'd need somebody further north to answer that question. Hopefully, one of the south Florida butterflyers will see this and respond.

Sherry

I am not familiar with this cross. I have durior growing in the garden, as well as several others including tomentosa, clematitis, fimbriata, and serpentaria. I grow strictly for the Pipevine butterflies. Elegans is toxic to Pipevine butterflies, so I'm wondering if this plant might be toxic as well. It's quite a beauty and the flowers are incredible.

For leaf beauty, you can't beat the native A fimbriata with variegated leaves. Your location makes it possible for you to grow many of the exotic Aristolochias that would not survive in my 7a garden.

There is an Aristolochia group on y__hoo that you might find interesting. The members are from around the world and share seeds. There are lots of Aristolochias out there. Also, Georgiavines sells a large variety of Aristolochia vines and seeds. Germination can be tricky.

HTHs,

Sandy

Hi Sherry and Sandy,

Thanks for your comments. I hesitated somewhat posting on this forum as I had read that A. gigantea (and I believe A. elegans) are toxic to some butterfly larvae. However, I assumed that there would be people with considerable experience growing Aristolochias on this forum.

The nature of the toxicity is not clear to me, nor is it clear whether a hybrid would share that problem. Is it even known whether the "toxicity" is due to a poisonous substance or substances, or whether the plants are "poisonous" simply because they lack some molecule(s) necessary for the caterpillars' survival?

Regardless, I assumed that on a forum like this there would be a number of people who started growing Aristolochias for the butterflies, but then fell in love with the genus for the plants themselves. I know that is true of many who grow Passifloras.

I'm not familiar with the debates over the naming of A. durior and A. macrophylla. For some reason I had thought they were synonyms.

I have a friend who used to be involved in vine propagation at UCBG and I'm hoping to get his thoughts as to whether the parent could have been A. gigantea. I'm sure there are cases where the flowers of a hybrid are larger than either parent, but (particularly in the absence of polyploidy) I would expect they are rare. An 8 inch flower (assuming the description is correct) is a pretty dramatic increase in size. The white flecks on the leaves are also highly suspicious. Again, my impression is that those are diagnostic of A. gigantea, and never found in A. durior/macrophylla or A. elegans. The white "flecks" are odd enough that many people think their A. gigantea is diseased the first time they notice them.

My interest is in the ornamental aspect of the plant, as well as its adaptability. I've grown other Aristolochias--A. gigantea, trilobata/macroura, elegans, and fimbriata. I've offered both unrooted and rooted cuttings of A. gigantea for postage in the past, and at the moment I have rooted cuttings of A. trilobata/macroura that I will need to find homes for.

What intrigues me about this particular hybrid is the possibility that it could resemble one of the tropical species in terms of large and dramatic flowers, yet have unusual hardiness. The hardiness is not an issue for me, but it would be for people living in most of the rest of the country. I would guess that there would be people interested in growing such a hybrid outside if it were possible in their climate.

Passiflora incarnata is an example of a plant whose hybrids differ in their hardiness. Passiflora 'Incense' (P. incarnata x cincinnata) is one that is reasonably hardy for many people (typically given as zone 7, I think, sometimes even zone 6). Others are much less hardy. In that case the origin of the P. incarnata parent may be one factor, as strains from more Northern regions are not nearly as hardy as those from the Deep South. The bottom line is that for either P. incarnata hybrids or for Aristolochia durior x elegans, the hardiness of the hybrid can't be easily predicted. It needs to be tested.

But yes, for those whose sole focus is attracting butterflies, the issue of toxicity is probably more important than hardiness.

By the way, I think the Yahoo Aristolochia group has essentially died, with almost no posts in the last year or two.

Here's an example of what I mean by the confusion (at least to me) around A. durior. The A. durior sold at this on-line nursery has big flowers, not a bit like the small flowers my A. macrophylla makes, which are identical to the ones made by A. tomentosa. There are many other nurseries that call their large flowering aristolochias A. durior - this nursery isn't the only one.

Sherry

Here is a link that might be useful: Aristolochia Durior?

And here's a picture of what my A. macrophylla flowers look like, so it's what A. durior flowers SHOULD look like, assuming they're synonymous. People who want their pipevine swallowtail caterpillars to thrive have to be careful to get the correct vines.

Sherry

Here is a link that might be useful: A. Durior

Thanks for the information you included in your last posting. I would be interested in a cutting of the trilobata/macroura. I was very interested in the different species of the Aristolochias when I first started growing tomentosa and macrophylla. I added the serpentaria as it is a native in my area, and has become an endangered species. The clematitis is a native of Hungary, but is hardy and an excellent LFP (larval food plant) for Pipevine Swallowtails. It remains low, readily spreads, and produces many small yellow flowers which readily form seed pods. The seeds are a challenge to germinate as two stratification periods are required, but I have managed to germinate some. There are other species that I have planted, but have not had much luck getting them to survive. I found the Y-hoo group quite by accident, but it's been about 3 or 4 years since I've visited the group. I also have encountered other butterflies in traveling to Asia and Africa that use Aristolochia as a LFP. So that peaked my interest in the vines. There are some very interesting species--and the flowers are intriguing.

I will gladly send postage for your cuttings. Hope you resolve your question about the hardiness. As you mentioned, cultivars of Passiflora incarnata vary in hardiness. Genetic dominance must play an important role. Passifloras are easily identifiable around the world, as are most Asclepias. But, I have yet to identify any Aristolochia plants in my travels.

Sandy

To address your question about toxicity, Mark, I'll copy part of the section about passionflowers in the book Butterfly Gardening for the South by Geyata Ajilvsgi, "Before purchasing a cultivated or exotic plant, inspect the stems carefully and run your fingers along the stems and leaves. If they have rough hairs, do not purchase for butterfly usage. As a protective measure, some tropical species of Passiflora have evolved sharply pointed, recurved hairs which puncture the skin of caterpillars and eventually kill them."

So it may be levels of the toxicity that passiflorae or aristolochiae all have - too much might be toxic - or another chemical altogether, or it might be other characteristics, such as recurved hairs.

Sherry

Do A. Macrophylla seeds need to be soaked and stratified before germination? Does anyone have any seeds for other varieties that would be hardy for my zone?
Thank you,
Pam

Folks,

For the record, durior = macrophylla = sipho. All of these refer to the same species. With that said, there are many photographs on the internet of elegans and tomentosa that are incorrectly labeled as durior. Even Wayside Gardens had to be reprimanded for selling elegans as durior. So when you see a nursery stating it has a cross between elegans and durior, be careful. The photos to me seem to much more strongly suggest that this is a cross between elegans and gigantea and not elegans and durior.