I have been growing California Pipevine for more than ten years. It is now well established and takes care of itself for the most part. But I had a few false starts. It does need some attention for the first few years, especially because it is slow to get going. Have you heard the saying, "first year it sleeps, second year it creeps, and third year it leaps"? Yes, it needs to be monitored until it gets going.
Where should it be planted? The roots like lots of shade. So the first one I planted I put into complete shade. It died after a couple of years. I think it is better to plant it someplace where it gets dappled shade or half a day of sun, and then mulch the roots. I don't like mulch much because it reduces habitat for ground-nesting bees, but it can be useful in certain circumstances, such as when Aristolochia roots need to be kept cool.
Another thought when planting is to plan for something for it to climb into. One of mine grows on deck and staircase balusters. A trellis can work. They really seem to love growing up through another bush or tree. My plant that is growing into the Rhododendron seems especially happy. The Rhodie gives the roots heavy shade and the leaves dappled shade. Perfect!
I have seen it growing nicely on the ground at the UC Botanical Garden. The problem with this is, like some other vines, it doesn't flower or fruit unless it is growing vertically. And then it is really boring!
It needs water. After all, it is riparian, which means it normally grows near a source of water. If there is no natural source of water, it will need to be watered for at least the first year. Planting it near a lawn or other plants that get regular water is a good idea.
Then, it needs protection. It is toxic and deer resistant, so deer are not too much of a problem. But but since it is so slow, it can be overtaken by weeds. Again, mulch can help. But hand weeding may also be necessary.
This plant has associations with at least three insects. The Pipevine Swallowtail larvae and adult are pictured here. This caterpillar feeds on the leaves. And the adult only lays eggs on Aristolochia. It definitely uses other plants in this genus, but in California, the California Pipevine was the only hostplant until non-native Aristolochias were imported.
The weird maroon and green flowers are pollinated by a fungus gnat. Seems like they have their needs, too. As you might guess, fungus gnats like dark moist places, and flowers that get too much sun are sometimes not pollinated.
The third insect is a wasp that steals the seeds when the fruits open. I guess they eat them. The wasps love the seeds so much that they are there the second the fruits open and will take every last one. I bag the fruits in June so that the wasps can't get to them and I can have seeds to plant. But I suspect that the wasps are effective propagators as well. Aristolochia weeds show up in random places in the UC Botanical Garden. I am convinced that the wasps drop the seeds and they sprout where they land. So, if you want Aristolochia to grow in your neighbors yards, leave some seeds for the wasps.
Keep in mind that if you want the butterflies, just one plant in your backyard isn't going to be enough. So rogue plants growing from seeds distributed by friendly wasps into neighbors' backyards may be a charming answer to how to grow enough hostplants to create habitat.
