From the Topics in the Subtropics blog :: March 4, 2020
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So I've gotten a few calls lately about this vine with a big green pod that is growing in lemon trees. What is done with it and how do you get rid of it?
Araujia sericifera, cruel vine, moth plant, bladderflower is an escaped ornamental that has become an invasive weed in California. Yes, a pretty vine brought into the garden – “poor man's stephanotis” - and it's gotten out of the garden into southern California. It's in the hills, in abandoned orchards, on backyard fences and when it gets into a lemon tree, it takes some effort to remove it before the seeds spread to other trees and beyond.
Bladderflower is a perennial vine that is very vigorous where it gets summer water. It is a common weed in citrus groves, where it would enshroud & smother entire trees if not controlled. Stems are tough and ropy, leaves thick and slightly spongy. Sap is milky white, moderately poisonous and causes skin irritation. It flowers Aug-Oct and the seed pods are obvious later in the fall. The flowers have a pleasant fragrance like jasmine. The reason for gardeners planting it. Plus it grows fast in our environment.
So the vine is entrained in the tree canopy so you can't spray an herbicide. To get rid of it, it's important to get down to the base of the tree and cut it out at ground level, removing as much of the root as possible. It still can regenerate, so it will be necessary to monitor the site, removing new growth as it might happen. Be sure to use hand protection because many people are allergic to the sap. Just cutting the vine at its base is sufficient to kill it. Removing the rest of the vine is necessary if there are pods, in order to prevent them going to seed.
The upside of the plant aside from the fragrant flowers is that it is an alternative food source for monarch butterfly caterpillars.
Calfflora shows cruel vine spread mostly along the coast south of San Luis Obispo, but it has the potential to spread thoguhout much of California. Currently, in the US, it is only found in California and Georgia. It is in New Zealand and Australia.
USDA Description of Plant as attachment below: