It's so nice to see this plant mentioned. I have two plants going on 4 years old. I harvest it for compost tea and have begun using it in salve. For salve, harvest leaves before flowering, chop them up, filling a slow cooker. Cover in extra virgin olive oil and warm on medium for two hours each day. Remember to wipe the condensate off the lid when finished. Mold formation will ruin your product. In 7 days, strain the oil. Use as an oil on skin to heal sunburn, abrasions, etc. or mix with beeswax for a nice healing skin salve. Just remember to not use it on an open cut as it can cause the skin to seal bacteria into the wound causing problems. As for invasiveness, my two plants have not produced any babies. They live in a moist, part sun environment.