It's not classed as an invasive weed here in Florida. Check online for your invasives, as it's different in CA. The birds eat the seeds here, and I honestly have only had it spread by cuttings, and if a stem gets damaged, and touches the ground sometimes it will root itself. Never had seedlings show up.
Here's the contact page for your LA County Extension people.
http://celosangeles.ucanr.edu/... Scroll down the page and under "Environmental Horticulture" they have several people including phone numbers and e-mail addresses. You could contact one or all of them and ask if this plant is an invasive or if it's ok to plant where you are.
