We had tetrapanax for years in Garden Grove. Don't know if I'd call ot a garden thug, but it will spread past the area it's planted in. The 'fuzz' from the flowers and stems can get in your eyes when handling/trimming the plant, but is not a problem unless you 'disturb' the plant. Nice tall tropical look, with flower spikes that look like schefflera flowers in form, but covered in light grey/yellow-green velvet. As far as Mandelas Gold goes, I grew mine from seed- takes 5-6 years here in north TX to flower. We're not really in S.reginae growing country, if you know what I mean. I see them at independent nurseies in SoCal from time to time, but most mail order places sell only very small starter plants.
Happy hunting!
