I have found O saundersoniae easy in large pots or in the ground but I have not left them out for winter as I have noticed they can rot if too wet even before winter, so I assume they would not be winter hardy here in NY. As Fiona says, they are easy from seeds, and they produce plenty of them. Sow warm, the large flat black seeds germinate easily. The whole plant is supposed to be highly poisonous if eaten but deer ate a flower stalk at least once when I had it in my school garden (hope the deer croaked, they are a real problem in may places though they are native, besides damage to gardens they eat the native understory plants, preferring delicacies like orchids and trilliums, and spread at least 4 different diseases due to the Lyme ticks that have surged in abundance along with the deer population boom). Here at our house I grow them in large pots so far, but as my stock increases from seed, I will plant them out in spring and lift in fall for a dry dormancy indoors. Ernie DeMarie Briarcliff Manor NY where we just had some heavy rain, and the Erythrina zeyheri that made it thru the winter with protection continues to enlarge and shows signs of a flower spike forming in a leaf axil. Keeping fingers crossed......