I have seen it reported (in the text here) that it is a combination of Robinson ( P. munsoniana ), myrobalan, and ‘Wickson,’ and a seedling of ‘Wickson.’ On the question of multiple circulating strains, you might contact Rachael Spaeth, garden curator at the Luther Burbank Home and Gardens. I think that she would be interested in your observation and in providing an answer if she can.
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