(of a plant species, such as rhododendron) spreading naturally after having originally been introduced
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
How to use subspontaneous in a sentence
Authors who have seen the species in the East do not hesitate to say that it is subspontaneous.
Many floras of the south of Europe speak of it as a subspontaneous or naturalized species.
Usually they indicate the carob tree, as cultivated and subspontaneous, or nearly wild.