May . ▁The ▁se eds ▁fall ▁to ▁the ▁soil ▁and ▁remain ▁there ▁until ▁germ ination ▁in ▁September ▁or ▁October . ▁Germ ination ▁doesn ' t ▁occur ▁in ▁the ▁summer ▁months ▁because ▁the ▁se eds ▁are ▁d orm ant ▁and ▁they ▁need ▁about ▁ 3 ▁months ▁to ▁after - ri pen ▁before ▁they ▁can ▁germ inate ▁successfully . ▁Dra ba ▁v erna ▁typically ▁reprodu ces ▁by ▁self - pol lin ation ▁or ▁self ing ▁in ▁mid - ▁to ▁late ▁April ▁when ▁the ▁bud s ▁begin ▁to ▁flower ▁and ▁will ▁dis per se ▁when ▁the ▁se eds ▁are ▁m ature . ▁ ▁Germ ination ▁ ▁Hum id ity ▁In ▁experiments ▁run ▁on ▁Dra ba ▁v erna ▁se eds , ▁tr ends ▁that ▁are ▁important ▁to ▁the ▁germ ination ▁of ▁the ▁se eds ▁have ▁been ▁noted . ▁In ▁the ▁range ▁of ▁ 0 % ▁to ▁ 2 0 % ▁relative ▁hum id ity , ▁the ▁se eds ▁of ▁Dra ba ▁v erna ▁did ▁not ▁after - ri pen , ▁a ▁term ▁used ▁to ▁show ▁m aturing ▁of ▁the ▁se eds ▁before ▁germ ination . ▁However , ▁se eds ▁at ▁this ▁hum id ity ▁did ▁remain ▁vi able . ▁At ▁a ▁higher ▁hum id ity ▁of ▁ 3 0 % ▁to ▁ 4 0 %, ▁there ▁was ▁a ▁small ▁percentage ▁of ▁se eds ▁that ▁after - ri pen ed . ▁At ▁ 5 0 % ▁to ▁ 6 0 % ▁relative ▁hum id ity , ▁there ▁was ▁a ▁high ▁percentage ▁of ▁se eds ▁of ▁the ▁Dra ba