Abarim Publications' online Biblical Greek Dictionary
The verb βλαστανω (blastano) means to bud, sprout or grow. It's derived from the noun βλαστος (blastos), which in the New Testament occurs only as the name Blastus.
Our verb is used in the Bible in the sense of to produce or yield (James 5:18) or to sprout (Matthew 13:26, Mark 4:27, Hebrews 9:4). It lives on in modern English in word such as blastula and blastocyst (and of course, slightly distorted, in the verb to blast).