The views of the Seminar on this item can be represented as follows:
The Seminar (which used the name "By Their Fruits" for this cluster), took the various elements of this saying separately. The commentary in [The Five Gospels] (298f) notes that, apart from "the quip about thorns and brambles in v. 44b," most of the sayings in the cluster belong to everyday proverbial wisdom. While Jesus doubtless drew on conventional and traditional materials, his distinctive insights into the sacred depths of everyday life are best observed in the aphorisms and parables that have no parallels.
Gerd Lüdemann [Jesus] (300f) suggests that Luke has adapted a Q parable (found in a more original form in Matt 7:16-18) by intentionally folding into this section other Q material (Matt 12:34b) to fashion a brief integrated saying around this theme.