The water in the plant would immediately begin to boil (not because of heat, but because of the lack of air pressure in the vacuum of space), probably rupturing the cell walls of most cells I would think.

So to answer your question would probably be: The plant could continue to grow in space for a few fractions of a second.

The pot of petunias are dead on impact

It depends on the plant, moss apparently is pretty hardy. https://www.cell.com/iscience/fulltext/S2589-0042(25)02088-7

I don’t have any real expertise here. But my bet is that it would die pretty much instantly as all the water in its cells boiled off and burst all the cell walls.

Somebody with a vacuum chamber please put a plant in it for science