1OFHIS,
Good question. Are you then implying that the Garden was destroyed in the flood? Together with the trees of life and of the knowledge of good and evil?
The question that arises is: did Noah kept in the arc each and all seed according to the plant life that was before the flood? If not, where did all the plant life came back into existence after the flood? And if, as someone suggested, the seeds were not saved in the ark but they were floating on the waters and produced the plant life after the flood, wouldn't be reasonable to think that the seeds of the trees of life and of the knowledge of good and evil would have gone through the same process, and multiply again after the flood?