Grow?
How often are plants submerged under floods from creeks and rivers and survive?
I’d be satisfied that many plants would simply survive the flood and continue to live on.
Certainly there would be a short period where there is little to no new growth. The world covered in water brings with it a great deal of mud. Much of what was once on the face of the earth was buried under massively thick layers of mud. The point is that there were very few resources in the area and it makes practical sense that the ark was used for other purposes after the waters receded. Why would they keep it in tact? To what end?