Do plants have DNA?

Yes.

Yes. They have the same building blocks we do: ACGT.

DNA molecule: adenine (A), cytosine©, guanine (G), and thymine (T).

All living things flora and fauna.

Yes. Every living organism on the planet does.

… except the space aliens.

How DNA differs is, of course, big business.

All living things have DNA or RNA.

DNA is life!

Yes.

Of course.

You know, this reminds me of the time where a teacher tried to convince me that trees are not plants.

Yes plants have DNA which is as unique to each plant as our DNA is to each person.