Beginner Gardening: What are these white things on my Mexican Petunia stems?, 1 by SavvyDaze

SavvyDaze wrote:
I have about 8 Mexican Petunias lining the south side of my house. When I was watering them the other day, I noticed the 1 in the middle had what I thought were tiny white bugs covering the lower portions of the stems and on a few lower leaves. None of the other Mexican Petunias had these white things. Thinking they were some pests, I hosed off as many as I could. Anyway, when researching something else the other day, I ran across a photo of these white things on the stem of a plant that looked very much like what was on mine. The photo I found said they were some butterfly eggs.

Can someone take a look at my pictures and see if they can tell what these white things might be? These photos were taken 2 days after I attempted to hose them off. Originally, you could barely even see the lower stem at all. The pictures aren't great, but were the best I could do.