Get a magnifier and look for bugs on the undersides.

Looks like normal new growth to me. It takes time for leaves and stems to grow to their mature size. Make sure you don't over water. I learned the hard way that it was why I kept killing geraniums. Allow the soil to dry out completely, and don't be in a hurry to water again.

Thank you both. No bugs or pests but will check again. The leaves and stems and flowers are too small, I have another geranium and it’s not like that. I took a close up picture to get as close as possible but the bigger leaves are the normal ones and the smaller ones are about 1/10. In size. The small stems produce tiny flowers too, the red ones are the bigger ones that were from the normal stems It seems there’s an issue with don’t fully growing. Thanks

I’ll see if things get better in a week or so (the other geranium puts out tall new flowers several times a week). But seems “sudden dwarfism” is not an issue with geraniums. :)

It’s now been more than a month and same, tiny leaves and stems but the plant keeps putting them out and flowers. maybe it’s a dwarf variety but it was not when I bought it. as long as it keeps growing and stays green I’m happy. Thanks all!

I have the same type of geraniums. It’s been 2 months and they just won’t grow. They get fertilizer weakly weekly as all my other plants. I have them in full sun. I just gave up on thinking they are going to get taller or fuller. I swear it is always the ones I buy from the big box store. I could not go any farther this year to get plants. Every year I say I am not going there but they are much closer than any nursery. My friend picked me up a couple for my hanging baskets from a nursery and they look awesome. Live and learn always.

I am having same issue. Stunted growth. Wondering if fungicide might work

First time I noticed it was a year ago. Wonder if they are having seed issues. Or perhaps its the heat. It seems to happen in the hotest part of summer and this year its been hot all summer

I tried a 3 in 1 spray already. I don’t think it’s the heat either. Mine usually love the sun. I just have a some small ones that never grew. I have two containers with all geraniums and some are tall and growing beautiful and some right next to them look like the day I planted them.