Propagating some Tree peonies

I visited Cricket Hill Gardens last weekend, and came back with some seeds and scions. I have germinated them from seed successfully in the past so it shouldn't be a problem this time around with fresh seeds.

These are supposed to be white Rockii tree peonies.

They are supposed to germinate next spring since they are still yellowish and have their moisture.

Can tree peony seedlings grow more leaves in the summer?

One thing I have always wondered is if tree peony seedlings could gather up enough energy to produce even more leaves, or if what appears in the spring is everything that will appear for the year. Now that it has been nearly 4 months after the tree peony seedlings started to come up, some of them have started to grow more leaves. I think it depends on how good the soil is, the species, and perhaps if there is enough moisture.

Here are some of the ones putting on more leaves. The new summer leaves appear to be slightly larger than the ones appearing in the spring which means the plants have  already gathered some energy.