I think 8" is too small for Moonflowers. Can you get a bigger one?

If you use the 8" pot, only one Moonflower. I guess you can add a couple of MG seed's but the roots from al lthe plants may get too crowded.

Also, in that small a pot you might have to water a couple of times a day.

I already have them planted and they are definitely taking off and established, so I'm not gonna bother trying to move them, I'm just gonna thin them out by cutting them off at the soil so I don't bother the roots. I'll try again next year with bigger pots for sure