Any time I hear the foliage is lovely but I have no flowers Immediately I think ---Too much nitrogen. Nitrogen is the first number on your fertilizer package. Flower fertilizer should be balanced--15-30-15 or 10-10-10 or 20-20-20. Personally I like the time release fertilizer for pots. IT is good for about 4 months and in my growing zone that means the whole summer.

Anything can be grown in a pot. If it were the pot the plant would fail to thrive at all.

I assune since they are in pots they are Peligoram geraniums. These do not require much fussing over. They like to dry out between watering and only need fertilizing about every 3 weeks with a water soluable fertilizer or 1/4 strength every week or as I do with time release.

Cut back on the fertilizer and ignore them a while and you'll get flowers