Clarkia are very easily grown by sowing seed .
They are annual and don't spread .
They are short and the pom poms small and regularly spaced along the stem. They can be different colours .
Godetia are annual , low growing and sometimes known as poor man's orchids and are a favourite of mine . They look very different from Clarkia . They grow easily from seed,but don't spread.
I've grown both .
I grow Valerian - they've just gone over .
They have big pom poms -either pink or red ,are tall and fall over if not staked in a flower bed. They love growing in cracked paving as well .They self seed .
Himalayan Balsam is very bushy and the flowers are almost lilac, but not pom pom shaped . I think that it's on the banned list as they are so invasive . I've seen great banks of them growing alongside the River Calder .
I've grown some pinky coloured Alliums which have little pom poms .
Hard to say without a photograph .