Plant id and trimming alyssum

Bala

Found this plant in the Garden but not sure what it is. 

Next, can we trim this yellow flowering plant? I think it Alyssum but not sure.


Thanks 

HalleS

The purple flower is a pansy. They self seed all over my garden. 

I think the yellow plant might be an erysimum, aka wallflower. They flower most of the year and can be given a “haircut” once the blooms have died.