Parsley is a good companion to carrots, onions, tomatoes, asparagus and roses. It attracts beneficial insects and acts as repellent to damaging ones. If parsley over winters in your area, let a few plants go to bloom in its second year. Parsley’s flowers are also very beneficial for the same reason: attracting parasitic wasps and hoverflies.
Another easy way to grow parsley is to buy seedlings from the nursery. Choose small plants and disturb the roots as little as possible since parsley is not very fond of transplanting. Choose curly leaf or flat leaf kind, depending on what purpose you’re using your parsley plants for.