I thought I'd add this link - Birds Online - Healthy nutrition for budgies - Forage Plants

Birds-online is a favourite of mine & if you haven't been on this site for a while you will see lots of new info for us English speakers. (I had heard that she was working on that for this year.)

Where the above link opens you can see the side bar shows all sorts of plants listed. + she has foods & other health guides marked.

Jac - I get the wheatgrass at the local grocery store ... just check the produce department where they stock the organic stuff. Both my boys like to get some every morning. You can water it every other day and it grows and lasts for a couple of weeks.