Where is Covent Garden?

Hint 1 of 8:

Have you looked around Sarah's dressing room?

Hint 2 of 8:

I'm sure you've been dying to find out who her secret admirer is.

Hint 3 of 8:

Maybe the person who sold him/her those flowers could tell you.

Hint 4 of 8:

Do you think the flowers might be the least bit unusual?

Hint 5 of 8:

Take one and find out.

Hint 6 of 8:

Maybe you should look at it a bit more closely.

Hint 7 of 8:

Try using it on your lab table.

Hint 8 of 8:

You'll find out enough about the flower to track it down.  Or you can get
someone else to track it down for you.