Marigold is adorable. Now let's work out an equally adorable sibling...
These are some from my own list;
Of these, I think the longer ones with more than two syllables work beautifully. Josephine and Henrietta sound quaintly Victorian when paired with Marigold. Penelope gives the set a very English edge (I should know, I am English). I also think Philippa works marvellously.Of the shorter ones, I would recommend Alice, Iris (not an immediate flower theme but a nice discreet one) and Vera.