Early in the film, Shakespeare is seen in his garden with Verbena bonariensis (Purpletop Vervain). This species from south America was first introduced to Britain in 1737.
When talking to the Earl of Southampton, Shakespeare repeatedly addresses him as "Your Grace". When addressing an Earl, the correct form is "My Lord" (only a duke, archbishop or monarch would be addressed as Your Grace). The real William Shakespeare spent enough time around nobility to be well aware of the correct title to use.