California Code, Probate Code - PROB § 1208

(a) Except as provided in subdivision (b), if notice is required to be given to a trust or trustee, notice to trust beneficiaries is not required.

(b) Subject to subdivision (c), where the personal representative and the trustee are the same person, or where no trustee has been appointed, notice shall be given to (1) each person to whom income or principal would be required or authorized in the trustee's discretion to be currently distributed if the trust were in effect, or (2) if there are no such persons, to each person who, under the terms of the trust, would be entitled to any distribution if the trust were terminated at the time the notice is required to be given.

(c) Notice to trust beneficiaries is not required under subdivision (b) where the trust has more than one trustee and notice is given to a cotrustee who is not a personal representative.