Julia, 46, and her mother Betty Lou buried Motes' ashes at an intimate memorial service held at the New Smyrna Cemetery on May 3, reported Us Weekly.
Roberts was reportedly "very polite and kind" at the ceremony, which was attended by family and friends of her late sister.
37-year-old Motes was found dead in February. A suicide note was later discovered at the scene.
Prior to her death, Motes posted several tweets that implied herself and Roberts were not on speaking terms, and referred back to her youth when the 'August: Osage County' actress allegedly made fun of her weight.
