A Santa Rosa woman was sentenced Monday to 15 years in prison for last year’s wrong-way, drunken-driving crash on Highway 101 in Marin County that killed a Santa Rosa nursery owner.

Kristine Collier, 48, was already on probation for driving under the influence when she drove south onto the northbound freeway lane Aug. 19 near San Antonio Road and hit Sachiko Umehara, 63, who was driving home from San Mateo.

Umehara, who along with her husband Mike owned Momiji Nursery, which specializes in Japanese maples, died at Marin General Hospital.

Collier, a wine saleswoman with two prior drunken-driving arrests, was charged with second-degree murder.

In May, she accepted a plea bargain in which she admitted to the lesser charge of gross vehicular manslaughter while intoxicated and four other counts in exchange for waiving her trial rights.

Marin County Superior Court Judge James T. Chou handed down the punishment before a crowd of onlookers.

Christina Umehara, the victim’s daughter, criticized the deal, saying Collier deserved a longer sentence. Under state law, anyone convicted of drunken-driving who later kills someone while driving under the influence can be charged with murder.

A spokesman for the Marin County District Attorney’s Office said the plea bargain and sentence were appropriate.

Sachiko Umehara was described as active in the community.

She attended City Council meetings and organized a neighborhood drive to stop a liquor store from getting a permit because it was too close to a school, her daughter said.

You can reach Staff Writer Paul Payne at 707-568-5312 or paul.payne@pressdemocrat.com. On Twitter @ppayne.