Joanna Kathleen Sizer

Born September 5th, 1944 • Detroit, Michigan; Entered Eternal Life on May 8th, 2026 • Age 81 • following a late-in-life and courageously fought battle with cancer.

Joanna was the eldest child of Charles L. Bagley and Jeanne S. Bagley (Dolphyn). She graduated from Dominican High School in 1962 and began working with the Michigan Bell Telephone Company. She later completed studies at the Detroit Business Institute, specializing in JBM Key Punch,

Shortly after high school, Joanna married and welcomed her three sons in 1964, 1965, and 1966. After a brief period living in Baltimore, she returned to Detroit for several years working for both the S.S. Kresge Corporation and General Motors in their Photographic Division. In the early 1970’s she moved to Colorado with her boys and continued her career with General Motors in the Service Parts Operations Division in Denver.

Raising three boys who were each just one year apart was more than a full-time job, and Joanna excelled at it. She filled their childhood with new experiences, unwavering support, and a deep sense of security. She consistently put her sons’ needs before her own and never hesitated to sacrifice so they could thrive. Her work ethic was unmatched, and she instilled that same drive in her sons. Fearless and determined, Joanna faced every challenge head-on and taught her boys to do the same. Her lessons about life, money, responsibility, and honesty shaped them into the men they are today.

Joanna’s hands were rarely still. She enjoyed detailed genealogy research, needlepoint, counted cross-stitch, scrapbooking, knitting, canning, baking, and a variety of other pursuits. A lifelong gardener, she tended enormous vegetable and flower gardens, spending countless hours “crawling” among her plants with joy and purpose. She loved to travel and cherished time spent visiting relatives and friends in Belgium, Italy, and Germany.

On August 9, 1989, Joanna began a new chapter when she married Malcolm A. Sizer, and together they made their home in Parker, Colorado. In March 1992, she proudly earned her Bachelor’s degree in Business Administration from the University of Denver and was inducted into the Golden Key National Honor Society. Joanna retired from General Motors after 25 years and enthusiastically devoted her time to helping care for her two oldest grandchildren; once again filling young lives with adventure, learning, and love.

Joanna and Malcolm shared 29½ years of marriage until his passing in February 2019 after his own battle with cancer. Joanna continued to live independently in her home until the time of her passing.

She was preceded in death by her parents, Charles L. and Jeanne S. Bagley, and her husband, Malcolm A. Sizer.

She is survived by her sister Deanne Simpson (CJ); her sons Howard C. Heaney II, Shawn P. (Angela) Heaney, and William C. Heaney; her grandchildren Shawn David Heaney, Mark Logan Heaney, Henry Douglas Heaney, and Josephine Rose Heaney, all of Colorado; and her step-grandson Luca Elias Bruggen of Germany.

Joanna will be deeply missed and forever loved