Jennet was born in Brooklyn, New York, where she met and married Robert Henderson. Robert Henderson became an important fruit broker in New York, where he represented foreign and domestic packers, including many Riverside citrus shippers.
In 1897, a visit to Riverside ended with the Hendersons purchasing their own 10-acre property. Local designer Robert Gage and a New York architect prepared elaborate plans for a home called Edgemont. The house was built by Donald J. McLeod, the builder who gave Riverside architect G. Stanley Wilson his early training. The 23-room Queen Anne home included towers, cross gables, and a sweeping verandah. The property had its own reservoir, barn, and winding roads and walkways.
Jennet was Edgemont’s mistress and presided over many entertainments. Guests included Dr. Sarah Maloy and Mary E. Darling. The home was also a cultural center where she staged amateur theatricals including “The Highwayman,” with the family filling several roles including Jennet on the piano, son William as musical director, and son Robert L. Henderson as the choral director and male lead. Jennet, Robert, and their four children lived at Edgemont until disaster struck with the freeze of 1913, which destroyed most of the region’s citrus crops. The Hendersons lost Edgemont to foreclosure.