DataGridViewCell style lost on column sort

I have applied a style to a DataGridViewCell to an unbound grid using the
following code. When I click on a column header, the bound data is sorted
but the styles in the non-bound cells are lost. Thanks in advance for any
help!

DataGridViewCellStyle styleTemplate = this.grdPlants.Rows[0].Cells[0].Style;
DataGridViewCellStyle redStyle = new DataGridViewCellStyle(styleTemplate);
redStyle.BackColor = Color.Red;

DataGridViewCell cell = this.grdLocations.Rows[0].Cells[0];
cell.Style = redStyle;