I'm pretty sure this used to be true, but I can find nothing definitive on the Internet to confirm it.
The WI these days is trying to get away from its 'Jam and Jerusalem' image and redefine itself as a modern women's movement, "providing women with educational opportunities and the chance to build new skills, to take part in a wide variety of activities and to campaign on issues that matter to them and their communities." Home and Country was the title of the magazine that the organisation published for 85 years, but this was replaced in 2006 by WI Life – which is now sent free of charge to all members.
As for the motto, the closest I could get to confirmation was on Flickr, where someone called Stuart posted a photograph of some WI badges, one of which has these words emblazoned on them. (The other is in Welsh, and presumably has a translated version.) Stuart writes 'The WI motto "For Home and Country" suited [the WI's] aims and was readily adopted in 1915.' Stuart seems to be a badge collector rather than someone with any kind of stake in the Women's Institute.
© Haydn Thompson 2017