In header – show tagline only (not site title)

I’m using a custom image in my header, but then I’d also like to display the site’s tagline alongside it.

Currently, the only way to get the tagline into the banner seems to be to select ‘show header text’ in the appearance settings, but that also puts the site title. My custom header image is the site name as a graphic, so I don’t need the site title again.

Anyone know a way to have only the tagline display?

Thanks in advance