Display projectile root in spaceline mode line

Question

I use spaceline configured in the following way;

(use-package spaceline
  :ensure t)

(use-package spaceline-config
  :ensure spaceline
  :config
  (spaceline-helm-mode 1)
  (spaceline-emacs-theme))

According to the Spaceline documentation the projectile-root segment is defined but not used in the default themes. I tried to enable this with

M-x spaceline-toggle-projectile-root-on

but this has no effect. Is it possible to enable this in the default themes or do I have to build my own mode line?