You may want to try suplabel(). Suplabel() can provide overarching axis labels or titles for a group of subplots.
From the example in the synopsis:
subplot(2,2,1);ylabel('ylabel1');title('title1')
subplot(2,2,2);ylabel('ylabel2');title('title2')
subplot(2,2,3);ylabel('ylabel3');xlabel('xlabel3')
subplot(2,2,4);ylabel('ylabel4');xlabel('xlabel4')
[ax1,h1]=suplabel('super X label');
[ax2,h2]=suplabel('super Y label','y');
[ax3,h2]=suplabel('super Y label (right)','yy');
[ax4,h3]=suplabel('super Title' ,'t');
set(h3,'FontSize',20)
