Time is not lost

These are some lovely tulips that I bought my sister for her birthday this week (then 'borrowed' a couple to photograph!) I wanted to have a go at combining different sized images in PS using canvas resizing and layers. Turns out it's very simple, yay. Now if anyone can tell me how to merge the back grounds so they even out and appear as one I would be very grateful. Hope your all having a lovely weekend. I'm not looking forward to losing an hours sleep tomorrow but will appreciate the lighter nights.