1...Create Doc with White BackGround.
2...Add New layer and fill with default rainbow gradient. Set this layers opacity to 75%.
3...Apply Hue & Sat to gradient to suit (Image/Adjustment/Hue & Sat). Apply 20 to 30 pix Gaussian blur if gradient becomes blocky.
4...Apply Brick Texture to suit. Filters/Texture/Texturizer. Example:Scaling=200%, Relief=12, Light Direction=Bottom Right, Invert=Enabled. (Filters/Texture/Texturizer)
5...Turn off both layers (Click eye icons)
6...Add leaves using Custom shape tool (Change default shapes to Nature by clicking little arrow on Shape flyout). Choose White for fill colour.
7...Use Path selection tool to transform and move leaves.
8...Merge leave layers (Layer/Merge visible).
9...Add new layer and group with leaves layer (Hold Alt key down and click between the two layers in the Layers palette).
10...With New layer active, drag the rainbow gradient on the canvas.
11...Turn on Brick wall layers then select leaves rainbow gradient layer and change layers opacity to 80%.
12...Apply Hue & Sat to leaves rainbow gradient layer to suit.
With the leaves rainbow gradient layer selected you can use the Lasso selection tool to make a quick selection around individual leaves, or groups of leaves, and change thier Hue & Sat individually (The selection does not need to be precise). You can of course avoid steps 6 to 8 and create the leaves as Doodad described .
Sark