You can try to make it a vector. Separate the parts from a photo by using Photoshop's normal pro quality background removal methods such as clipping paths (the magic wand is mostly useless) and paste them one by one into a vector drawing program which has bitmap tracing. Here's an example:
This is in Inkscape. Only a couple of red flowers are pasted to it. Tracing with 3 colors (one is for the background which is removed) created 2 vector shapes. They are colored separately and moved on a pink background shape.
Tracing with one color more can create more plausible result, but recoloring becomes much harder (=more colors to match):
Limited number of colors can fade too much geometric forms of the objects. Experiment a little in Photoshop with the curves tool to get a well traceable image. You can also trace with even more colors and make an union of some areas so that the remaining areas present the geometry acceptable.
In vector drawing program you can
- build easily a plane filling pattern from the traced and colored shapes.
- edit paths for example to remove excessive details.
In my example no path edits are applied, but tracing option Smooth=ON automatically makes edges a little simpler.
Inkscape is not effective for print preparation because it knows nothing of CMYK nor Pantone color printing. You must fix the colors in Photoshop. For printing it's best to make the vectorization in Illustrator or other proper print aware program.
