Creating plant texture maps

I've had to create a large number of plant textures from scratch, and i'd like to share what i've learned.  I am not a professional digital artist, so you may already have better ideas about how to create plant textures - in which case, please give me some feedback!  Thanks.

original image
chopping away background
tracing edge of plant
turn on alpha and hand edit
finished result with black background
alpha map

Photography tips:

One you've got the photograph onto your computer, these are steps i do in PhotoShop:
  1. Crop the picture down to just the plant
  2. Use "Adjust Levels" to adjust the dynamic range.  You're going to need all the brightness and contrast you can get.
  3. Lasso any large areas that you know aren't part of the plant, and clear them.
  4. Now, if you have large areas of blue sky, you may be tempted to use "Select: Color Range" to select the "blue" and remove them.  Beware!  This is a very sloppy approach at best, and can actually make hand editing much more time-consuming. Instead...
  5. Zoom in, and use the Lasso to manually select all surrounding areas that you know are not part of your plant.  I just hold the shift key and select bit by bit until the plant is surrounded by your selection.
  6. Hold down shift, and use the Magic Wand tool with a large Tolerance (eg. 50) to select parts of the background that are showing through the plant.
  7. Once everything but the plant is selected, use "Select: Inverse" and Save Selection to create an Alpha channel.  The new channel will be white for all areas of the image representing the target plant.
  8. In the Channels palette, turn on the little "eye" icon next to all the channels.  You can now see more clearly the areas you missed.  Go back and add them to selection, and make the Alpha channel again.
  9. Now comes the fun part.  Deselect all.  Highlight the Alpha channel in the Channel palette.  Use the paintbrush and eraser tools to get rid of every bit of error.  The "red" alpha region should extend precisely up to the edge of the plant but no further.
  10. To test your results, highlight your RGB channels.  Load the selection from the Alpha channel, copy, create a new file with a colored background, and paste.
  11. When it looks good, load the selection, invert, and clear to black (more info).
  12. If you've got a symmetric plant you're going to use it for a X-billboard, resize the canvas until the axis of symmetry is in the exact center of the image.
  13. Resize down to an appropriate power of 2 in each dimension.