Over on Real Effects Studios is a WIC (weekly image contest) similar to the WC here and this weeks topic is Plant and specifically organic so here is my entry WIP:
i still have to make it bigger, add ao, fix lighting and some textures, and maybe do some more modeling as well as make a old wooden board frame around it but this what i have so far - enjoy!
Prince
here’s an update - maybe more will come - but i think it is pretty much finished now… 4 days early! 
I like the feel and look of the cactus …
However the grass in the background is too distracting and doenst really look like grass anyway .
Heres a thought though , forgive me if I dont know better … Im from canada … you know , Igloos and shit LOL
but Dont cacti primarily grow where there isnt much vegetation ?
I think it would do this image wonders to ditch the grass and work on the sand and rocks …
maybe ad some cacti in the background .
actually i live in Texas right now and i am looking at the cactus i took that picture from an it looks just about right! grass (more like weeds and hay) grow four feet tall in some places…grasses (some anyway) like cactus can grow in no water areas not no grass areas! thus the grass (which does look more like wood straw and thatch) is accurate…i am going to make another version soon with rocks and more scarce desert like ground with nice DOF…
very nice. artistic too. But looks a little rounded but may be light reflections as I remember (Texas, Arizona) they are very flat. Also needs some thorns. But other than those suggestions truth is I like it. Your scene captures the mood well.
Paradox