Hey all, welcome to the forum!
The onle way I know of to build realistic palm trees is to go to the local garden center and buy a palm tree. I'm not trying to be funny, but my personal view of Garden railroading is to use real plants and leave the artificial to the indoor scale crowd. It's been my experience that artificial trees on an outdoor railroad look, well, artificial. That doesn't mean you won't be able to build some that are convincing, G railroading means experimenting, try it, if it works out then post the results for us all to enjoy!
The Dixie D Short Line "Lux Lucet In Tenebris Nihil Igitur Mors Est Ad Nos 2001"
Not sure about realistic - Indoor or outdoor is an important matter
anyway - some ideas
http://www.zeitcom.com/majgen/22palmsc.html
http://www.geocities.com/bkempins/ASMMain/PalmTrees.html
http://www.miniaturetree.com/viewcategory.asp?DirID=79
http://zelmeroz.com/canesig/model/handbook/17_palms.pdf
hope this inspires some ideas
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