As a 3rd party add on to Vectorworks, we are curious if anyone has tried the free sample art and would appreciate any feedback. HDI is developing a scaled plan view library and is going to ask for suggestions of plant material from users. Thanks.
handdrawnimages.com has free tree and landscape textures available for download. HDI offers 3 Collections and a Designer Series of layered files of trees, shrubs, flowers and more in high resolution (300 dpi) file formats including: PSD, TIF & PNG. Most feature over 300 individual textures with alpha channels. Impressive!