I highly recommend the Oxford College of Garden Design. The Diploma course out-shines the competition. The course content is vast and highly comprehensive. It has far exceeded my expectations.
The Oxford College of Garden Design is a very thorough course which includes; design, planting, CAD training (Vectorworks & Sketchup), technical drawing, construction methods, contract documentation, pricing and marketing. All lectures are pre-recorded videos , which are very clearly presented.
What sets this course apart from other online courses is the weekly webinar with the course leader and peers. This provides instant clear feedback to make learning fun and effective. Between the weekly webinars, feedback and support is provided very promptly via the virtual classroom.