The first thing to do is decide if you want garden software or garden design software:
Garden design software
Needs elements for drawing, possibly CAD (Computer Aided Design) and graphics manipulation or visualisation.
Garden software
Can be something like a garden maintenance program, a record keeping program, a journal or diary or encyclopedia as well as garden design.
Before choosing your software, think about what it is you actually want to achieve - make a list, then check that off against the software features. Do you want a tool for garden record keeping, something for planting plans, garden design, a plant encyclopedia or something else?
Also, for business, think about how you expect to use the results with your clients.
Software takes time to produce - if it is free AND it does everything that you need, then you can probably count yourself lucky.
Some software is country specific - For example, Complete Gardens Plant Finder is developed specifically for the UK.
Make sure you see a features demo in one form or another, if there is a trial version that you can try, then do have a go; however, for smaller companies, the time and cost of producing working trial versions can be prohibitive, so a features demo maybe what you'll get.
buy planting plans
If you are only spending a little money for 'fun' then this is perhaps not that important - but if you are buying for education or business, then your choice can have a bigger impact. Taking the time to work out what you want from your garden software could save you a lot of time, effort and money.
How easy is it to learn garden software?