The answer to 'best time for landscape design' is that the best time to start planning and designing your landscape is typically in the fall or winter months. This is when landscape designers and contractors have more availability, and you can take advantage of the off-season to get your plans in place before the busy spring and summer seasons.
By starting your landscape design process in the fall or winter, you'll have plenty of time to research, plan, and finalize your design before the weather warms up and the busy planting season arrives. This will allow you to get your landscaping projects completed more efficiently and potentially save money by avoiding peak season rates.