Shadowmap is a great and playful tool to explore sun positions and shadows

It works in a browser and has distinct levels of detail and analysis tools. Not directly applicable to SketchUp, it does offer a refreshing interface to help with site analysis.

2024 saw a rival to the official Basecamp biannual conference emerge; the SketchUp Summit, organised by Michael Brightman.

Some of the talks from that event have started to appear on Youtube. The first is Justin Geiss (SketchUp Essentials) on Extensions and how to use them.

Also, currently available is Nick Sonders overview of designing buildings on challenging terrain

Berms and bioswales or banks and culverts as we might call them in the UK requires a simplistic approach to organic surface creation. SketchUp YouTube channel has a tutorial for that.

If you do not already follow the TutorialsUp channel on YouTube; subscribe. Aimed at more specific and sometimes complex modelling problems, it is inspiring to appreciate what can be achieved and the tools required. A lot that applies directly and indirectly to landscapes and gardens.

A suite of extensions that I have increasingly come to value are those by Curic. He uses a Gumroad account, but this can be accessed from the Extension Warehouse inside SketchUp. I only recently found his 5D+ extension which can automate a lot of the things we need to do in the background when setting up drawings (assigning groups and components to tags for example. There is another product Condoc by Brightman studio, but it seems complex and a unnecessarily extensive for garden type projects. 5D+ is a relatively low, one-time payment only, which is refreshing.