There are so many flowering plants to choose from it's hard to know which plants to pick. A good starting point, when buying or planting a new plant, is "Right plant Right place" . This is a much used gardening expression, which means to achieve the best results, you need to plant the right plant in the right place, i.e. the right growing conditions. Sounds simple.
For example: Lavender is a lovely flowering plant, providing scent and colour in summer. It is very popular and widely sold at many garden centres and on line. To thrive, Lavender needs the right growing conditions which are dry, well drained and it will struggle in gardens which tend to be wet, have heavy clay soil, or which become waterlogged. A lavender with it's roots in cold, wet soil may not survive a winter.
It is important to know this when buying a Lavender plant. If your garden growing conditions are not suitable, you may need to think of alternatives, such as planting lavender in containers, or if you want clouds of blue, select a different plant which will tolerate the conditions better, such as Nepeta (Cat Mint) which will tolerate wetter conditions.
The right place does make a difference. Some years ago I had a fancy to grow a rose on a bank in the garden. The ground was hard, compacted shale and after digging, hacking into the ground for some time eventually the fork broke. I decided to abandon the project which I should never have started. The ground was far too stony and poor, the rose would never have thrived in those conditions.
As to which flowering plants you choose for your garden, it’s really personal, what plants you like. Your garden is just like house decoration or fashion, a matter of personal taste. On the various pages and links below there are lots of colourful garden plants so you can pick and mix what you like for your garden.