There are so many flowering plants to choose from it's hard to know which plants to pick; a good starting point, when thinking of buying or planting a new plant, is "Right plant right place" . A much used gardening expression which means for 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. But, to do well, Lavender needs the right growing conditions. Lavender likes it dry, and well drained and will struggle in gardens which tend to be wet, heavy clay or which become waterlogged, especially in winter. A lavender with it's roots in cold wet soil may not survive a winter, its not so much the cold, as the wet.
It is important to know this if you are buying a Lavender plant because if your garden and 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) a good alternative which will tolerate wetter conditions.If you have wet conditions it is better to consider growing different plants, such as Marsh Marigolds which will thrive and the Fritillaria melagris (Snake's head Fritillaria) which love wet. Check out the plant's preferred growing conditions and also how hardy it is, which means how much cold it will tolerate; more about frost hardy.
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 when 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 grown in those conditions.
As to which flowering plants you chose for your garden its really personal, what plants you like. Your garden just like house decoration or fashion, is a personal choice. On the various pages and links there are lots of really colourful garden plants so you can pick and mix what you like for your garden.
If you have shady conditions, or a shade area you need to select plants which either thrive shade or are shade tolerant and there are plenty to choose from, from tiny Pulmonia to large Rhododendrons. Ideas on the best plants for shade and also ideas for damp shade which plants favour damp or boggy conditions.
Climbing plants add height and colour to boards and are good for covering fences. Many climbing plants are vigorous such as Clematis and Wisteria, and may require a lot of gardening attention. Images, growing tips and ideas on climbing plants, illustrated is Passiflora, which looks exotic but is easy to grow and hardy.