Small flowering shrubs for planting next week - and where to buy?

[Walkingtheplank]

I'm looking to plant some shrubs next week when I have some time off. I've left it a bit late to plan and I'm not confident that the local garden centre will have a great choice. Are there any good online retailers that would deliver in a few days?

I'm looking for some small flowering shrubs to fill gaps that over the years I've planted bedding plants which have had variable success. I have a mostly clay soil which doesn't help. I'd like some pretty colourful plants. We have quite a few erysimum which absolutely flourish but I'd like something different for variety.

Any ideas?

Heathers, hebes and azaleas would be my choice

@Walkingtheplank Is your soil alkaline or acid?

Erysimums tend to like alkaline soil, so the plants suggested by @FLOrenze might not do very well where you live, because they prefer an acidic soil.

I'd not thought of pH level! Will have to work that out tomorrow.

I have clay soil and a garden full of Azaleas, Rhododendrons, Abelia and Heather. They are all happy and many have been growing in the clay for 20 years. I buy at our local garden centre and specifically chose dwarf rhododendron as they only reach 1.5m rather than become HUGE! The Heather has started flowering now (more will come into flower in the spring), the Azaleas and Rhododendron start flowering in the spring and continue into the summer and then the Abelia starts in the summer and flowers right through Autumn- they look fantastic at the moment! All are evergreen and the Abelia have gorgeous pink foliage at the moment...

Clay soil can be acid or alkaline, depending on the local geology.

Camellias
Daphne
Gardenia