Hi, I think I would opt for some good quality fake lawn as it looks like it would be a nuisance to mow and turf/grass may be difficult to maintain as it looks like you’ve got a lot of clay. You could try something like cosmos if you want a splash of colour though would probably have to put seeds down next April or so. The flowers last for ages and just take a bit of watering and occasional dead-heading. Here’s a photo from my parents’ garden from the weekend - really colourful!

The only way to get this right is to create a carefully scaled plan. One thing which would make the result a lot better is to make the 'roundabout' a raised bed so that you have some changes in level. That would also mean retaining some of the 'dig out' where you are extending the driveway. If you are extending the existing driveway by more than 5 square meters (which you will be), it needs to be a porous surface or have planning approval if it is not porous (in the U.K. that is). A lot of contractors either don't know this or don't care. Drainage is a a huge issue for everyone, overflowing toilets are not good for anyone.

How about a sweet lavender hedge all along the front? It will create a visual barrier to drivers. You can them add other plants like Geraniums, Cistus, Euphorbias, Erigeron, Alchemilla Mollis etc and scatter some gravel in between. They don’t need much attention apart from a cut back in spring. They will need watering until established and the following year they will not need extra watering. Here’s some pictures to inspire! Cistus Lavender Geranium, front right (purple). Euphorbia, back right (lime green). Lavender hedge near path

This is what there is at the moment. but will be double storey.