There are so many lovely plants to choose from you would have to narrow it down a lot before we can offer any real help. Can you post a photo or two? Which part of the country are yo in? Are you very near to the sea? Which colours do you like? Do you want a variety to last for a long flowering season? How big is each flower bed? Do you want them all the same height? Do you want scent or colour? (you can have both if you wish).

Will you use the gravel part as a patio? I'm struggling to see how this front garden works in relation to your home (not sure how else to describe it). If you'd use it as a patio, I'd want it screened from the road in some way. I'd probably put ornamental grasses there. Maybe in pots, depending what's under the gravel. Then you could draw a circle in the 'flowerbeds', with the path running through the middle and either fill the circle with grass or with gravel and put plants along the outside. I'll see if I can mock something up for you. Hold on...

Lavender should do well if it gets sun most of the day. Look up some English varieties as these can cope a little better if you get cooler temperatures. Only thing with lavender is that can go a bit woody after a few years so you may need to take cuttings or replace. Hydrangeas like those in the photo are thirsty plants and can get fairly large and probably better suited if the border is about a metre deep. Roses would look nice tho, look for patio roses that stay fairly compact and improve soil with compost and manure. Another option is Salvias (or sage) there’s plenty of varieties including many blue ones so worth shopping around. And how about some white alliums for height, these are bulb plants so they don’t take up too much space (see pics below). When shopping for plants look up their individual requirements and eventual height and spread and this should help narrow down options. The RHS website is a great resource with loads of ideas and info.

Most perennial flowers die back in winter, bursting back into growth in spring and summer. I would suggest small evergreen shrubs which flower in spring and summer but keeps its leaves during winter. Looks a nice sunny spot so I would suggest Cistus which has pink or white flowers right now. Another good small evergreen in Hebe which forms a neat mount with purple or white flowers in summer, there are many, many varieties. You could also add a ground cover shrub rose which although not fully evergreen they flower all summer long and are not tall. The first picture is my shrub rose called Laura Ashley (there are many varieties), the second is my Cistus and the third pic is a Hebe. All they ask is a good watering daily, unless it’s raining, to get their roots established, and a handful of growmore or any other feed, in the spring. Once they are established then they won’t need much watering.