What can i add for colour?

[onebusymum]

Im trying to sort my garden out, it really needs an injection of colour, what can i add that flowers most of the summer?

Lavender seems to flower for a long time, as do hydrangeas.
Crocosmia are lovely and bright in the summer, and grow easily, and Bowden Nerini are good for a late burst of colour - bright pink flowers from October onwards. You could also mix some spring bulbs in among the plants you already have, and that way have something in flower for most of the year. Fuschias are in flower for a long period of time, from my experience, but the really gorgeous one that flowered for months on end in my garden last year turned out not to be hardy , so make sure you get something appropriate for your area.
Could you grow a flowering climber up the fence visible in the top right of the photo? If you planted two or more climbers with different flowering periods, you could have flowers for longer. Depends on what the light is like for what you'd put there.

Or you could even go for a plant with colourful leaves (lots of lovely dwarf Acers to choose from), or a climber with colourful leaves up the fence at the top.

I'd definitely go for something along the back fence. Clematis, climbing rose, or climbing hydrangea, maybe sunflowers planted in front. In the beds, as pp suggested hydrangea and fuschia. Also penstomen and pinks have long flowering seasons. Hebes have interesting leaves and the flowers last for a long time. Then again there's always cranesbill geraniums, different ones flower all through the season.

You have a lot of potential for flowering climbers here. You could use clematis that flower at different times and annuals such as sweet peas, ipomoea, lablab and so on.

For the border, if you aren't planning on any redesign I would suggest using annual bedding or containers for instant effect. Are you looking to plant any perennials at this stage? If so what is the aspect of the border to the left?

I do have some perennials in the side border.
ive just moved a climber in a pot to the bottom and it has broken some of the bareness up.

Mallows.
I planted some last year and they've just exploded this year. Beautiful colour, and quite tall with good spread.

Dahlia have beautiful colour too.

I'm a fan of the cheerful self seeders - California poppies, snapdragons, nasturtiums - the first two will come up with different colours now and again and are just no trouble at all. Nigella (love in a mist) is also easy and will come up for you again next year, with lovely seed pods as well as the gorgeous blue flowers.

Salvias come in all sorts of colours. I have one that flower s from may to October called Hot lips. Just cut it back to a few inches in autumn

Depending on how much sun your garden gets, I recommend Cosmos. It's very easy to grow, flowers for a long time and, if you buy it as a bedding plant, should be pretty cheap too. The only downside is that it is an annual, but it is great for some instant colour.

I agree with the suggestions above to add some climbers, but it's difficult to suggest suitable ones without knowing how much sun the wall gets

OP, regarding climbers, you have wall/trellis on three aspects so you have plenty of choice. The climbers Boston Ivy, Virginia Creeper for autumn colour might also be nice.

The RHS website, plant finder section could be useful, allowing you to select all the variables and coming up with suggestions for your particular situation.

For colour, I love my Margeurite, crocosmia, some tall, large headed daisies (don't know proper name, sorry!) Hebe and little red robins/Photinia

I have some tall stalks with lots of clusters of yellow flowers on that seem to be self seeding (need to do some plant ID threads!) and Maltese Cross(?) (tall with pink heads that self seed)

Geranium Rozanne will flower all summer.
Shrubs philadelphus, deutzia, kolkwitzia, buddleia, wiegela, all flower at different times through the summer.
Cosmos are a good annual .

Roses would fill that space between the flower bed and the ivy on the wall. Modern ones will repeat flower. Read the labels in the garden centre to check which are the best height for your space.