Blue flowers are perennially popular. I am asked for blue flowers probably more than any other colour. There are very few true blue flowers; most are a variation of purple or pink and I think it these tints and hues that make blue flowers relatively easy to combine either with themselves or contrasting or complimentary colours.

These plants are all well-suited for a sunny border. In gardening terms that means a border that receives sunlight for at least six hours a day. Some will tolerate a bit less but you won’t see the best of them.

When starting a new border I like to start with the tallest and/or most structural plants. A clematis like this Romantika will clothe a fence in midummer without taking up a lot of space. You could also use C. Jackmanii or C. alpina for a paler blue in late spring.

There are not too many blue-flowered shrubs to choose from. This Hibiscus will flower for a long time and can be pruned if it gets too large. An alternative would be to choose a Ceanothus but as they don’t like being pruned you need to be careful to select one that will fit your space at its maturity.

Next I like to think about taller perennials. This combination of Iris and Echinops will give you tall blue flowers from May through to August. If you’re lucky the Echinops may give you a second flush or flowers later in the summer. I also like Agastache Black Adder but I’m afraid I’ve long given up on Delphiums and Lupins as they are just too popular with slugs and snails. The taller Agapanthus are also good value, one of my favourite is A. Navy Blue.

Aquilegia Blue Barlow straddles the space between taller and shorter perennials but it is a great shot of darker blue in April and May. Other blues in this space could include Penstemon Alice Hindley and Nepeta racemosa Walker’s Low.

On to lower, more spreading perennials. Geranium Rozanne was voted plant of the century by the RHS and really it’s not hard to see why. It flowers from May to November and doesn’t need to be dead-headed or cut back until spring the following year. And my personal favourite, Salvia nemorosa Caradonna. Ok, it’s quite purple, but I love the black stems and it will often give a second flush if dead-headed.

Scabiosa Butterly blue is one of my favourite blue flowers and these, like all blue flowers, are really popular with pollinators.

Spring bulbs in blue are a bit harder to find. I like purple crocuses and they will spread quite slowly through the border. Muscari, grape hyacinths, are a really nice bright blue. The best blue bulbs are Camassias but as these prefer damp soil and dry sunny border is not always the best place. Of course there are bluebells. Unless you really like the Spanish hybrids I think native bluebells are best shown off in woodland rather than a sunny border.

These are just a slection of some of my favourite blue flowers, you may have a few of your own. Getting a good combination of height, flowering times and plant and flower forms will make your border look more interesting. And of course, you’ve heard it many times before, unless you’re planting up a pot, do try and get several of the same type to make a good show.

If all blue is a bit too much then it is an easy colour to combine with others. Try yellow or bright green for a zingy spring feel, orange for a fully saturated late summer look. And pale or bright pink works for a more traditional scheme. Or throw out the rule book and mix in reds, oranges and purples for a surprise.