Summertime Blues: Blue Flowering Plants for Hot Summer Gardens

There’s simply no other way to put it. This summer’s brutal heat has been just that – ruthless. With the once thought to be relatively clement temperatures of June climbing to record highs, adjoined by heat indexes soaring well over 100 and several weeks of insufficient rainfall, how can gardeners not be faced with those dreaded summertime blues? Emerald seas of St. Augustine and Centipede lawns have prematurely faded to crispy toffee brown, while in beds around town, tender plantings of periwinkle and zinnias have shriveled to almost nothing.

Like many Louisiana gardeners, Ron and I have spent much of this summer hand watering our flowerbeds (and will no doubt invest in a sprinkler system for summers to come). Our house being one of the seemingly two in our neighborhood without a swimming pool – like my husband, my brother-in-law naturally doesn’t see the attraction in these summer splendors, either – I have to look on with envy as neighbors on either side of us beat the heat with incensed cannonball competitions and hours of endless races down water soaked slides. As a consolation, Ron bought me a personal misting fan for use while I bake alone in my beach chair, listening to the frenetic splashes around me. Of course, this doesn’t rid me of my summer despairs, but it certainly inspires me to cool off the garden. With our fiery red tomatoes, carrot orange milkweed, and golden coreopsis, our sizzling hot flowerbeds can undoubtedly be toned down with a few tranquil blue blossoms. Say goodbye to your gardening summer doldrums by integrating refreshing blues like ‘Endless Summer’ hydrangeas, blue daze, vitex, plumbago, and ‘Mona Lavender’ plectranthus. Any of these cool blues will give you lasting color all season long, while instantly creating relaxing gardens and peaceful patios.

‘Endless Summer’ hydrangeas, the latest edition to a dynasty of old garden shrubs, are reliable shade lovers that bloom from late spring through summer. Their corpulent azure heads though, are far from antiquated, since unlike their ancestors, these youthful beauties incessantly flower on both old and new wood. ‘Endless Summer’ hydrangeas average four to six feet tall and prefer direct morning sunlight and afternoon shade. Grow them alongside summer flowering ‘Bears Breeches’ (Acanthus mollis), hostas, and impatiens – Japanese maples and Eastern redbuds are other superb accents for these blue beauties – or capture their old-fashioned grandeur in individual pots on patios or porches. No matter where you decide to grow them, make sure to brighten dinner tables and breakfast bars with their fresh cut blossoms; summer-long flowers insure plentiful blues both indoors and out.

Blue daze (Evolvulus glomeratus) is another excellent choice for healing the summertime blues. Its cornflower blue eyes open brightly with the sunrise, handsomely complementing its silvery green foliage; flowers close in the evening as the sun retires, only to reopen vivid sapphire the following morning. Blue daze thrives in full sunlight and well drained soil. It forms a low mound that reaches 12 to 15 inches tall and almost 18 inches across, making it perfect for hanging baskets, combination planters, and for use as groundcover in perennial flowerbeds. These vibrant blue flowers bloom profusely from mid spring through autumn, but go dormant with winter’s first frost. Create an outstanding show of color by integrating blue daze with ‘Butterfly Red’ pentas, ‘Landmark Yellow’ lantana, and ‘Senorita Rosalita’ cleome. ‘Mystic Spires’ salvia, pineapple sage, and ‘Tiger Eye Gold’ rudbeckia also make charming companions.

Vitex (Vitex agnus-castus), also known as chaste tree, is an exceptional old garden shrub averaging 10 to 12 feet tall. Although tolerant of most growing conditions, vitex performs best in full sunlight and well drained, sandy soils. Its upright arching branches elegantly spread into a dense canopy of marijuana-like leaves atop a smooth, multi-trunk base. From late spring through fall, its aromatic silvery green foliage lavishly adorns the tree, and in early summer this traditional southern favorite is further heightened by spikes of brilliant indigo that passionately glow with life. Spotlight your vitex by planting it as a single accent shrub in the landscape, or integrate it near other large shrubs or small trees like ‘August Beauty’ gardenias, sweet olives, camellia sasanquas, and Japanese magnolias. ‘Knock Out’ roses, ‘Burgundy’ loropetalum, and esperanza also look stunning in front of chaste trees. Vitex, like hydrangeas, make admirable cut flowers for summer get-togethers as well – their freshly scented leaves and bluish purple spears will no doubt create a conversation piece atop any table they embellish.

Consider also including blue plumbago (Plumbago auriculata) in your summer flowering garden. Native to South Africa, this semi-woody perennial grows best in full sunlight and well drained soil. It averages four to six feet tall, while keeping a loose, sprawling habit with its glossy yellow green foliage. From late spring through autumn, clusters of sky blue flowers hang like phlox atop this rugged summer rambler. Remember that plumbago is semi-tropical, so it may not survive severe freezes – for best results, plant this blue beauty on the south side of your house so as to protect it from harsh winter winds. Incorporate plumbago in landscapes near ‘Pink Knock Out’ roses, ‘New Gold’ lantana, and ‘Butterfly Red’ pentas. Let plumbago brighten your patio or poolside as well, by planting single shrubs in large planters; selectively trim them throughout the growing season for optimum blooms and appearance.

No blues garden is complete without ‘Mona Lavender’ Plectranthus. This sensational summer bloomer is fast becoming popular in the South, and it’s no wonder, since from spring through fall, light lavender spikes bloom continuously against downy greenish purple leaves. Flowers appear almost iridescent, while the entire plant is cast with rich plum violet. ‘Mona Lavender’ prefers morning sun or filtered light, and averages 18 to 24 inches tall. Plant it in baskets beneath your covered arbor, or mix them in large planters with ‘Kolibri’ English ivy, ‘Dazzler Punch’ impatiens, and ‘Snowtopia’ bacopa. ‘Mona Lavender’ also works well in shaded flowerbeds near Acanthus mollis, variegated hostas, and ‘Endless Summer’ hydrangeas. Whatever your preference, don’t let the summer doldrums get you down; enliven your beds and patios with any number of cheerful blue blossoms. ✦