I used to think that purple and blue flowers were for timid people who were afraid to venture into the vibrant reds, oranges and yellows. Now that I’ve added a few decades of Texas summers to my resume, I’ve decided that Judgmental Neil was wrong once again. Those colors are wonderfully useful in taming summer’s heat, and they’ve become my favorite plants of the summer.
I thought I’d share some of the best of the lavender, purple and blue flowers of summer. Even though these are the least common colors in gardening, there still are far more than we can pack into one column. Let’s arrange them according to height.
Fanflower came on the scene 20 years ago, and it has become a flower-fan favorite. It grows to 6 or 7 inches tall and sprawls to 24 inches across. It’s a great border for beds, and many gardeners use it in pots and hanging planters. Its flowers are purple, with a tip of the hat toward blue.
Trailing lavender grows luxuriantly in hot, sunny sites. As long as it’s kept adequately moist, there’s no heat too intense for it. It combines well with purple-leaf plants such as purpleheart, Persian shield and ‘Blackie’ ornamental sweet potato.
Cape plumbago is a sprawling tropical plant with true-blue blooms. It grows 15-18 inches tall and 20-24 inches wide, and the heads of cheery pastel blue are produced from spring until frost. It is not winter-hardy in many zones.
Angelonias come in a variety of shades. They grow like miniature snapdragons, 12-20 inches tall, and are delightful massed into the middles of beds, with taller flowers behind them and trailing plants in front. They’re also quite useful as the “thriller” plants in patio pots – that is, plants we use in the centers for the primary accents of the plantings.
Pentas also grow to 12-20 inches tall, but their flower heads take on a fuller, more rounded form. Flower shades include reds, pinks, whites and our spotlighted colors, purple and lavender. They grow best in moist, highly organic soils. They flower best with full morning sun, then a little shade during the hottest part of the afternoon. They’re also great in large pots.
Salvias bring us some of our best blue and purple flowers in summer and fall. Varieties like Henry Duelberg and Indigo Spires are richly dark blue, while Mexican bush sage (Salvia leucantha) is a lovely lavender-purple bloomer in late summer and into the fall. Many of the best salvias are perennials in warmer zones.
Verbenas are variably dependable. The variety “Homestead Purple “covers itself in masses of rich purple flowers each spring. It’s a spreading plant only 7 or 8 inches tall, but it’s reliably perennial, where many types are not.
However, if you want a summer performer, ramp your eyes up to V. bonariensis. It flowers at 4 or 5 feet, and it’s a magnet to butterflies from all around. Due to its height and wide open habit, it will need ample space. Mass it at the back of your flower garden, and plant complementary colors in front of it.