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 résumé, I've decided that Judgmental Neil was wrong once again. Those colors are wonderfully useful in taming our 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 to us 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 bed border, and many gardeners use it in pots and hanging planters. Its flowers are purple, with a tip of the hat toward blue.
Trailing lavender lantana grows natively in Southwest Texas, and it grows luxuriantly in hot, sunny sites all over our state. 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 potatoes.
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Cape plumbago is a sprawling tropical plant with true-blue blooms. It grows to 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 North Texas.
Angelonias come in a variety of shades. They grow like miniature snapdragons, to 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 in midsummer. 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 our best salvias are perennials in Texas.
Verbenas are variably dependable. The variety Homestead Purple covers itself in masses of rich purple flowers each spring. It's a spreading plant to 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.
Vitex is called lilac chaste-tree. I have no idea why. Rather than trying to figure that out, most of us opt simply to call it vitex. It's a grand plant for early-summer color on 8- to 15-foot shrubs. Its elongated lavender flower sprays are popular stopovers for bees and butterflies of all types. It's drought- and heat-tolerant. Your main challenge with this woody shrub will be to allow it enough room (15 feet) to grow and bloom well. Full sun, of course.
Crape myrtles are probably best known for having those luscious red summer flowers, but pinks, whites, lavenders and purples are also quite popular. My two personal favorite crape myrtles of all -- the two I would plant if I could only have two -- are Catawba (10-foot purple) and Twilight (15-foot dark purple). They blend with any color of brick or stone. (Reds can compete with some brick tones.)
Passion vines are native in Southeast Texas, but there are many tropical types (not winter-hardy here) as well. Some have large white or red blooms, but many are lavender or purple. The plants grow luxuriantly, and along the way through the growing season, they will likely be a short-term food for caterpillars of the beautiful Gulf Fritillary butterflies.
Morning glories are annual vines, noted for their flowers that close by midafternoon. The Heavenly Blue variety has been around for decades, and it's still one of our finest. They grow all summer, then begin to bloom from late summer well into the fall.
Neil Sperry publishes Gardens magazine and hosts Texas Gardening, 8-11 a.m. Sundays on WBAP AM/FM. Reach him during those hours at 800-288-9227 or 214-787-1820.