Any landscape designer will tell you that blue is the most difficult color to find in garden flowers. That’s one of the reasons that blue-blooming plants are so prized. It’s also because they’re cooling in face of 100-degree temperatures, and they blend well with just about any other color. So let’s feature some of the best of the blue plants that we do have. (I hope you’ll permit a gentle stretch into the near-purples to fill out our list.)
The best blue bloomers for Texas …
Some people refer to this as “summer snapdragon” because its flowers are borne in vertical spires, but it’s actually a much better landscaping plant. It blooms for five or six months and stays compact all the while. It comes in various shades, although we’re talking about bluish casts for the purpose of this discussion today. Mature heights vary from 15 to 18 inches. It’s great massed in beds, or many use it as the “thriller” prominent plant in their patio pots. Angelonias have become main stream landscaping additions in the past 20 years, and we’ve been graced by their presence.
This plant is Evolvulus, and it’s a charming little plant that ought to be tucked into a patio pot or a small spot near a patio or entry. Its leaves look a bit like Texas sage, but its blooms are a cheery bright blue. You’ll need to view it up close, but once you do, you’ll love it forever.
Looking for a fast-growing vine to cover a fence? Morning glories might be your answer. They’re annuals, meaning they germinate, grow, bloom and go to seed all in one growing season. You have to replant them each year. You might still have time to get flowers by planting them now, although late April or early May might be better next time around. The heirloom variety Heavenly Blue is still hard to beat. And just to have answered it, the plants will grow all summer, but they don’t start blooming until early fall. Don’t give them too much nitrogen, either, or they won’t bloom at all.
This is a Hall of Fame blue flower, and it’s a comparative newcomer. It’s from Australia originally, and we first learned of it about 30 years ago. It trails, growing to 10 or 12 inches tall. It’s great as a spreading groundcover annual, or you can use it in hanging baskets and tumbling out of big decorative pots. Blue Wonder was the first one, then New Blue Wonder, and the hits kept on coming. This is a plant you need to include every year. Easy and dependable, it’s the perfect blue flower for those Independence Day red-white-and-blue plantings.
There are several, but the most common blue annual types are selections of Salvia farinacea, mealy cup sage. Noted Texas plant man Greg Grant found and introduced the especially perennial form Henry Duelberg (named for the headstone in the cemetery where he found it). It’s nice grown alongside its white-flowering companion (and Henry’s wife) Augusta Duelberg. Indigo Spires is a richly dark blue form that is equally beautiful.
This is a tropical annual that grows to 18 or 20 inches tall. It grows best in the sun, perhaps with a little protection from intense mid-afternoon rays. Some of the prettiest plumbagos I’ve seen in North Texas have been massed in large decorative pots on city streets. Its sky-blue flowers tame the hottest day.
Botanically it’s Eupatorium greggii. This perennial grows to be 20 to 28 inches tall. It’s rather loose and informal, so you probably won’t want it right by your front door. However, that doesn’t seem to bother the butterflies. They flock to it unlike almost any other plant you might grow. It blooms from spring into the fall, and it’s eager to have a spot in a corner of your perennial plantings where it can remain undisturbed for many years.
If you grew up in Texas you saw this in the older parts of your hometown. Our grandmas grew it, and now we do, too. Fact is, it’s become one of our mainstay perennials. It came back into vogue about 25 years ago as independent retail garden centers starting asking their growers to produce it. Where you used to have to mooch starts from folks down the street, all of a sudden nurseries were well stocked come early fall. In fact, the butterflies usually lead you right to the plants. I’ve grown this lovely plant for most of my life. Its bloom time varies from early September into October depending on the year. Its foliage is fine-textured – so fine that you really don’t even notice the plants until it’s time for them to start flowering. Then all of a sudden, there they are.