Phlox may vary in season, height, color

by How Does Your Garden Grow? By Sharon Daniels

When you think of phlox blooming in warm-season gardens, what do you picture?

Phlox forms are widely variable. Earliest to bloom is native Creeping Phlox, brightening low banks and rock gardens now. It usually is an inch or so high but can mound up to six or eight inches. Usual colors are white, deep lavender or lavender-blue.

Summer Phlox, Phlox paniculata, which grows three to five feet tall, is another familiar favorite. Its fragrant flowers are either white, lavender, pink, rose or red, though seedlings tend to be purplish-pink. Some years ago I set out a white classic selection named ‘David’ especially because it resists the powdery mildew which often is a problem with phlox. Unfortunately I have had problems keeping it going because of grazing.

You may remember an old-fashioned, fragrant favorite in gardens of your parents or grandparents, or maybe you still have it. For various reasons, Sweet William disappeared from my parents’ property, but last year I was delighted to find it at a nursery, bought it, and hope it survives for many years.

Annual Phlox, P. drummondii, is another form often planted in beds for summer color. It comes in a range of hues, some with a contrasting eye. This phlox blooms profusely from early summer to frost if you pinch off faded flowers.

A reader wonders about similarities or differences between phlox and Dame’s Rocket, both growing in her garden and cherished. They belong to two different families but at first glance seem very similar in appearance.

It’s fairly easy to tell them apart. Phlox leaves grow opposite each other and flowers have five petals. Dame’s Rocket leaves are alternate, flowers are four-petaled. Phlox is native to temperate North America, the other is of Mediterranean/Eurasian origin.

If the name sounds familiar, Dame’s Rocket is a type of gillyflower referenced in Chaucer and Shakespeare and is commonly a cottage garden flower.

I briefly had Dame’s Rocket 40 or even 50 years ago but not since. Then in mid-spring 2019 four plants appeared here, perhaps thanks to wind or birds, spaced 10-20 feet apart, growing in sun unlike my long-ago plants. I won’t disturb these flowers unless they become too aggressive. They are in full bloom now and should remain attractive through summer. One happened to appear at the foot of a red ‘Knock Out’ rose and the colors are nicely complimentary.

The reader also noted that deer seem to leave Dame’s Rocket alone in her garden, and I agree. However, deer obviously find phlox tasty as they graze early on my Summer Phlox. That could help you decide which to plant.

Sharon Daniels is a Virginia Cooperative Extension Master Gardener volunteer.