The phlox family is the most interesting one. Besides phlox, it includes polemonium, gilia, and cobaea.
Many of us know the native polemonium with its lovely blue flowers and compound leaves which is quite common in many of the woods from New York to Minnesota to Kansas to Alabama.
We sometimes call it Jacob’s Ladder, other times Greek valerian. Even more useful since it is taller, growing, and showier, it is one of the few European members of the phlox family— Polemonium caeruleum.
Several Gilia Species
There are quite several gilia species up and down the Pacific Coast. Probably the showiest one we often grow in our gardens is Gilia rubra, sometimes called the standing or tree cypress.
It usually acts more or less as a biennial, growing one year and blooming the next. It is quite showy with pink or, more often, bright red flowers on three to 6-foot spikes.
Cobaea Scandens
And probably very few who grow the charming cathedral bells Cobaea scandens, realize it is a member of the phlox family introduced from Mexico. If you have never grown it, it is well worth trying.
Genus Phlox
The genus Phlox is fascinating and grows from relatively high altitudes in the mountains to the lowlands in the prairies and the plains. Except for one Siberian species, they are all natives of America.
Phlox Drummondii
Probably best known of all Phlox is the annual Phlox Drummondii, which grows wild through the gulf states.
The hybridizers have worked on these, and a grandiflora class grows 15” to 18” inches high.
It is especially nice for cut flowers as well as garden use. For example, the cuspidata group has irregular star-shaped flowers in which the petals are rather deeply cut, giving a more airy effect than usual.
For those who wish to have lower-growing plants, there is the nana compacta group which comes in separate colors and a mixture.
Phlox “Twinkles”
A more recent introduction is the globe phlox which has a rounded ball-like growth habit. The 1957 All-America winner phlox ‘Twinkles’ is in this classification.
This grows about 8” inches high and has a variety of colors.
Although the annual Phlox is native to areas where summers are hot, they do not always continue to bloom through all of the hot summers of the Midwest. They are more satisfactory where it is slightly cooler.
Perennial Phlox
The hardier perennial phlox offers a tremendous variety of forms. For example, the moss-pink Phlox subulata grows wild on hot sandy banks, usually in poor soil, from New York to Michigan to Florida.
Wide varieties have been selected through the years until today. They are white, pale blue, lavender, red, and pink.
They vary considerably in the size of the flowers and the habit of growth. One of the loveliest is ‘Vivid’ with soft pink flowers.
If you wish for a strong growing plant for a ground cover, the old lavender variety ‘Lilacina’ is vigorous with excellent foliage throughout the growing season and often through the winter.
Some of the varieties available at nurseries are the following:
- ‘Alba’
- ‘Atropurpurea’
- ‘Blue Hills’
- ‘Crimson Beauty’
- ‘Emerald Cushion’
- ‘Rosea’
- ‘Vivid’
- ‘Snow White’
- ‘Lilac Queen’
Many nurseries carry their selections with darker or lighter-colored flowers.
In general, Phlox subulata should be planted in full sun in not too-rich soil. This is because they thrive for many, yet they are considered difficult to grow in other gardens.
Several alpine species grow through our western mountains. Unfortunately, all these will grow in rather poor soil—sometimes almost in gravel.
The Wild Sweet William
Phlox divaricata differs from most other phloxes in that it usually grows in the shade. Its 8 to 12-inch tall stems with lavender, pink, or white flowers make a wonderful addition to any garden.
Although the variety ‘Laphamii’ is supposed to be large-flowered, equally good plants can be found along many roadsides and woods.
The size of the flower, the color of the flower, and the shape of the petals vary tremendously. In the home garden, they may thrive and self-sow to such an extent that they can almost become a pest, yet in other gardens, they will be difficult to establish.
Try them in a variety of locations in your garden and see if one area is not more satisfactory than the other. Ample organic matter in the soil will greatly increase their spread and bloom.
For Summer Bloom
The taller phlox that bloom during the summer are varieties of Phlox paniculata. They come in many colors, and the garden should not be allowed to be overrun with the common magenta-colored variety.
These colors include white, cream, light pink, dark pink, salmon, rose, bright red, lilac, magenta, and even purple. Unfortunately, there is no more showy or satisfactory flower for mid to late summer.
They thrive in the sun or even in some shade and are perfectly hardy. Their big objection is that they set seeds profusely.
The seeds germinate rather easily, and one may soon have a host of seedlings approaching the wild parent in color, an ugly magenta.
Unfortunately, these ugly seedlings soon crowd out the good varieties. These summer phlox are so easy to propagate from root cuttings that when they are dug, every little piece of root, even a half-inch long, may send up new shoots.
This makes it difficult to eradicate unwanted seedlings. The moral is “never let your phlox go to seed.’’ Never plant good, new varieties in the same bed for at least a couple of years.
The Garden Phlox Has Its Troubles
Spider mite (red spider) loves it. The bug feeds on the upper surface of the upper leaves causing them to have light-colored spots.
Phlox can get powdery mildew disease during late summer. And then phlox just have poor growth, particularly older clumps.
The best all-around way to handle phlox is to cut off the stalks in the fall and burn them to destroy any bugs’ eggs.
Dust or spray with an all-purpose material such as you use for your roses, once a month from mid-May through the summer. This should control many of your difficulties, the spider mite, the plant bugs, the mildew, and leaf diseases.
Phlox Suffruticosa
Phlox suffruticosa blooms a few weeks earlier than ordinary garden phlox. ‘Miss Lingard’ has snowy white flowers and it is wonderful.
Although there are some other varieties of suffruticosa, their colors are not as clear as desired. For example, ‘Miss Verboom’ has a lavender rose flower.
Other Phlox Varieties
There are other varieties of phlox— the native creeping one, Phlox stolonifera, which grows in the shade; Phlox amoena 6″ to 12″ inches high; and Phlox pilosa 12” to 18” inches tall.
The low-growing kinds of phlox are valuable in the walled garden, as a ground cover in sunny areas either on level ground or banks, as the edging for flower borders, in the wild, and in the rock garden.
The taller forms are useful in the flower border, in rows in the garden for cutting, in front of shrubs and evergreens, and in the back of dwarf shrubs and evergreens.
One can even naturalize the garden phlox like a sweet rocket (Hesperis), coreopsis, gaillardia, hardy sunflowers, and others in the back corner of the garden where nature will take over.
44659 by Victor H. Ries