PHLOX SPECIES AND CULTIVARS
Moss PhloxThese species seem to fall into a single group, although Wherry (1955) assigned them to different groups using style length and seed size. Some of the eastern species are well established in horticulture. The western species are grown mainly by western and European rock gardeners, since most of them are very difficult to impossible to grow in the eastern US. There are a number of cultivars that are hybrids of P. subulata with one or more of the western species. These can be grown well with care in the East. All do best in well-drained soil in warm sunshine.
Phlox bifida (Sand phlox)- Range: midwestern, Michigan to Illinois south to Tennessee and Missouri. Habitat: sand hills and rocky slopes. Height: 10 to 20cm. Flower color: lavender to white. Bloom time: spring. This species has deeply cleft flower petals that give the flowers the look of a ten-point star. The foliage is larger and coarser than the other two eastern species.
'Alba' - A white-flowered selection.
'Betty Blake' - This selection has dark lavender-blue flowers.
'Starbright' - Very deeply cut petals, lavender-blue flowers.
Phlox nivalis (Pine phlox) - Range: southern Virginia to Texas on the coastal plain. Habitat: open woods on sandy soil. Height: 10 to 15cm. Flower color: purple to pink to white. Bloom time: spring. This southern species blooms about two weeks later than P. subulata. They are very similar, but can be told apart by the length of the style. If you tear the flower in half lengthwise you will see that the style is so short in P. nivalis that the stigma is at the bottom of the tube. In P. subulata the style extends out to the end of the tube. P. nivalis is an excellent garden species and has been fully hardy for us in southwestern PA.
'Camla' is an old cultivar with very large light purple flowers. The plant I have seen currently being sold under this name is a purple-flowered P. subulata or a hybrid.
'Dark Eye' has pink flowers with a darker eye. This was a seedling of 'Eco Flirtie Eyes' and was introduced by The Primrose Path in 1990.
'Eco Flirtie Eyes' has large light purple-pink flowers on a vigorous plant.
'Polly Spout' is a light pink selection introduced by We-Du Nursery in North Carolina.
'Snowdrift' is a white-flowered selection from Niche Gardens, also in North Carolina.
'Winifred' resembles 'Dark Eye,' but the flower is slightly darker pink with less crisp eye markings.
(Moss phlox) - Range: New York to Michigan and south to North Carolina
and Kentucky. Habitat: rocky and sandy barrens. Height: 8 to 20cm.
Flower color: lilac and pink to white. Bloom time: spring. This species
is used widely for groundcover in the eastern US. P. s. ssp brittonii
is the Appalachian subspecies, found commonly in the shale barrens from
Pennsylvania to Virginia. It differs in being smaller, with finer
foliage. There is great individual variation in flower color and petal
shape within and between natural populations. Many cultivars have been
selected. These are the ones I have grown and that are seen in catalogs
in the US.
'Allegheny Smoke,' raised at The Primrose Path, has lavender-blue flowers with a deep petal notch.
'Appleblossom' is a vigorous selection with light pink flowers with a darker pink eye. This reblooms consistently in the fall.
'Beauty of Ronsdorf' is a beautiful selection by Georg Arends. I have seen this listed only once in recent years. The plant turned out to be my 'White Eye,' below.
'Betty' is a tiny plant from the Redfield garden in Connecticut. It is one of a small group that also includes 'Herbert' and 'Tiny Bugles,' with foliage and flowers of greatly reduced size. This one has purple flowers.
'Brittonii Rosea' = ssp. brittonii 'Rosea,' a plant with light pink flowers. This is so compact that I wonder if it is straight P. s. brittonii.
'Candystripe' is a renaming of 'Tamonongalei,' below.
'Crimson Beauty' is really red-purple.
'Emerald Blue' is the standard groundcover lavender blue.
'Emerald Pink' is the standard groundcover pink.
'Fort Hill' is a selection found wild in Ohio and introduced by Trennoll Nursery. This is pink-purple with a deep petal notch.
'Herbert' is similar to 'Betty' in size and has lavender-pink flowers.
'Ice Mountain' is a pretty little selection of P. s. ssp. brittonii with pastel-pink flowers. Presumably this was found at Ice Mt. in eastern West Virginia.
'Millstream Coral Eye' was bred by Lincoln Foster and has nearly white flowers with a large, dark pink central eye marking. This is a very handsome plant.
'Millstream Daphne' is a pink-flowered selection.
'Oakington Blue Eyes,' raised by Alan Bloom, has violet-blue flowers.
'Purple Beauty' has pink-purple flowers.
'Red Wings' has intense red-pink flowers.
'Scarlet Flame' has intense red-pink flowers.
'Tamonongalei' was the original name of 'Candy Stripe.' I think this refers to the nursery in Tasmania where the plant was found. The petals are variegated with pink in the center and a white margin.
'Tiny Bugles' is similar to 'Betty' and 'Herbert' in size and has nearly white flowers.
'White Eye' was a 1990 introduction from The Primrose Path. This has medium-pink flowers with a white central eye ring.
There is an excellent discussion of these western cushion phlox and their cultivation (in the UK) in Graham Nicholls' Alpine Plants of North America, and Claude Barr has a lot to say about them in Jewels of the Plains. Panayoti Kelaidis has good photos and comments on his blog. They are very difficult to grow in the eastern US. I have had a few grow grudgingly for a while in my raised open sand bed. They suffer from summer humidity and from winter wet, and growing them in pots in an alpine house would probably be best. They can be started from seed from suppliers like Alplains or bought as plants from Mt. Tahoma and other nurseries. Getting the seed to germinate is not usually a problem. I will comment only on the ones I have tried to grow.
Phlox alyssifolia (Alyssum-leaf phlox) - Range: northern Great Plains. Habitat: Grassland and open pineland. Height: 3 to 10cm. Flower color: purple to pink and white. Bloom time: late spring to early summer. Norm Deno has grown this successfully in a dry sand bed in State College, PA. I have tried it several times from seed, but my plants have grown extremely slowly and have not bloomed. At this time they are starting their third season and are about 2cm high and 4cm wide.
Phlox diffusa - Range: montane northwestern US and California. Habitat: rocky slopes and pumice fields. Height: 5 to 10cm. Flower color: purple to pink and white. Bloom time: spring to early summer. I have admired this many times in the northwest and have tried it in western PA. It has never survived the summer.
Phlox kelseyi - Range: western Montana, eastern Idaho, Wyoming. Habitat: saline or calcareous grassland that is wet in spring, dry in summer. Flower color: purple to white. Bloom time: late spring. This species seems a little more amenable to garden culture in the East than the other species and should be tried in different sites.
Phlox sibirica and ssp borealis
P. bifida × P. subulata - These resemble P. subulata with large foliage; the flower petals are deeply cleft.
'Ellie B.' has white flowers with deeply cleft petals.
'Millstream Jupiter' from Lincoln Foster has lavender-blue flowers.
'Snowflake' seems identical to 'Ellie B.'
P. subulata × western species - There are several short series of these hybrids from the UK, Germany, and the Czech Republic, as well as a few from this country. They are often referred to as "Douglasii hybrids" but when run through Wherry's key have traits that seem to point to other western species as more likely parents. They are not hard to grow with reasonable care in the northeastern US. Some of the flower colors are very intense. The plants are about 10cm high with fine needle foliage. They bloom with the P. subulata cultivars in the spring.
'Boranovice' presumably was raised in the Czech town of that name and has dark pink flowers.
'Boranovice III' has rich pink flowers.
'Crackerjack' has intense dark red-pink flowers.
'Keryl,' which has round blue-lavender flowers, appears to belong here.
'Laura' is a Lincoln Foster selection with pastel-pink, wide-petalled flowers.
'Ox Blood' ('Ochsenblut') also has dark red-pink flowers.
'Red Admiral' has strong dark pink flowers.
'Snow White' ('Schneewittchen') has round, white flowers.
'Tycoon' has intense pink flowers.
'Violet Pinwheels' is a new selection bred by Jim Ault at the Chicago Botanic Garden and not yet introduced (description). The parents are P. bifida × P. kelseyi. The flowers are purple aging to violet on a 4"-tall mound.
[Introduction] [What is a Phlox?] [Horticultural History] [Basis of Breeding] [Accounts of Species and Cultivars] [References]