Bulletin: Number 588.
Publication
Info:
Bulletin 588
March 1934
History,
Culture, and Varieties
of
Summer-Flowering Phloxes
A.M.S.Pridham
BRIDESMAID, A TALL, VIGOROUS PHLOX
The individual florest are white,
with a rose-pink eye which is slightly diffused over the petal so that in mass
the variety appears to be of very delicate pink color. [подпись к фотографии]
Published
by the
Received
for publication
2
CONTENTS
PAGE
Botany of the phlox…………………………………………………….. 3
Botanical
description of early-flowering species……… 3
Section
Subulatae ………………………………………….. 3
Section
Divarikatae ………………………………………… 5
Section Ovatae
………………………………………………. 6
Botanical
description of Phlox paniculata ………………
7
History of the phlox …………………………………………………… 8
The first
hybrids ……………………………………………………. 8
The suffruticosa varieties ……………………………………… 9
The decussata varieties ………………………………………..
9
Dwarf
perennial phloxes …………………………………………12
History of
phloxes in American gardening ……………..13
Culture of the phlox ………………………………….............. 14
Description
of the plant …………………………………………14
Horticultural
value ………………………………………………….14
Preparation
of the soil ……………………………………………14
Planting
………………………………………………………………….14
Cultivation
……………………………………………………………..15
Propagation
……………………………………………………………16
Diseases and insect pests of phlox …………………………..19
Varieties of phlox ……………………………………………………….20
The suffruticosa group……………………………………………20
The decussata group……………………………………………. 23
Selected
varieties ………………………………………………….26
References cited ………………………………………..............30
3
HISTORY,
CULTURE, AND VARIETIES
OF SUMMER-FLOWERING
PHLOXES
A.M.S.Pridham
All the Phlox species, with the exception of Phlox siberica, are native to
The purpose
of this bulletin is to discuss the history, culture, and popular varieties of
the summer-flowering phloxes. The characteristics and native habitat of the
spring-flowering group are summarized briefly from the recent publications of
Wherry (1929, 1930, 1931). The successful cultivation of these early-flowering
phloxes, in either the rock garden or the native garden, depends on rather
strict adherence to the soil and light conditions of the native habitat. With
the exception of Phlox divaricata and
Phlox subulata, there are very few
horticultural varieties of the
spring-flowering species.
Phlox drummondii, the best-known of the
annual phloxes, has been cultivated for about a century. It is a very satisfactory plant,
both in the garden and as a cut flower. There are many types and varieties of
this species.
BOTANY OF THE PHLOX
Phlox belongs
to the Polemoniaceae (Polemonium family), of which Gilia and Polemonium are
other well-known members. The genus is distinguished by the salver-form corolla, slender calyx,
and opposite, entire leaves. Bailey (1924) describes Phlox as
follows:
About
50 annual and perennial temp.-region herbs, sometimes woody at base, with showy
fls. of fhe blue, purple, pink, and crimson series, frequently white, of which
one is Siberian and the others N. American.- Sometimes cespitose: lvs. opposite
or the upper ones infrequently alternate, entire; fls. cymose, paniculate or thyrsoid; calyx narrow,
prominently toothed or lobed, becoming distended and at length burst by the
maturing fr.;
BOTANICAL
DESCRIPTION OF EARLY-FLOWERING SPECIES
Werry grouped
the early-flowering species into three sections: Subulatae (P. nivalis, P. subulata, and P. bifida),
Divaricatae (P. divaricata, P. pilosa, and P. amoena), and Ovatae (P. stolonifera,
P. ovata, P. Carolina, P. glaberrima,
and P. maculate). The following
descriptions are taken mainly from his publications.
Section Subulatae
“Members are
characterized by having woody, trailing-decumbents stems, narrow persistent
leaves, and cymes of few rather long-pedicelled flowers.” – Wherry, 1929.
4
Fhlox nivalis Loddiges was listed by
Plukenet (1696) as "Lychnidaea Blattariae accedens Virginiana minor,
repens hirsutis Camphoratae foliis, floribus fistulosis in Umbellam
sitis." It is native as far north as southern Virginia, and is not
entirely hardy in the northeastern part of the United States. It is typically
an inhabitant of dry, thin, oak or pine woods where the soil is commonly a
mixture of sand and clay often rich in humus. This species is seldom cultivated.
Phlox sabulata Linne (moss pink) was
listed by Plukenet (1696) as "Lychnidaea Blattariae accedens Virginiana,
Camphoratae congeneris glabris foliis, flore ad summitatem ramulorum
singulari." It occurs through the coastal
plain, northward from western
The
characteristic habitat of P. sabulata
is a bare sunny slope where the soil is sandy or gravelly and rock ledges lie
near the surface. Humus
may be present in considerable amounts, but often is lacking. Moisture
is usually very scant.
The earliest
record of the introduction of P. subulata
is contained in a letter from John Bartram to Peter Collinson dated
[Figure 1. PHLOX SUBULATA. AN EXELLENT
VARIETY
FOR THE NATIVE, OR WILD, GARDEN, AND ALSO
FOR
THE ROCK GARDEN]
sod of the fine creeping spring Lychnis" was
mentioned. As time went on, varieties of P.
subulata appeared on the market, such as Nelsonii originated by Nelson about 1852 (Nelson, 1872). P. subulate vivid, a bright-colored and
luxuriant variant of the species itself, and the variety G.F. Wilson which is intermediate between P. subulata and P. bifida,
are two of the best. There is also a lilac-colored form. All are excellent
material for the rock garden (McCully, 1927: Anonymous, 1931) and may also be
used for forcing indoors during the winter (Russel, 1841).
Phlox
bifida Beck (sand phlox) is native west of the
5
In spite
of the attractive aspect of most of its variants, P. bifida has not been cultivated to any extent. It deserves
more attention from
horticulturists.
Section Divaricatae
"Its
members differ from those of the former section in that the stems are scarcely
if at all woody, the leaves axe fewer, larger, and less persistent, and the
inflorescence is a more compound cyme of short-pedicelled flowers; in these the
sepals are united for 1/3 to 1/2 their
length, and the stamens and styles are much shorter than the corolla-tube. The
western species included in the section by Peter are not treated here, but four
eastern ones are recognized. In the following synopsis these are arranged in
the order of increasing compactness of inflorescence."—Wherry, 1930.
Phlox divaricata Linne (blue phlox) was
discovered in the early colonial days and was listed by Plukenet (1700) as
"Lychnidea Virginiana Blattariae
accedens, Alsines aquaticae foliis, floribus summo caule brachiatis, sive in
ramulos divaricatis." The earliest reference to its introduction to
horticulture is contained in the catalog (Dillwyn, 1843) of Peter Collinson's
garden: "A very pale blue early Lychnidea, in flower
P. divaricata is one of the most
wide-ranging of all the species, occurring from western
The
horticultural value of this phlox is well known, many dealers now listing it
under various combinations of the names divaricata,
canadensis, laphami, and so forth. The variety with violet (blue) entire-lobed
corollas (P. divaricata laphami) is a
very showy plant and especially vigorous.
P. divaricata has been used as one of
the parents of a series of hybrids originated by George Arends, of
Phlox pilosa Linne
(downy phlox) was listed by Plukenet (1696) as "Lychnidaea umbellifera
Blatteriae accedens Virginiana major, repens, Pseudo-melanthii foliis pilosis,
flore albo, pentapetaloide, fistuloso." It has a range extending farther
west and northwest than that of P.
divaricata, but not so far northeast. The plant grows in many habitats, but seldom thrives in
the rich soils of gardens.
Phlox
amoena Sims (Sims, 1810) has a rather restricted range—from
6
[Figure 2. PHLOX DIVARICATA. AN ATTRACTIVE
VARIETY FOR
PLANTING IN THE NATIVE, OR WILD, GARDEN
AND IN THE
ROCK GARDEN]
Section Ovatae
“Differs from the one next preceding in that the sepals are usualy
united to half their length or more, and the stamens and style are nearly or
quite as long as the corolla-tube."—Wherry, 1931.
Phlox
stolonifera Sims (creeping phlox), discovered by John Fraser in 1786,
ranges from
Phlox ovata Linne (mountain phlox)
was listed by Plukenet (1700) as "Lychnidea fistulosa Marilandica, Clinopodii
vulgaris folio flore amplо
singulari." It is essentially a southern-Appalachian plant but ranges
within the glaciated
The showy flowers early attracted the attention of the horticulturists,
and Sims (1801) states that the plant was common in English gardens before 1801.
The species is not very long-lived in rich garden soils, but it is well suited
for wild areas where the soil is sterile and acid.
Phlox
7
various
intermediates betwen P. ovata, P.
glaberrima, and P. maculata to which many different names have been given.
P.
Phlox glaberrima Linne (Dillenius, 1732) (smooth-leaf phlox) is
native to
Phlох maculata Linne (spotted-stemmed phlox) is recorded as early as 1731 (Miller,
1807), and is listed by Ventenat (1804) as P.
suaveolens, which appears to be the early horticultural name of this
phlox. P. maculata is not cultivated extensively in American gardens. It
is native to the region from
BOTANICAL
DESCRIPTION OF PHLOX PANICULATA
Section Paniculatae is described as follows by Wherry (1933): "Its
distinctive features comprise wholly deciduous foliage, relatively large leaves
with prominent areolate veins and minutely hispid-serrulate margins, a compound
corymbose-paniculate inflorescence, whitish anthers, and styles equalling or
exceeding the corolla-tube."
Wherry's description of Phlox paniculata Linne is as follows: "Mature
plant 75 to 200 cm. tall, with numerous nodes; leaves tending to be
sub-opposite, narrow to moderately broad, their surfaces glabrous to pubescent
but rarely coarse-bristly; inflorescence more or less pubescent but infrequently
glandular; corolla-tube often pubescent; one or more anthers exserted."
Phlox amplifolia Britton has been
regarded by some botanists as a synonym of P.
paniculata. Wherry considers it sufficiently different to deserve
independent status. The mature plants are not so tall nor so vigorous as those
of P. paniculata, and are rarely cultivated.
P. paniculata was imported from
In 1812, one Mr. Lyons, of
During the early part of the nineteenth century a number of nurserymen
imported P. paniculata, each
applying a new name to the species. Thus, in 1823, David Cameron, gardener to
Robert Barclay of
8
the name P.
Sickmani and P. Americana. The form P.
scabra
HISTORY OF THE PHLOX
THE FIRST HYBRIDS
The commercial importation of phloxes to
In 1740, Bartram (Darlington, 1849:137) refers to "the Lychnis with
crosswort leaves" (P. panculala). In 1743, in reply to Collinson's
praise of a plant in the
Our swamps and low grounds are full of them. I had so contemptible an
opinion of it, as not to think it worth sending, nor afford it room in my
garden; . . . The other, which I brought from Virginia, grows with me about
five feet high, bearing large spikes of different coloured flowers, for three
or four months in the year, exceedingly beautiful. I have another wild one,
finely speckled, and striped with red upon a white ground, and a red eye in the
middle—the only one I ever saw.
In the notes which Collinson made of the plants in his garden, little
regard was paid to botany. But after his death, these notes were used by
Dillwyn as the basis for his Hortus Collinsonianus, the following extracts
from which are pertinent (Dillwyn, 1843) :
Phlox paniculata. "Lychnidea fol.
Persica, flo. in spicam depositis." "1744 a new Lychnidea, sent by J.
Bartram, with a large spike of pale reddish purple flowers, with peach-shaped
leaves, flowered in July and August, called in Virginia Sawpit flower."
Phlox paniculata Var.? Not in catalogue. "Flowered in my
garden
From the above it is evident
that hybrids of P. paniculata were to be found in nature, and this may account
for some of the synonymy whicn existed during the early nineteenth century.
Probably the first hybrids to be raised under cultivation were of P.
paniculuta. Shephardii, introduced by S. Shephard of Bedford, and Wheelerii,
introduced bi G. Wheeler of Warminster were both grown as early as 1824.
The varieties Wheelerii elegans and Wheelerii latifolia were
common by 1837. In 1827, Dickson & Co., of
One of the best-known hybrids of the time was P. coldryana, raised
before 1835 by Mr. Coldry, of the Bristol Nursery (Paxton, 1840). The
9
parentage of this phlox is uncertain, but P. paniculata (P. cordata) has been suggested as one of the
parents.
Other varieties of P. paniculata raised
during this period were P. cordata grandifiora (Clark, of East Redford),
P. cordata ingrami (John Ingram, of
Southampton), P. Bridgesii (C. J. & P. Young, of Epsom) named
in honor of Lady Bridges, and P. cordata omniflora (England), which was said
to be as hardy as an oak and of which there were several horticultural forms. Lorrainii
and Murrayana might be mentioned also.
Not all of the phlox hybrids popular on the
Continent were of English origin. M. Lemon offered the varieties grandiflora,
fragrans, and superba before 1832, and M. Souchet, of
THE SUFFRUTICOSA
VARIETIES
During the latter part of the decade
1830-40, a group of phlox hybrids of P.
maculate (P. suaveolens), a kind
with white blooms placed in a pyramidal form, and P. carolina, a kind
with purple-red well-marked florets, became
very popular. The progeny of the cross is described as having been dwarf in
habit, with beautifully rounded and usually two-colored florets in large
crowded panicles; the foliage was of shining lanceolate leaves, more or less
broad. Subsequent generations approached the paternal characteristics more
closely than the maternal.
M. Rodigas, professor at the Ecole d'Horticole de l'Etat a Gendburghe les Gand, was an
associate of Louis Van Houtte and a specialist in phloxes. Van Houlte purchased
from Rodigas a seedling of the parentage described above. The price paid was
1200 francs (Jonghe, 1845), and the seedling was disseminated under the name Van
Houttei. This phlox received both horticultural and botanical recognition,
and was soon widely grown throughout
The effect of Van Houtte's purchase was to stimulate the naming of phlox
seedlings and to encourage many growers to turn their attention to phlox. The
variety Van Houttei was not always popular; one writer (Anonymous, 1842)
stated that it was not superior to nor more popular than the variety Princesse
Marianne (introduced by Mme. Van Gavers, of
Hovey (1849) described Rodigas as the greatest of all phlox-breeders,
and stated that he raised more than thirty thousand seedlings. Definite record
is available of more than seventy, the most important of which are Van
Houttei, Rodigasii, and Leopoldiana. The last-named variety is
recorded as the first cross between P. drummondii, the annual phlox, and
a variety of the perennial type, in this case probably Van Houttei (Anonymous.
1849).
THE
DECUSSATA VARIETIES
By 1850 it was apparent that the suffruticosa
hybrids, in spite of their beauty of color, size of panicle, and continuous
habit of flowering, were not suitable subjects for the average garden. The
original type was of a somewhat tender nature, suffering from both the summer's
heat and the winter's cold, and most of the varieties grew poorly on sandy
soils.
10
Interest soon turned to P. paniculata (P. decussata, P. acuminata), as
this species and its derivatives were very vigorous and perfectly hardy. The
French were particularly interested in P. panculata hybrids, and at the
Exposition des Produits de l'Agriculture et de l’Industrie in Paris (Baudement,
1849) the phlox exhibits of M. Pele, M. Lierval, and M. Chauviere received
special mention.
The interest in the decussata group was due to the efforts of
Lierval, who, as a young man, took up the breeding of phloxes in 1839. His aim
was the improvement of the decussata group, which he describes as
follows (Lierval, 1866). The quotations are translated from the original
French.
At the time of its introduction, P. decussata showed the
following characteristics: Stems 35-49 cm. in height, rather slender, straight,
and upright, covered with a fine down, angular, the angles rounded. Leaves
opposite and placed crosswise, oval lanceolate,
narrowed at the base and slightly petioled, narrowed and long-pointed at the
top, finely downy on the under surface, creased in the center at the point of
insertion. Flowers red, more or less
varied with clear or shaded purple, placed in corymb-like loose panicles, calyx
finely downy on the outside with five narrow and pointed sepals.
Lierval claims to have increased the size of the corolla, enlarged its
lobes, and produced a more rounded floret; to have procured infinite variation
in color; and to have enlarged and elongated the panicles. He describes the
ideal phlox as follows:
1.
The inflorescence
The panicle should be rather more elongatedthan flat. In flat panicles
the lower branches elongate to the detriment of the center of the panicle,
which completes its flowering before the lower branches have begun to flower,
hence leaving the center open. Flongated panicles do not have this fault, and
only those corymb-like-panicled varieties which flower perfectly should be
encouraged.
2.
The form of the
corolla
The ideal corolla is perfectly round and
the individual lobes overlap one another. Cup-shaped corollas are not
desirable.
3.
Color
a. Pure white; the corolla should be pure white, alsothe tube, for if it
shows the least shade of violet the corolla will become colored as it fades.
b. White as a ground color; in this group the corolla should be pure
white except for the eye, which is very sharply defined.
4.
Other shades
The dark colors are very popular and new shades are much sought after.
Lierval claims the distinction of having originated the type “white with
sharply defined eye,” and states that those white varieties in which the color
is diffused over the floret were very popular.
Many growers introduced varieties during the period from 1850 to 1860.
M. Dufois gained prominence through his variety Rive D’Amour, and M.
Dubus through P. Criterion (Van Houtte, 1852-55), a hybrid between the
perennial type P. depressa and the annual P. drummondii Sanberg,
gardener to Baron Van Heeckeren van Wassenaar, introduced Triomphe de
Twickel (Van Houtte, 1857), which was noted as the most blotched of all
phloxes. Messrs. Downie and Laird, of
11
[Figure 3.
THE FLAT PANICLE OF THE VARIETY B. COMTE]
[Figure 4.
THE PYRAMIDAL PANICLE OF THE VARIETY VIKING]
[Figure 2.
A GLOBOSE PANICLE TYPICAL OF A YOUNG SHOOT, VARYETY MRS. ETHEL PRITCHARD]
12
The varieties raised between 1840 and 1875
which are still in the trade are listed in table 1.
TABLE 1. PHLOX VARIETIES ORIGINATED FROM
1840 TO 1875 WHICH
|
Variety |
Originator |
Data |
|
Adonis |
Rendatler |
1868 |
|
Amphytrion |
Rodigas |
1845 |
|
Belle Pyramid |
Rendatler |
1868 |
|
Bicolor |
Rodigas |
1848 |
|
Brilliant |
Fontaine |
1859 |
|
Crepuscule |
Fontaine |
1853 |
|
Diana |
Rendatler |
1857 |
|
Dugueschlin |
Lemoine |
1863 |
|
Enchantress |
Unknown |
1859 |
|
Exquisite |
Ellwanger & Barry |
1867 |
|
Fernand Cortez |
Lierval |
1863 |
|
Goethe van Houtte |
Rodigas |
1847 |
|
Jeanne d’Arc |
Crousse |
1859 |
|
La Candeur |
Lierval |
1862 |
|
L’ Avenir |
Fontaine |
1867 |
|
Magnificence |
Fontaine |
1856 |
|
Mathilda |
Rodigas |
1844 |
|
|
Fontaine |
1858 |
|
Richard Wallace |
Lierval |
1870 |
|
Saison Lierval |
Lierval |
1865 |
DWARF
PERENNIAL PHLOXES
Dwarf varieties were, from the beginning, particularly popular for both pot
and garden culture. Lierval tried to establish this type, and, while there were
some representatives among his varieties, dwarf phloxes were not recognized as
a class till after his unfortunate death in the Franco-Prussian War (Anonymous,
1871), when interest in phloxes shifted to the south of
M. Chretien,
head gardener at the Parc de Tete d'Or, is credited by Carriere and Andre
(1889) with the origination of the dwarf perennial type of phlox. The type is
described as being dwarf without being pinched back or being grown in pots.
Propagation was effected by making cuttings of the woody section of the stem
next to the base of the plant. The cuttings were taken in the fall of the year
and were heeled in as are rose cuttings over winter, to be potted in the
spring.
Lemoine met the demand for dwarf phlox by creating a race of suffruticosa
varieties which could be treated as annuals (Vilmorin, 1902). The seeds
were planted in the fall and the seedlings were transplanted in the spring to
the desired location. They began to bloom in July and continued till frost in
October.
In 1875, M. Crozy, of
Among other varieties which excited admiration, Comtesse de Jarnac was
the most important. This variety is recorded by Rudolph (1901) as a sport
derived in 1890 by M. Lacour, of Domaine de Conde, who found it growing as a
branch of a named variety. The foliage
was variegated
13
with white blotches, and the flowers were
of a rose color. The plant did not grow over 25 centimeters in height. The
variety Ferdinand Lahaye (Anonymous, 1901) also was prized as a dwarf
mottled variety obtained by chance in the
HISTORY
OF PHLOXES IN
The initial plantings of phlox in
Following the period of importation of phlox species to
European hybrids were imported by American nurserymen as early as 1820.
Prince (1823), Buist (1854), and Hovey (1846) were among the leaders. Joseph Вreck (1851) and William Carter raised and introduced seedlings of P.
panculata as early as 1837, and by 1850 Breck had raised several thousand
seedlings of which about fifty were introduced into the trade. Of these early
introductions, Breckii (Breck), Frelinghuysen (Carter), Henry
Clay (Carter), and Perfection (Breck) were the most important.
In 1844 the Massachusetts Horticultural Society (Hovey, 1844) made its
first special award for seedling phloxes. Frelinghuysen (Carter) won the
first premium, $3, and Estella (
European varieties have always played the greater role in the American
trade, although the American varieties R. P. Struthers (Rea), Riverton
Jewel (Dreer), and Debs, Maid
The majority of the foreign varieties in the present American trade are
from Lemoine, Pfitzer, Ruys, Goos & Koenemann, Arends, Jones, and
Aldersey.
14
CULTURE OF THE PHLOX
DESCRIPTION OF THE PLANT
The phlox is a typical herbaceous plant, the
stems dying down to the ground each fall. There are no definite storage organs,
as in the peony, the delphinium, and the dahlia. The base of the stem is woody,
and the fusion of a number of stems forms a crown from which a large number of
stolon-like roots arise. These roots are produced in the fall, shortly after
the flowering season. They are composed of two distinct regions: an outer
cortex, prominent in young roots and covered with numerous downy root hairs, but
reduced to a barky covering in old roots; and an inner stele from which all
root branches arise. The individual roots are sparsely branched except near the
tip. The root area is extended by elongation of prevailing roots and production
of numerous new roots at the crown of the plant. While roots may extend 2 feet
or more from the crown, they are seldom more than 6 to 8 inches below the
surface of the soil.
Phlox has always been noted as a voracious feeder, requiring soil rich
in organic matter and slightly acid. Light also is important, and, while the
plants will tolerate a moderate amount of shade, best results are obtained from
plantings fully exposed to the sun.
HORTICULTURAL
VALUE
Phloxes may be used to form a border, as individual groups, in plantings
with other perennials, or in beds for mass effect. It is possible also to
cultivate phloxes in pots (Taylor, 1842; Downie, 1856; Smith, 1857; Dybowski,
1889), for use as specimen plants on the porch or for use in porch baskets; for
such purposes, dwarf or semi-dwarf varieties should be selected. Phloxes are
occasionally used as cut flowers, but, with the exception of the variety Miss
Lingard, they are seldom cultivated for this purpose. The French used them as
cut flowers for the Fete de Marie on August 15 (Mottet, 1895). Their chief
value is to furnish an abundance of brilliant color in the garden during the
latter part of the summer, when the majority of flowers have passed their
season of bloom.
PREPARATION
OF THE SOIL
In planting phloxes, care should be taken to
thoroughly enrich the soil with decayed organic matter and to bring it to an
exellent state of tilth.
The site selected for the planting should be in the open sunlight and at a sufficient distance (3
to 6 feet) from other perennials and from shrubbery to avoid shading the phlox
or depleting the soil of its fertility. Planting can be done at almost any
season of the year, but fall planting (September), before the new roots have
developed, is the most logical. The plant is thus enabled to become well
established in its new location before winter.
PLANTING
Individual clumps should be set not closer than 3 feet. This distance
seems entirely out of proportion at the time of planting. Growth is rapid, and in two or three years
the planting will be in excellent condition. A hole 5 inches deep is best for
setting the new plants. The roots are
spread
15
well apart, and
the crown of the plant is covered by not more than 1 inch of soil. Firming the
plants into position is important; this enables the roots to rapidly become
established in the soil. After the plants have been set, they should be
thoroughly watered and lightly mulched with strawy manure. This mulch may be
left on during the winter.
CULTIVATION
In the spring,
the straw mulch should be removed and the soil forked over lightly without
disturbing the plants. The organic matter added from the decayed straw helps to
maintain the soil fertility and thus to keep the planting in satisfactory
condition for a long time.
[Figure 6.
YOUNG SHOOTS PINCHED BACK IN ORDER TO FORCE THE PLANT TO FLOWER LATER IN THE
SEASON. The results of
such pinching-back are not always satisfactory and the practice is not
recommended]
16
When the
plants are 18 inches in height they should be dusted with a preparation
containing colloidal sulfur. The dusting should be done every ten days or two
weeks throughout the season. The forceful syringing with a hose at similar
intervals is important also. As the plants reach the flowering stage the bloom
can be greatly improved if the soil is kept well watered. This is particularly
important in dry seasons; but it should he done judiciously at all times, since
excess moisture retards the growth of phloxes and encourages the rapid
development of mildew.
After the
plants have passed their major period of flowering, the panicles should be cut
in order to prevent the production of seed. If such a precaution is not taken,
seedlings develop rapidly and the continuity of the original planting is lost.
After frost has destroyed the tops, the stems should be cut back to the ground,
and, together with the fallen leaves, should be removed from the planting and
burned. This will help to check the prevalence of diseases and insect pests,
and to maintain the planting in a healthy, vigorous condition for a number of
years.
The longevity
of a planting depends not only upon the fertility of the soil and the exposure
to the sun, but also upon the spacing of the groups in the planting. A planting
should be at its best from two to four years after it has been set, and it may
remain in good condition for as long as six years. If the plants lose their
vigor and the flowers their brilliance of color, the clumps should be dug up
and replanted in a fresh location which has been adequately prepared.
Renovation of
a phlox planting may be done in the spring or in the fall. The clump should be
lifted and the soil shaken out as much as possible. The clump can then be
pulled apart, and each stem, with its roots, separated from the others ready
for replanting. Some gardeners merely cut the clump into four or more sections
with a spade; but the above method is preferable, in spite of the additional
labor involved.
The planting
and the care of the replanted phlox are the same as are described above for a
new planting. Diseased plants should, of course, be destroyed, and even in
healthy plants the tops should be cut back, leaving from 6 inches to 1 foot of
stem, and the roots should be cut back to 6 or 8 inches in length.
For further
discussion on the cultivation of phlox, the readeг is referred to Miller (1759),
Cameron (1840), Downie (1855), Harrison (1906), Thayer (1919), Stager (1920?),
and Pridham (1928).
PROPAGATION
Phloxes may be propagated by division of the
clumps as described above, by root
cutting, or by stem cuttings. Layering
is occasionally practiced, but propagation by root cutting is the usual method.
According to Mallinson (1925), root cuttings are best made from
one-year-old plants in November, though the clumps may be lifted in the fall
and kept over winter in a frost-proof cellar or frame and the cuttings taken
earh in the spring. Mallinson describes the process as follows:
The straight fleshy roots should be
chosen and cut off full length , then the bunch of roots should
be cut into about 2-in. lengths. Care should be taken to keep them all right
end up.
Be careful to avoid
any chance of mixtures by using plenty of
17
labels and cleaning up one variely at a
time. When work with each variety is finished, all small pieces of root should
be carefully cleared off the bench.
The cut roots are then heeled in in the frame, upright in rows about 4 in. apart. A good strong label
should be nailed on the frame to mark the first row of each variety, and it is
advisable to leave a blank row between each two varieties, so that you can see
the dividing line distinctly when you dig for planting in spring. The roots,
which can be quite close together in the rows, should be covered by about half
an inch of soil. This should be well
firmed and then mulched with hay, leaves or light manure. After heavy frost has
set in the frame can be covered up for the winter with an additional mulch or a
good covering of meadow hay. It is not necessary to place the sash on the frame
although, if they are at hand, they can be used.
The roots will commence to sprout about the middle of April and the
covering should be removed at the first sign of growth as the young shoots are
very tender and easily broken off. They need plenty of water after they have
started to grow and should never be allowed to dry out. They should not be
planted out until they have made from 4 in. to 6 in. of growth and plenty of roots;
this will probably be about the first week in June, depending on weather
conditions.
They can then be safely planted directly into the field where risk of
loss is lessened if you have a strinkler system available. If possible it is
always best to wait for a dull day on which to plant out.
Stem cuttings are generally used in propagating suffruticosa varieties.
These may be taken in the spring, after the shoots have made a growth of about
3 inches; or the clumps may be lifted in the fall, stored for the winter in a
frost-proof cellar, and forced into growth during early spring. In either case
the cuttings should be trimmed, set in sand, and kept well watered till they
have rooted. The young plants should be potted and allowed to grow for a month
before they are set in the nursery row. They generally make good salable clumps
the first season.
When new varieties of phlox are desired, they must be raised from seed.
One of the easiest ways to isolate plants selected as parents is to grow them
in an isolated location. Individual panicles can be protected from foreign
pollination by inclosing them in silk envelopes as described by Lierval (1866).
According to Flory (1931), the haploid number of chromosomes in phlox
is seven. This holds true both for the various species and for many of the
garden varieties including Elizabeth Campbell, Rheinlander, Mrs. Jenkins, and
R. P. Struthers. Crosses have been effected between the annual phlox, P.
drummondii,1 and the hybrids of P. paniculata. Arends
obtained his hybrids from a cross of P. divaricata with the P.
paniculata hybrids. The variety Leopoldiana, originated by Rodigas,
was recorded as a cross between the annual phlox and a perennial
phlox—presumably Van Houttei, one of the suffruticosa group. P.
Criterion Dubus-Miellez was a cross of P. drummondii with P.
depressa, hardy in
The only genetical information available is that concerning P.
drummondii. Gilbert (1915) and Kelly have reported on the inheritance of
color and floret form. Kelly (1922, 1927, 1929) has reported also on the
inheritance of astylis, fasciation, and doubleness.
The seeds of P. paniculata are thrown from the ripe seed capsule
as it bursts; hence careful watch must be kept of the capsules, or the panicle
_________________
1 Phlox
drummondii, the annual phlox native to
18
should be inclosed in a silk envelope as
suggested by Lierval (1866). The seeds frequently fail to germinate unless they
are planted immediately, so that it is necessary to prepare the seedbed in the
summer before the seeds have ripened.
[Figure 7.
A PHLOX CLUMP WITH THE SEED CAPSULES FORMING. The seed capsules are formed shortly after
flowering of the plant and ripen quickly. At this stage the remains of the
flower heads should be cut off or else inclosed in silk enveloped to save the
seed]
A light sandy soil is the best for the
cultivation of phlox seedlings. The soil should be well watered, and the seed
should be set in shallow trenches and covered lightly with compost. In the
spring the seedings are best transplanted to post as soon as the first leaves
have developed. When the plant have reached a height of 6 or 7 inches they
should be set in
19
[Figure 8.
A CLUMP CUT BACK AFTER FLOWERING TO PREVENT THE SEED FROM RIPENING AND
PRODUSING NEW SEEDLING IN AN ESTABLISHED PLANTING. (This is the clump shown in figure 7)]
the held It is well to select a location
where the soil is especially rich and where the seedling can be watered in case
of dry weather. Many seedling will flower during the first summer. Those which flower
after the first frost cannot be judged as to color for the frost and dry
weather of autumn modify the color and markings of phlox.
In selecting seedlings, a definite standard should be set and all
seedlings that fail to meet this standard should be discarded at once. At the
present time there is a great need for pure white varieties of vigorous,
disease-free, and ever-flowering habit. Good varieties of a pure pink color are
few, and, with the
present interest in rock gardens, varieties of the type of Tapis Blanc and
Jules Sandeau should find a ready market.
DISEASES AND
INSECT PESTS OF PHLOX
Mildew is the commonest disease of phlox, and red spider is the universal
insect pest. Leaf-spot, leaf-blight, nematodes, and phlox plant-bug also are recorded
as diseases and pests of phlox. Detailed descriptions of these troubles and
recommendations for their control are given by Weigel and Middleton (1926),
Cory and McConnell (1927), and White (1931).
While special methods of control are recommended in some cases, it is
generally agreed that strict adherence to the principles of good cultivation
is of primary importance. The tops of the plants should be
20
[Figure 9.
TAPIS BLANC, A DWARF VARIETY OF EXCEPTIONALLY ATTRACTIVE HABIT.
The flower is pure white against deep
green foliage. The variety blooms over a long period and hence is very
desirable for the rock garden]
carefully cut off at the ground in the fall, and
burned at once. Renovation of old plantings, adequate spacing of the plants,
and syringing the foliage with a forceful spray of water once a week, are
important also.
VARIETIES OF PHLOX
THE
SUFFRUTICOSA GROUP
In view of the history of the suffruticosa
hybrids, it seems rather inconsistent that the most popular of all phlox
varieties should belong to this group. The
variety Miss Lingard, originated by Lingard and introduced into
commerce by
21
[Figure 10.
JULES SANDEAU, A MODERN DWARF VARIETY OF A RICH PINK COLOR]
growth is rapid
and vigorous, and the plant is free from disease. Flowering is early (June and
July) and prolific. If the panicles are cut off immediately after flowering, a
second bloom may occur in September. The first bloom is excellent for landscape
effect, or the spikes may be cut and used as cut flowers. Miss Lingard is
one of the few varieties generally used for this purpose. A pink variant of Miss
Lingard has recently been introduced under the name Miss Verboom.
Dr. Hornby is an old but a very worth-while variety. The plants
grow to a height of 18 to 24 inches, and produce an abundance of cylindrical
spikes of pure white florets distinctively marked by a bright crimson eye.
Unlike Miss Lingard, Dr. Hornby frequently sets seed, and it is more
reliable in its habit of fall blooming.
Empress
and Hercules are two other suffruticosa varieties occasionally
found in the trade. They are both mallow purple in color, moderately tall
22
[Figure 11.
MISS LINGARD, THE BEST OUR FEW SUFFRUTICOSA VARIETIES]
in growth, and less prolific than either Miss Lingard or
Dr. Hornby. Hercules is the better variety of the two; its florets are
larger and are more pleasing in color.
23
THE DECUSSATA GROUP
Of the standard varieties in the decussata
group, the following are worthy of note.
B. Comte (introduced by Lemoine in 1900) is a deep rich
purple phlox, of medium height and flowering rather late in the season. It has
been in the trade since about 1904. The panicles are rather flat in form, and the
florets are crowded together and frequently flecked.
Bridesmaid (introducer unknown), a tall, attractive variety, is
one of the most satisfactory in vigor of growth and abundance of exceptionally large
panicles. The florets are white, but the rose eye-color is lightly diffused
over the petals so that in mass plantings the color appears to be a very
delicate rose pink. Bridesmaid has been one of the outstanding varieties
for the past twenty years.
L'Eclaireur (introduced by Forgeot
et Cie. in 1890) (Carriere, 1891) is
rhodamine purple in color, with white markings near the center. The florets are
large and star-shaped. The variety is vigorous, medium in height, and late in
flowering. It has been offered for sale in this country under the name Eclaireur
since 1900.
Elizabeth Campbell (introduced by Pfitzer
in 1909) is of comparatively recent origin and was imported from
Europa (introduced by Pfitzer in 1910) is
a very fine white variety, with a deep, clear-cut, carmine eye. The plants are
of medium height and vigor. The panicles are very attractive.
Frau Anton Buchner (introduced by Pfitzer
in 1907) is large-flowered, pure white, of very pleasing form and color, and
medium in height, it flowers about midseason. While the individual plants are
vigorous, the clumps are usually small, as the variety grows slowly.
General Von Heutz (introduced by Ruys
about 1911) is of similar color to Elisabeth Campbell but is more
brilliant. The florets bear a distinct white marking adjacent to the eye.
Jules Sandeau (introduced by Lemoine
in 1911), first sold in this country about 1927, is one of the finest of the
pink varieties and is of sufficiently dwarf habit for use in the rock garden.
The large individual florets are pure pink, with the reverse side of the petal
a delicate pink. The florets are produced in profusion and over a long period.
The plant is vigorous and forms clumps of moderate size.
La Vague, which was introduced
from
Mrs. E. H. Jenkins (introducer unknown)
is the second most popular variety,
and has been frequently confused with the varieties Frei Fraulein
G. von Lassberg (Pfitzer), Fiancee (Lemoine),
At the time of its introduction into the
American trade (1906), Mrs. Jenkins was listed as tall in habit
of growth; while Frei Fraulein
24
[Figure 12.
ELIZABETH CAMPBELL, ONE OF THE MOST POPULAR SALMON-PINK TO LIGHT SCARLET
VARIETIES]
[Figure 13.
EUROPA, ONE OF THE NEWER WHITE VARIETIES, WHITH A CLEAR-CUT CARMINE EYE.
The plant is vigorous, but not rapid in
growth]
25
G. von Lassberg, introduced in 1895. was listed as medium in height.
[Figure
14. MRS. E.H. JENKINS, A PURE WHITE VARIETY. This is one of the most popular of all phloxes. The
plant is of medium height and is vigorous. The flowers are distinctly
star-shaped]
26
yellowish green about midseason. The
variety fills the need for a vigorous-growing white variety for landscape purposes.
Rheinlander (introduced by Goos
& Koenemann about 1914) is one of the best salmon-pink varieties. The color
is intensified by the deeper color of the eye. The panicles are dense and
globose in shape, and the individual florets are star-shaped. The stem and the
calyx teeth are intensely colored. The variety grows to a medium height,
flowers at midseason, and is of moderate vigor.
R. P. Struthers (introduced by Rea
about 1900) is one of the best-known varieties of American origin. In color it
is a rich rose to salmon-pink, with a deeper eye. Its florets are typically
waved. The plants are vigorous, free-flowering, and tall, and blossom at
midseason. This is one of the most attractive varieties.
Rijnstron (introduced by Pfitzer
in 1910) is rose-salmon in color, and has typically curled florets and a rather
loose panicle. The plants grow to a height of 30 to 36 inches and are
moderately vigorous.
Thor (introduced by Goos &
Koenemann) was first sold in this country in 1915. The color is a rich salmon-pink,
with a deeper eye. The large florets form a dense, pyramid-shaped panicle. The
plants are moderatcly vigorous, are of medium height, and flower a little after
midseason.
Widar (introduced by Goos &
Koenemann about 1912) is purple-violet in color, with a distinct white eye. The
large florets form a dense panicle which tends to be oval in outline. The markings make the variety particularly
interesting.
SELECTED
VARIETIES
Of the many other varieties now in cultivation, the following have been
selected because of their general superiority, their adaptability to some
special use, or their particular interest to gardeners who specialize in plant
novelties.
Annie Cook (introduced by Thurlow
in 1913) is an attractive light lilac-pink, with a deeper amaranth-pink eye.
The florets are of moderate size, and from large, dense panicles which flower
rather late in the season. The plants are vigorous, and are medium to tall in
habit.
Anton Mercier (introduced by Lemoine in
1901) is of semi-dwarf habit of growth. Its interesting phlox-purple florets
are distinctively marked by a white eye. The plant are
Cameron (introduced by Forbes in 1900)
was grown at
Crepuscule (introduced by Fontaine in 1853) is the oldest and best-known
of all phlox varieties. It is often referred to as the mother of our modern
phloxes, and has long been a favorite with phlox-growers. The
27
[Figure
15. RHEINLANDER, ONE OF THE BEST SALMON-PINK VARIETIES]
[Figure
16. WIDAR, A SEMI-DWARF VARIETY, FLOWERS PURPLE-VIOLET WITH A DISTINCT WHITE
EYE]
28
[Figure
17. SALADIN, THE MOST BRILLIANT SCARLET OF THE PHLOXES. The plant is tall and vigorous,
and blooms over a long period]
29
florets are moderatery large, and are of a
peculiar dark lilac color which is shaded lighter toward the edges of the
petals, producing a sivery gray effect. The plant is
Graf Zeppelin (introducer unknown,
1918), only recently found in American gardens, is creamy white with a delicate
rose-pink eye. The large florets and panicle produce a very rich effect. The
plant are tall and
Le Mahdi (introduced by Jones, of
Mrs. Ethel Pritchard (introduced by
Pritchard, of
Mrs. W. G. Harding (introduced bу Schmeiske in 1923) is one of the best of the new phloxes of American
origin. The florets are exceptionally large, and are deep rose-pink with a
deeper eye. The panicles are not large, but they flower continuously throughout
the season. The foliage is of a rich deep green color and of particularly heavy
texture, and the stems are distinctly woody. The variety shows marked advance
in habit of bloom and resistance to disease. The plants are of medium height
and are vigorous. The clumps are large, though the number of stems produced is
below the average.
Richard Wallace (introduced by Lierval
in 1870) is one of the few varieties introduced by Lierval which are still in
the trade. The florets are moderately large, are pure white in color, and have
a deep, clear-cut, crimson eye. The panicles are large and attractive, and the
plants are vigorous.
Reichgraf von Hochberg (introduced by
Pfitzer prior to 1900) is one of the best of the deep red-purple varieties. The
panicles are large and are profusely branched. The variety is vigorous but is
not a rapid grower.
Saladin (introduced by Goos &
Koenemann in 1924) is the deepest and most brilliant of the scarlet
varieties. The florets are large and
well formed, in large, dense, oval-shaped panicles. The plants are tall and vigorous, and the
clumps are large. The color stands out
boldly across the garden and does not fade in the sun.
Tapis Blanc (introduced
by Lemoine in 1901, and later under the name Mia Ruys) is one of the
best of all the phloxes, and one of the most dwarf. The color, a pure rich
white, stands out conspicuously. The florets are large and the variety remains
in bloom throughout the entire season. The foliage is deep green and very
resistant to disease. Tapis Blanc is especially desirable for planting in rock
gardens.
30
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—-----
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—---—
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-------
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-------
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------
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-------
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