by Dr. Juerg Plodeck, Sept.-Dec. 2002
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by Dr. Juerg Plodeck, Sept.-Dec. 2002 |
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published by Hemerocallis Europa in:
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This article is divided into 3 sections: |
Ploidy
Tetraploid daylilies are not present in nature; i.e. this is human made by applying colchicine on the growth point of the fans
or seedlings or meristem cells (colchicine prevents the cell division, which results in doubling the chromosome set).
In nature there are only diploid daylily species, but also a few triploid are known like
H. fulva 'Europa',
H. fulva 'Kwanso',
H. fulva var. maculata and
H. fulva var. angustifolia (as these are triploid they can in principle only be propagated by
division or cell culture; I wonder why some of them got the status of a fulva variety and not of a fulva clone as is with 'Europa' and
'Kwanso', i.e. being named
H. fulva 'Maculata' and
H. fulva 'Angustifolia').
Triploid plants are pretty much sterile, as the reduction segregation (meiosis) to produce pollen and egg cells normally does not
result in appropriate pollen or egg cells consisting of a single or double chromosome set (the chromosomes are sometimes broken in two,
or a cell contains beside the complete set of chromosomes a few extra ones [double] which prevents fertilization or leds to aborts).
Only by chance and many trials you can get pods from the pollen or egg cells of triploid plants.
So the daylily species could only be used to produce diploid cultivars (sometimes daylilies produce unreduced gametes [pollen/egg cells]
which can be used to pollinate tetraploid cultivars).
Roots and Runners
There is probably no cultivar specially hybridised for its roots, as they are hidden in the ground and of no interest so far.
However most cultivars grow in a more or less compact plant, which makes it to a certain degree difficult to divide a plant.
The ability to produce runners a few centimetres away from the mother fan was normally bred out. However for landscaping,
i.e. planting daylilies along a road as it is the case in the USA, this trait is preferred and plants having this trait were more often
used than others in order that the area gets faster covered by the cultivar or species and less plants are needed for the initial
planting. The ability to produce runners more than 20cm away from the mother fan can be found in most if not in all of the
H. fulva species. In addition
H. lilioasphodelus also produces runners, but they normally are around 10cm and seldom get to 20cm
or more. All the other species seldom show runners and if so, they are normally shorter than 10cm. Very compact clumps can be seen on
H. minor .
Leaves
Some cultivars show yellow-green leaves that can be found as well on the
H. fulva species. Others show blue-green leaves most extremely visible on
H. citrina.
Only few cultivars have variegated leaves; this trait can be found at
H. fulva 'Kwanso Variegata'. As this species is triploid it is not so easy to get seeds from the
few pollen and egg cells that are capable to produce seeds. Probably this trait is not directly to be found in the genes but rather
outside of the nucleus i.e. it will not be transferred via pollen but with the egg cells. This, and because variegated plants can
loose the variegation over time, is probably the reason why there are not many variegated daylily cultivars on the market.
Recently I found 2 small variegated fans beside a mother plant without variegation, but the mother plant is not
H. fulva 'Kwanso' but another
H. fulva, species that has single flowers and was grown from seeds collected wild in Japan
by a person of a Japanese botanical garden.
There are many cultivars which stay more or less green in winter and they even grow a little bit on warmer days. This
evergreen (non-deciduous) behaviour can only be found in one species namely
H. aurantiaca. However some
H. fulva var. littorea (sometimes also named as
H. aurantiaca var. littorea) remain also green or restart new growth in autumn.
In colder climates these evergreen cultivars are not giving a nice picture in winter and early spring and are sometimes even not full
winter-hardy. Even if they look okay during winter, as soon as they start growing again in spring and there is a cold day
(several degrees below 0° Celsius) they start getting muddy and one has to take care in order not to loose the whole fan or plant.
While most of the cultivars as well as of the species have leaves with a diameter of 1-5cm, there are also some cultivars with
grass-like leaves, which are normally also of lower habit. In order to keep the proportion, the flowers are normally also not
as big as the round and ruffled or the spider ones. These grass-like leaves can be found in
H. minor and
H. graminea but also other species like
H. multiflora,
H. nana or the lost
H. darrowiana and
H. fulva var. angustifolia have rather narrow leaves. But normally the narrow leaves in the
cultivars are coming from
H. minor, as this was extremely used to produce small daylily cultivars.
However it is possible that sometimes a small, grass-leaved cultivar has also
H. multiflora in it for some other traits like e.g. late flowering, many flowers etc.
H. nana was very seldom used in hybridization as it is not everywhere winter-hardy and it is not
easy to get seeds from it.
Scape
The size and stiffness of a scape is of big importance for the whole habit of the plant. How good can a plant be if the scape is too short or
bends too heavily and the flowers are hidden in the foliage or on the ground? This trait of bending scapes, not being able
to carry the large number of flowers and/or fruits comes normally from
H. multiflora. As hybridiser tried to select for stronger scapes, this negative trait is seldom seen on
registered cultivars. Very strong scapes are either coming from
H. fulva's or
H. exaltata. But also the other species have scapes that stand upright even if there are many flowers
and/or fruits. Very tall scapes can only be found on
H. altissima, which is the tallest of all daylily species with a height of up to 2m.
A height of 1-1.5m can be seen on many
H. fulva's but also on
H. citrina and some clones of
H. thunbergii,
H. yezoensis and
H. citrina var. vespertina. Very small scapes have
H. nana and
H. darrowiana, but
H. darrowiana was never used for hybridisation and is lost, while
H. nana is not winter-hardy in cooler climates and does not easily produce seeds,
that is why it is rarely used. Therefore the trait of small scapes in the cultivars is most often coming from
H. minor, but also from some clones of the real
H. dumortieri. All other species have scapes in the range of 40-100cm which can be found on most
cultivars.
Proliferations
Some cultivars show often proliferations while most only seldom or never make this pleasure.
This ability of proliferations is well known for
H. fulva var. littorea, but it also can be seen sometimes on other
H. fulva's like
H. fulva var. sempervirens,
H. fulva 'Kwanso' and other
H. fulva clones. In addition other species like
H. altissima and
H. coreana show sometimes this ability to multiply and occasionally it can also be found on
H. citrina and very seldom on others. Several proliferations I got this year on SPOOKY FINGERS
(Holman, 1991), but it was the first time it flowered for me after having it already for 4 years.
Banching / No. of Flowers
Normally a hybridizer tries not only to have wonderful flowers but also many flowers in order that the flowertime last long.
But in order to have many flowers it is necessary to have a branched scape. The wider it expands the less the flowers hinder themselves,
if open at the same time. Therefore no branching (= one way branching) or two way branching
with only few flowers as can be seen on
H. nana,
H. darrowiana,
H. dumortieri and
H. middendorffii is something one tries to avoid.
To achieve good branching one uses the species with many branches like
H. citrina var. vespertina (7 way branching),
H. multiflora and
H. altissima (6 way branching), or
H. citrina,
H. yezoensis and
H. hakuunensis (5 way branching). All of the species with 5-7 way branching show also a great
number of flowers per scape except of
H. hakuunensis (having only 6-11 flowers per scape). With the exception of
H. multiflora, the scapes of the many branched Hemerocallis species are strong enough
to hold the weight of the flowers and fruits. Also
H. multiflora having this disadvantage compared with the others, it also has a bonus,
namely longer pedicels which gives a more loose impression and no overlapping of flowers on the same scape.
This influence can be e.g. seen on THUMBELINA (Fischer, 1954).
On some species like
H. citrina var. vespertina,
H. multiflora,
H. coreana and
H. fulva var. sempervirens more than 100 flowers per scape were already observed.
This number is exceptionel and probably not only condition but also clone dependent.
Flowers
The flower season of most cultivars is in summer, i.e. in July.
This is also the month during which most of the species flower. For extending the flower season to start earlier, crosses with the
very early
H. minor,
H. lilioasphodelus but also
H. dumortieri and
H. middendorffii were made, as these start to open their first flower in May.
More seldom the early flowering
H. nana and
H. plicata were used in hybridizing. But also to enlarge the flower period until autumn some
late-flowering species were used, namely
H. altissima (August),
H. multiflora (August-September) and
H. fulva var. sempervirens (end of August-October).
The ideal would be a cultivar starting to flower in May and ending in October when the first frost comes.
In order to achieve this, many different crosses were necessary, involving not only species with early and late flower season,
but also species known for their ability of reblooming like
H. middendorffii and to a even lesser degree
H. lilioasphodelus and
H. minor. They may have helped to get to this goal which was first achieved in STELLA DE ORO
(Jablonsky, 1975).
But not only the flower season is of importance but also the flower duration.
As the name Hemerocallis and Daylily state, it is a beautiful flower for one day.
However there is especially one species known with an extended flower duration, namely the flowers of
H. lilioasphodelus being open between 36-48 hours. The very close related
H. minor brings it to 24 hours. This means that they are open during the day and the night and
as most night-flowering plants, the flowers are of a bright colour (namely yellow) and odorous.
All other species have a shorter flower duration. Its flowertime is either nocturnal
(opening in the late afternoon and closing in the morning) like
H. citrina,
H. altissima,
H. yezoensis or diurnal (opening in the morning and closing in the late afternoon) like
H. fulva,
H. middendorffii, and many more.
The flower size is another character which is of some importance.
Small flowers are normally welcome on smaller plants getting only to a height of up to 40cm.
On these miniatures a large flower would not be in proportion to the plant size, and the overall impression would be a little bit strange.
Smaller flowers mostly in trumpet shape can be found on
H. minor,
H. lilioasphodelus,
H. darrowiana,
H. nana and
H. multiflora. On a tall plant one normally likes to have larger flowers, however smaller flowers
may also look nice if many are open at the same time, but distributed over height and width as is to a certain degree the case with
H. multiflora, especially if there are many scapes around (the only problem is that the scapes of
H. multiflora are only upright when they start to flower and later they bend more and more towards the ground).
Larger flowers are present in
H. fulva's,
H. aurantiaca and especially in
H. citrina (but the last is a spider, nocturnal and as the form is a trumpet, it does not open very wide).
The number of segments (tepals) for daylily species is normally 6,
i.e. most Hemerocallis species have single flowers. But there are three
H. fulva clones with double flowers, namely
H. fulva 'Kwanso',
H. fulva 'Kwanso Variegata' and
H. fulva 'Flore Pleno'.
H. fulva 'Kwanso' and its variegated form are triploid and it is rare to get seeds from its pollen
or egg cells. The pistil as well as the anthers are normally reverted back to tepals but there is still some pollen produced on it.
H. fulva 'Flore Pleno' is normally sterile as there is no pollen or pistil visible, but up to eighteen tepals.
The double cultivars probably come from
H. fulva 'Kwanso'. Meanwhile there are also polytepal cultivars available that show not only
occasionally 8 or 10 tepals but have more than 50% polytepalous flowers like e.g. DEMPSEY FOURSOME (Dempsey, 1992), I’M DIFFERENT
(Beckham, 1981), FOUR STAR (Kropf-Tankesley-Clarke, 1988), STARRY DAY (Adams-Adams, 1991), TETRAD (Winniford E., 1982) and
CENTENNIAL GAMBLER’S DREAM (Crawford, 1998). Polytepals not only have 4 or 5 (seldom 6 or 7) sepals but normally also the same amount
of petals, anthers and stigma lobes. Hemerocallis species may occasionally also show polytepalous flowers (I have already seen one on
H. lilioasphodelus and on a
H. fulva species as well as on a unnamed species).
As just mentioned the flower form can be different. On one hand there is the destinction between
trumpet or cup shape and flat or recurved shape.
Trumpete shape can be found on all species belonging to the
H. citrina group, namely
H. citrina,
H. citrina var. vespertina,
H. yezoensis,
H. thunbergii,
H. lilioasphodelus,
H. minor. Recurved sepals and to a lesser degree recurved petals are well expressed on
H. fulva and
H. aurantiaca, but this is also visible to some extend on
H. coreana. To a certain degree flat are on warm days the flowers of some species belonging to the
H. middendorffii group, namely
H. esculenta,
H. exaltata and the reblooms of
H. middendorffii. On the other hand one destinguishes between spiders (ratio of petal width to petal length is 1:5
or bigger), spider variants (ratio between 1:4 and 1:5) and others with broader petals. In principle only
H. citrina can be called a spider, but there are also clones of
H. exaltata with spider qualities (but there are also clones of it that even do not belong to the spider variant class).
As spider variant one finds
H. yezoensis,
H. fulva var. rosea,
H. fulva var. disticha,
H. fulva var. littorea,
H. nana and
H. micrantha; but there are also some other species having clones that make it into the spider variant class.
The broadest petals can be found on some
H. fulva's especially on
H. fulva var. maculata, on
H. middendorffii and according to literature with up to 4cm on
H. esculenta and
H. forrestii. However I have never seen any species petals to get nearly as broad.
Comparing the flower colours of the cultivars with the flower colours of the species one is
surprised of the many different colours. The Hemerocallis species mostly show either yellow, yellow-orange or
fulvous-orange colours. However there is one species called
H. fulva var. roseawith a rose colour, that probably is the source for violet colours
in daylilies. But which species provided the red coloring and where does the near white coming from? The red colour was firstly
achieved on the daylily cultivar THERON (Stout, 1934). A.B. Stout crossed
H. fulva 'Europa' with
H. lilioasphodelus,
H. aurantiaca with
H. thunbergii and
H. lilioasphodelus with
H. aurantiaca. The seedlings he crossed with each other or with
H. fulva 'Europa'. Only eight selection seedlings were involved in order to get a dark red mahagony cultivar.
This colour comes from
H. aurantiaca and
H. fulva 'Europa', while the intensification is probably from the other two involved species
(even being triploid
H. fulva 'Europa' led to a few seeds after many thousend pollinations). The near white colours either evolved from
H. fulva var. rosea and/or species like
H. citrina,
H. altissima and
H. thunbergii. The throat of the species is in many cases yellow, but especially in
H. thunbergii and
H. citrina it is green.
Beside the flower colour another important factor concerning the look of a bloom are
patterns like eyes, halos, watermarks, margins/edges, median stripes, nerves, dotting.
Eyes are only present in
H. aurantiaca and
H. fulva's and its varieties. The eyes or more prominent in
H. fulva's than in
H. aurantiaca. As halos and watermarks are a kind of bright (chalky) eyes,
they also have their origin in the
H. fulva's and
H. aurantiaca. Margins/edges probably evolved from the whitening margins on very warm days on
H. fulva var. rosea, but also the other
H. fulva's show to a certain degree a difference in the margin colour.
Wavy margins, which resulted after a lot of breeding in ruffling can be found in
H. fulva's,
H. aurantiaca,
H. thunbergii and many others, especially under warmer temperatures. The
teeth on the tepals are maybe a further development from the strong ruffling and the wavy margins.
Older tetraploid cultivars with teeth are e.g. GREEN FRINGE (Fay, 1974), CREEPY CRAWLER (Hite, 1973) and HEAVENLY CROWN
(Reckamp-Klehm, 1979). As these cultivars are yellow to yellow-orange (HEAVENLY CROWN with rose touch) and have no sign of eye,
H. fulva and
H. aurantiaca are probably not in its ancestry resp. responsible for the teeth.
All these three mentioned cultivars have the tetraploid CRESTWOOD ANN (Fay-Griesbach, 1961) in the family tree.
Their flower forms resemble
H. coreana. Median stripes have also its main origin in
H. fulva's and
H. aurantiaca, but a touch of median stripe can also be found on
H. citrina and some others. The median stripes on the species are normally brighter than
the base colour of the bloom which makes it difficult to see it on bright yellow flowering species like
H. citrina. Nerves are only prominent on
H. fulva's. Where the dotting comes from is not quite clear but probably it comes from the fulvous overlay of
H. fulva and
H. aurantiaca. Another kind of pattern are the characteristics of bitone and bicolour.
Also this comes from
H. fulva's. The above listed patterns make it clear that most of them come from either
H. fulva and/or
H. aurantiaca. All the other species are self; some of them have a green throat and/or a touch of a median stripe.
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e-mail: jplodeck@yahoo.de
