Ornamental Plants
The Garden
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A garden is a place to grow fruits and vegetables, medicinal
herbs, and ornamental plants. Historically, most gardens have
been used for all these purposes at once.
The garden represents an image of paradise on Earth: the
perfect place for peace, relaxation, solitude. The beauty of the
natural world, enhanced and tamed for human use.
– The word “paradise” comes from ancient Persia, meaning “a walled
garden”
– In the Bible, the first humans Adam and Eve lived in the Garden of
Eden.
– The top Google Image search hits for “paradise” are all tropical
beaches!
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Common garden elements: plants, water (fountains, ponds,
waterfalls, streams), shade, sculpture, places to sit, paths.
Elements of design: color, texture, line, and form.
– That about covers my knowledge of design.
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Two main sources of flower and garden knowledge: China and
Japan, and European.
Apollonian vs. Dionysian
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Many aspects of culture can be viewed
through this philosophical concept, which
was first expressed in a well-developed form
by Friedrich Nietszche in his book The Birth
of Tragedy.
The basic idea is that society moves back and
forth between these two poles:
– Apollonian traits: rational, logical, selfcontrolled, ordered civilization
– Dionysian traits: passionate, feeling,
irrational, chaos
Apollo was the god of the Sun, light, truth, and
medicine
Dionysus was the god of wine, insanity, and
ecstasy
In gardening, Apollonian gardens are ordered and
well-kept: everything growing in a designated
position, in careful patterns, well-manicured. A
Dionysian garden lets nature run wild. The two
impulses present in society get reflected in
gardens.
Ancient Gardens
• Ancient Egyptian gardens were surrounded by walls.
The world outside was harsh, dry and too sunny, and
the garden needed to be protected from it. The arid
climate meant that gardens needed constant watering
and attention. Ponds and irrigation ditches were used.
Gardens were laid out in a formal, geometric pattern.
Plants were more similar to wild plants: they hadn’t
had the years of breeding and selection that our
current garden plants have. Trees such as date palms,
figs, and pomegranates provided shade as well as fruit.
• Gardening was popular in ancient Rome, where topiary
was invented: trees pruned to fanciful shapes. Since
many Romans lived in city apartments, window box
gardens were used.
• Gardening was common in the Muslim world. A
common design matched the Garden of Eden: four
waterways linked to a central pool divided the garden
into quarters.
Hanging Gardens of Babylon
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Constructed about 600 BC by King Nebuchdnezzar
to please his homesick wife. She was from Persia,
a more fertile and hilly place than the flat land of
Mesopotamia (modern Iraq).
It was one of the Seven Wonders of the World:
popular places for tourists from ancient Greece
and Rome.
Destroyed an earthquake around 100 AD
Needed to pump water from the river to the top of
the structure.
French Gardens
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The French gardening style was based on
symmetry and order: human dominance
over nature. Geometric patterns and
carefully pruned plants were used.
The Gardens of Versailles reached their peak
under Louis X!V (1638-1715). He was the Sun
King, the center of the European universe at
the height of French power.
– At the center of the garden is the statue of
Apollo, the Greek god of the Sun, symbol of
Louis XIV
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Grand views, extending to the horizon,
contrasted with more intimate perspectives
within the garden: fountains, grottoes,
statues.
The parterre was a common element. A
rectangular planting bed composed of closely
clipped hedges and colored gravel (and
sometimes flowers), in a geometric design.
Masses of color: carpet bedding of flowers.
English Gardens
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The English garden can also be called a
landscape park. It developed in the 1700’s as a
reaction to the formal French style. It presented
an idealized view of the natural world.
Lakes, lawns, gently rolling hills, groves of trees,
classical Greek temples or scenic (fake) ruins.
No symmetry, plants growing into their natural
form. It is designed to appear artless and
uncontrived.
The ideal was blending with nature, so the
garden did not have a visible wall. Sometimes a
ditch was dug and a wall placed at the bottom:
the outside world was kept separate, but the
wall was not visible from the garden.
The cottage garden is the English garden
translated into a style for the middle class. The
design is informal, and it uses dense plantings of
flowers and edible plants. Most modern
American gardens are derived from this style.
Chinese and Japanese Gardens
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Gardening in China is at least as ancient as in Egypt.
Gardens in China sought a naturalistic look, a spiritual
connection with nature and away from the pressures of society.
The garden was the living embodiment of a painting or a poem.
Many plants and objects had symbolic meanings: bamboo is
strong and resilient; pine is long-lived and persistent; lotus
represents purity; peonies symbolize wealth.
Essential elements: a small building with the best view of the
garden, pools of water, a “mountain” with a tree, rocks,
asymmetry
– Especially interesting rocks represented wisdom and immortality,
and could be very expensive.
– Water elements included ponds, streams, and waterfalls. Goldfish
was often in them.
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Plants were essential elements. Some common garden flowers
come from China: chrysanthemum, peony, flowering plum,
roses, camellia. But generally, plants were more valued for
seasonal changes than flowers. These gardens tend to be more
shades of green and brown and not bright colors.
Zen Gardens
• Buddhist monks spread much Chinese culture to Japan
around 600 AD. Japanese gardening modified and
expanded on Chinese ideas.
• Zen Buddhism is based on the idea that one can gain
transcendent wisdom through the practice of
meditation and contemplation, and that written
doctrines are a hindrance to achieving Enlightenment.
Direct experience of the Divine is what is needed, not
common beliefs or rational arguments.
– Zen philosophy originated when the Buddha gave the Flower
Sermon: he sat without speaking, twirling a flower and twinkling
his eyes. Wisdom was communicated to his followers wordlessly.
• Zen gardens are used for contemplation. They are
extremely simple and highly symbolic. Water is
represented by raked gravel or sand. The garden
consists of a few carefully placed rocks or shrubs amidst
the gravel
– Raking the gravel is itself a form of meditation.
Cut Flowers
• Most flowers are sold for big
holidays: Christmas, Mother’s Day
, Valentine’s Day, plus weddings
and funerals.
• There is a great deal of ethnic
group specificity: for instance,
white is the color of death in many
Asian cultures, but it symbolizes
purity in European cultures.
• In Victorian times (roughly 18401910), an elaborate language of
flowers was developed.
• There are two primary flower
arranging traditional: English
Garden and Japanese. These
traditions have become mixed in
contemporary design.
Ikebana
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Traditional Japanese flower arranging got its start with
Buddhist missionaries from China, around 600 AD.
– There are over 3000 Ikebana schools in Japan, with many
different styles and philosophies.
– Much of modern Western flower arranging is based on Ikebana.
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The emphasis is on a minimalist style, with each
element carefully placed and symbolizing some aspect
of the world. Line, shape, and form are emphasized,
with the greens and browns of leaves and wood
important. Usually only a single flower color is used.
The positions, angles, and sizes of various elements
are prescribed.
– Elements often I groups of 3: heaven, earth, humanity; or sun,
moon, earth, etc.
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In this example, the shin branch represents Truth, the
soe branch represents support for the Truth, and the
hikae branch and flowers moderate and balance the
ideas presented in Truth.
– The kenzan is a spiked plant holder.
Some Ikebana Examples
English Flower
Arranging
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The emphasis is on masses of complementary
colors, often with a radially symmetric design. This
is what florists usually produce. Containers are not
emphasized: usually just a simple vase. Foliage is
present as a background feature, but the emphasis
is on brightly colored flowers.
This example is a crescent arrangement. The basic
shape is defined by sprays of small flowering
branches. A group of focus flowers is placed low
and centered to achieve visual balance and
stability. Finally, a group of filler flowers are used
to fill in the shape and taper off the ends.
Modern high style floral design is mixture of
Japanese and English ideas.
Some English Floral Arrangements
Roses
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The rose is probably the most well known and popular
cut flower, and it is also a very popular garden flower.
There are several cultivated species of rose, in the
genus Rosa. Members of the rose family, along with
many common fruits like apples, pears, peaches,
apricots, strawberries and raspberries.
Various species of wild rose are found in temperate
regions of the northern hemisphere, in both the Old
World and the New World.
The basic rose flower has 5 petals and looks much like
an apple blossom. The flowers have many stamens.
Most modern roses are the result of a mutation that
converted the stamens into additional petals.
The fruit of the rose, called the rose hip, grows below
the flower after fertilization. It is a rich source of
vitamin C, but it isn’t eaten as a fruit very much. Rose
hip tea is a common herbal tea variety.
Roses
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Rose cultivation probably began in China 5000 years ago
or so. However, they were also cultivated independently
in the Middle East and Egypt from very early times.
They were well known in the Roman Empire. The first
distilled essential oil was attar of roses (from the Muslim
Golden Age, when distillation was invented).
Europe and western Asia had their own cultivated roses,
which were popular from ancient times. They are
pictured on Egyptian tombs, ancient Greece, and Rome.
Over 250 species, with lots of ability to hybridize
between them. Once a good cultivar is found, it is
propagated vegetatively, through cuttings.
– Growing them from seed allows meiosis and genetic
recombination, giving lots of new variants to work with.
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Useful traits: flowering more than once per season,
disease resistance, vigor, good flowers (appearance and
scent), novelty.
Modern Roses
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Cultivated roses from China were introduced into Europe
in the 1600’s, at about the same time the tulip and other
exotic flowers were introduced into Europe by the Dutch.
At the time, the Dutch were very powerful in oceanic
trade, especially in the spice trade.
• Rose breeding involves the hybridization of many species
and cultivars. It has often been complex and
undocumented.
• Napoleon’s wife, the Empress Josephine, decided to grow
every type of rose in existence, in about 1800. She
gathered many horticulture experts, who did much
hybridization and breeding.
• The first modern rose was ‘La France’, developed in 1867.
It was the first “hybrid tea rose”
– Old Garden roses are types that were present in Europe
before the development of the hybrid tea rose. They have
primarily Mediterranean ancestry (as opposed to Chinese).
They are shades of red, pink and white, with strong scents.
‘La France’, the first
modern rose.
ABC Model of Flower
Development
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What causes modern roses to have so many petals?
Flowers have 4 whorls. From outer to inner: sepals, petals,
stamens, carpels.
When a flower bud gets started, the cells are not clearly
determined to be any particular organ. Which organ each whorl
becomes depends on the expression of 3 groups of genes, called A,
B, and C.
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Cells with only A genes expressed become sepals.
Cells with A and B genes expressed become petals
Cells with B and C genes become stamens
Cells with C only become carpels.
Knocking out any of these genes by mutation alters what happens.
One key finding: A and C genes inhibit each other, and if one is
knocked out, the other spreads to all the cells.
– Knock out A: get a whorl of carpel, stamen, stamen, carpel
– Knock out B: get a whorl of sepal, sepal, carpel, carpel
– Knock out C: get whorl of sepal, petal, petal , sepal.
ABC Model and Double
Flowers
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The main mutation that creates double roses is a
C mutation, but not a complete knockout.
Rather, it shifts the boundary between A and C.
Thus, C is only expressed in a few cells while A is
expressed in many. This gives many petal (the
results of A+B) and few stamens (the results of
B+C).
– This mutation has the additional effect of making
the flower meristem indeterminate: it keeps
producing new flowers inside the old flowers,
resulting in many petals.
• A semi-double flower has more petals than
a single, but it retains many stamens.
• A double flower has few or no stamens, and
must be propagated vegetatively.
Tulips
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Tulips are native to central Asia, places like Afghanistan and
Kazakhistan.
They are monocots, in the lily family.
The flower parts come in groups of 3, like most monocots. In
tulips, the sepals and petals are almost identical, and they get
called tepals for this reason.
They are perennials, storing food over the winter in bulbs and
then sprouting new leaves and a flower stalk every spring.
Bulbs are planted in the fall, and send up leaves and a flower
stalk in the spring. The bulb itself vanishes during this period, but
it gets regenerated after flowering has finished. Also, small
bulblets appear. These can be harvested and replanted. It takes
at least a year of growth for a newly formed bulb to flower.
Tulips can be grown from seed, but it takes 5-8 years before
flowering occurs. And, many varieties are sterile hybrids.
Tulip Breeding
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Tulips have lots of genetic variation, so new varieties
were easy to create.
Like roses and many other garden flowers, tulips have
been hybridized in complex ways between many
species. This means that most tulips are sterile. Tulip
bulbs are vegetatively propagated clones of the original.
– Tulip breeders keep stocks of fertile tulip species, used to
make new hybrids
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Tulips were widely grown in Persia and the Ottoman
Empire. It is the national flower of Turkey.
They were brought to Europe in the 1500’s. The official
beginning of tulips in Holland is 1594. They became
status symbols for the wealthy and socially prominent.
Carolus Clusius, a botanist at the University of Leiden,
popularized tulips and did much crossbreeding. He
founded the Dutch tulip industry. The flowers were so
pretty that people used to steal them from his garden.
Tulipomania
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Holland (aka the Netherlands, home of the Dutch) was probably the richest
country in Europe in the 1600's, due to worldwide trading.
Between 1634 and 1637, tulips in Holland became very expensive. It is the
first recorded speculative bubble. At the height of the bubble, a single tulip
bulb of the one variety sold for ten times the annual wages of a skilled
craftsman. Another single bulb was exchanged for 12 acres of land.
– The main account of tulipomania comes from the book Extraordinary
Popular Delusions and the Madness of Crowds, by Charles Mackay,
published in 1841 and still in print. Like many good stories, this one may
exaggerate the truth a bit. Contemporary accounts are spotty.
Most tulips have a solid color, or a two color scheme. Occasionally, a tulip will
"break": produce a wild color pattern after several years of having a normal
color scheme. This was very popular, the essence of beauty, to the Dutch. The
pattern was inherited through the bulblets, but not the seed. Broken tulips
were slow to reproduce, which contributed to their value.
– We now know tulip breaking is due to a virus infection.
The Dutch invented the futures market. Since tulips can only be dug up and
shipped between June and September, during other months people would bid
on bulbs to delivered in season. They would buy and sell contracts for future
delivery. Most contracts were sold to others, not actually delivered on.
Semper Augustus,
the most expensive
of all tulips.
Speculative Bubbles
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A speculative bubble is when the price of something becomes much
larger than its intrinsic value. With the tulips, the value was purely
aesthetic: they were beautiful, but contributed nothing else of
economic importance.
– The price is inflated, as with air, and a small event can cause the price to
plummet.
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The causes of bubbles are unclear. But, there is a bit of herd
mentality going on: if everyone else thinks tulip bulbs are worth a
lot of money, then they must really be. And, you would be missing
your chance for great wealth if you didn't start buying them right
away! And the price keeps going up, which implies that it will
always keep going up.
The "greater fool" theory: fools buy tulips at inflated prices, but the
price keeps going up as long as they can find greater fools to sell the
tulips to.
Bubbles are the subject of much economic research.
A more recent version: Beanie Babies. Stuffed animals that sold for
$5, but “rare” ones brought huge prices. One that I know of sold for
$2000.
The housing market in the early 2000’s is said to have been a
bubble too.
Orchids
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Orchids may be largest plant family. They are
monocots: parallel leaf veins and flowers with groups of
three. Like tulips, the sepals and petals are similar and
so are called tepals.
– Vanilla is in the orchid family. It is the only “useful”
orchid.
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Most are tropical, but they grow worldwide, in all
climates.
Many orchids are epiphytes: they attach themselves to
tree branches and get their moisture and nutrients
from air, rain, and dust. They are not parasitic on the
tree: they are merely using the tree as a support.
Orchid flowers have many shape variations that cause
them to be interesting horticulturally.
One petal is always enlarged and modified to serve as a
landing platform for the pollinators.
Orchid seeds are extremely small and are produced in
huge quantities. They blow in the wind to distant
locations, carried by tiny wings.
Orchid Pollination
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Orchids are pollinated by insects primarily. Pollination is
rare, but when it happens, millions of seeds are formed.
The pollen grains are glued together in a sticky mass that
sticks to the pollinator's head or abdomen. When the
pollinator reaches a new flower, the pollen mass sticks to
the stigma, the top of the female reproductive parts.
The flowers attract pollinators by interesting mechanisms
first described by Charles Darwin in his book The
Fertilisation of Orchids. (The original title is much longer)
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This was the first book he wrote after The Origin of Species.
The idea of coevolution between the plants and their insect
pollinators comes from this.
• Orchis mascula was Darwin’s model. The two pollen masses
are connected by stalks to adhesive balls that are kept moist
in cups. When an insect sticks its head into the flower to get
to the nectar, the adhesive balls are pulled out of the cup
and stick to the insect’s head. The stalks then rotate the
pollen mass downward, so they match the position of the
female flower parts in the next flower.
Orchid Flower Structure
Coevolution
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Coevolution is the idea that changes in one organism and triggered by changes in
partner organisms.
– For example: Host-parasite interactions: an improvement in the host’s immune system
will lead to selection of traits in the parasite to evade that improvement. (Or, the
parasite will go extinct).
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Plant-pollinator interactions are mutually beneficial. The plant needs to provide a
benefit for the pollinator in return for getting its pollen dispersed. The plant also
needs to attract the pollinator: orchids are especially good at this.
What we see as beauty in flowers is really a mechanism to attract insect
pollinators. Appearance and scent.
– And, attracting humans to propagate them also increases the evolutionary fitness of the
plants.
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Orchid mimicry: the flowers resemble insects sometimes. Pseudocopulation: the
orchid resembles a female pollinator, and the male tries to copulate with “her”.
Pseudoantagonism: the orchid resembles an enemy species, and the pollinator
attacks it.
Others attract pollinators with nectar, or with scents. Some scents are nice and
flowery, or odd things like chocolate or lemon. Other scents are awful, like rotten
meat.
Orchid Mimicry
Bee orchid.
Fly orchid. The two yellow
“eyes” are the pollen masses.
On the basis of an orchid with
A 10 inch nectary, Darwin predicted
(correctly) the existence of a moth
with a corresponding proboscis
Orchid mimic of
praying mantis
Insect proboscis with
several attached
pollen masses
Orchidelirium
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Orchids have been collected since the 1800’s by wealthy
fanatics. “orchidelirium”. They are beautiful and hard to grow.
They grow in exotic locations, so only the wealthy or the
adventurous can afford to acquire them. They became a mark of
wealth and distinction. Orchids are still the subject of massive
collection and breeding efforts. Many are endangered species,
which increases their value.
Orchids are beautiful, with many interesting flower shapes and
unusual scents. There are many species, which often grow in
very limited ranges in exotic locations. They hybridize readily
and sometimes produce new and exciting forms.
– The Orchid Thief, by Susan Orlean, is a non-fictional account of an
orchid collector in Florida. Also Orchid Fever, by Eric Hansen
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It takes 8 months for a seed to germinate, and 7 years from seed
to flower. This gives developers of new hybrids a long window
to make a profit.
Orchids can be easily propagated by tissue culture: growing the
plant cells with hormones, then manipulating the hormone
levels to produce roots and shoots.
Rothschild’s Slipper,
worth $5000 for a
single stem.
Some Orchids
More Orchids