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Propagation of Ornamental Plants
Part I.
By Bodie V. Pennisi, Melvin R. Hall, and John M. Ruter
Department of Horticulture
The University of Georgia
Slide 1. Plant propagation is the creation of new plants from existing ones. Many of us have always
wanted a garden or houseful of plants, but we could never afford more than a few. This
presentation is designed to help you learn about different methods of plant propagation and
help you start your own collection of plants.
Slide 2. Plants can be propagated in two ways: one, by seed or sexual propagation two, vegetatively, or
asexual propagation. A seed carries genes from both parent plants, and appearance of resulting
plants reflects the gene combination. When both parents come from the same species, the
offspring resembles this species. If, however, parents belong to two different species, the
offspring looks like a mixture of the species. This unique appearance results only if the cross is
achieved every time a seed is produced. Hybrid seeds are a result of such crosses. Vegetative
propagation is done by taking a section of one plant and generating a complete replica. The
offspring is identical to the parent because there is no mixing of the gene pools as in seed
propagation. Also with vegetative propagation a larger plant can be obtained in a shorter period
of time.
Slide 3. First let’s look at seed propagation. Seeds are infinite in variety, size, and shape. Orchid seeds
contain over one million seeds in one ounce. In contrast, the Double coconut the world’s largest
known seed, may weigh more than fifteen pounds.
Slide 4. Some seeds germinate readily, and are said to be non-dormant, while others do not germinate,
and are said to be dormant. Seed dormancy is nature's way of setting a time clock that allows
seeds to initiate germination when conditions are normally favorable for germination and
survival of the seedlings. Many trees and shrubs have dormant seeds. Dormancy can be
regulated by the environment or by the seed itself. If a seed is not exposed to sufficient
moisture, proper temperature, oxygen, and for some species light, the seed will not germinate.
In this case, the seed's dormancy is due to unfavorable environmental conditions. In other cases
the hard seed coat that is impervious to water and gases, is the reason for the dormancy. The
seed will not germinate until the seed coat is broken or scratched to make it permeable to water.
This process is known as scarification. In nature, this often occurs by fall seeding.
Slide 5. Scarification also can be forced, rather than waiting for nature to change the seed coats.
Commercial growers scarify seeds by soaking them in concentrated sulfuric acid. Sulfuric acid,
however, can be very dangerous if not used with extreme caution. Vinegar is safer to use. Place
the seeds in a glass container and cover with vinegar. Stir the seeds gently and soak for 10
minutes to several hours, depending on the species. Various reference books provide
information on soaking time. When the seed coat has been thinned, remove the seeds, wash,
and sow.
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Mechanical scarification is another way to weaken the seed coat. File the seed coat with a metal
file, rub with sandpaper, nick with a knife, or crack gently with a hammer. A third method is
hot water scarification. Bring water to a boil, remove the pot from the stove, and place the
seeds into the water. Allow the seeds to soak until the water is at room temperature. Remove
the seeds from the water and sow. Following scarification, the seeds should be dull in
appearance, but not deeply pitted or cracked. Sow as soon as possible because scarified seeds
do not store well.
Slide 6. The second type of seed dormancy is internal dormancy regulated by the inner seed tissues.
Stratification is required to overcome internal dormancy. Cold stratification (moist-prechilling)
involves mixing seeds with an equal volume of a moist medium (sand or peat, for example) in a
closed container and storing them in a refrigerator (approximately 40oF). Periodically, check to
see that the medium is moist but not wet. The length of time it takes to break dormancy varies
with particular species; check reference books to determine the recommended amount of time.
This type of dormancy may be satisfied naturally if seeds are sown outdoors in the fall. Warm
stratification is similar except temperatures are maintained at 68oF to 86oF, depending on the
species.
Slide 7. Here are examples of seed treatments for selected trees. Seeds of some species have a
combination of seed coat and internal dormancy. To germinate, they must first be scarified and
then stratified for the appropriate length of time. If the treatments are done in reverse order, the
seeds will not germinate.
Slide 8. Seed germination of non-dormant seeds is relatively easy, provided the seeds are given their
minimum requirements of air, moisture, and temperature.
Slide 9. This table lists the light requirements for germination of selected herbaceous ornamental plants.
Some species require light, some need dark, and others germinate under either light or dark
conditions.
Slide 10. Many herbaceous plants in the home garden can be easily propagated from seeds. Examples
are: Amaryllis, which has black papery seeds… The hybrid Amaryllis seeds, however, will not
come true to type when propagated from seeds.
Slide 11. …Hollyhock, Althea, with flat, brown seeds, about 50 in a seedpod…
Slide 12. …Hyacinth vine, Dolichos, with large black seeds, three to four seeds in a seedpod…
Slide 13. … and Feathered amaranth, Celosia, with small, round black seeds. When you collect seeds,
make certain they are completely mature. Leave the fruit on the plant until they are dry, crisp,
papery, or stiff. Usually the ripe seeds are exposed. The best time to gather seeds is in the
afternoon on a sunny, dry day, as wet seeds often mold in storage. Clean the seeds by pouring
them from one jar to another in front of a low-speed fan; this removes any dry plant parts. After
cleaning, spread the seeds on newspapers to dry for one to two weeks. They can then be stored
in small, dry bags or placed in jar or other airtight container. Store the jars in a cool, dry
basement, the vegetable crisper of your refrigerator, or an interior closet.
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Slide 14. Ferns are propagated from spores, which are extremely small, almost powder-like. Ripe spores
are brown and located on the underside of the fronds, where the fern fruiting structures, called
sori are. The Leather leaf fern (pictured in photos one and two), has round fruiting structures,
while Bird nest fern (in photo three) has fruiting structures, arranged in rows on either side of
the midrib. To collect the spores, hold a white sheet of paper underneath the frond and tap
gently. Scatter the spores on the surface of a sterilized medium, usually one high in organic
matter such as peat moss. Cover the container with a pane of glass or plastic to retain moisture.
Place in a window receiving filtered light (rapid heating can occur under glass or plastic in
direct light) or under artificial light. It takes several weeks, sometimes months, for the young
plants to germinate and reach sufficient transplanting size.
Slide 15. The basic tools necessary for propagation are inexpensive and can be found in most garden
stores. Start with various sizes of clay or plastic pots with drainage holes. Plants planted in clay
pots require more frequent watering because water evaporates through the pot. Plastic pots are
less expensive compared to clay pots. You will also need potting mix with good aeration and
water holding capacity. Commercial grade potting mixes available from garden supply stores
are suitable or you can also mix your own by using equal parts perlite, vermiculite, and milled
sphagnum moss, or equal parts of sand and peat moss. Small river stones are needed to prevent
the potting mix from coming out of the pot’s bottom. You will need rooting hormones, which
are especially important if you’re propagating woody plants. Sharp clippers are necessary for
taking cuttings or making cuts; straight edge ones are preferable for making clean cuts and for
herbaceous plants. Finally, you will need plastic bags or plastic wrap, alcohol for disinfecting
the clippers, misting nozzle, and labels.
Slide 16. Make sure you have a hose breaker (on the left), to water newly rooted plants and a misting
head (on the right), to mist freshly planted seeds and cuttings. The mist provides small sized
water droplets, which increase humidity without supplying too much water or washing the
seeds out of the potting mix.
Slide 17. Start by placing a single layer of small river stones at the bottom of the pot. The common
practice of placing stones or broken clay pot pieces on the bottom of the pot does not help
improve drainage. However, it does help to keep the potting mix from coming out of the
bottom holes. Fill with the potting mix and then water thoroughly. Make sure that the potting
mix is sufficiently moist throughout. A potting mix that had dried out completely is very
difficult to moisten.
Slide 18. Place small seeds on a folded sheet of paper and then tapped gently to dispense them.
Crowding of seedlings could result in poor air circulation and cause damping-off, a disease,
which attacks seedlings at the soil line. Small seeds are usually left uncovered. In this case, a
very thin layer of vermiculite helps keep high humidity around the seeds. When buying
packaged seeds, make certain you read the label to determine if the seeds should be covered.
Slide 19. Plant large seeds, such as these of Hyacinth vine at a depth about twice their size. Label the
pots and apply mist. Cover with a plastic bag to prevent the medium from drying out. A clear
plastic shower cap works very well because it has a round shape and an elastic band, which can
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accommodate different pot sizes. Remove the plastic film once the seedlings emerge. Check
germination medium daily to make sure it stays moist. Temperature should be 60-650. Bottom
heat (70 - 750) usually speeds germination, but it is not required. Place the pot under filtered
light. Once the seedlings emerge, increase the light. After the first true leaves appear, transplant
the seedlings by dislodging them gently from the germination medium. Handle seedlings by
their root balls or by their leaves, never by their stems. Transplant to a new container at about
the same depth, firm the soil around the roots, and water thoroughly.
Slide 20. Let’s look at the science behind vegetative propagation. In vegetative propagation a plant part
is placed under conditions favorable for rooting. Size of the plant part varies from large as the
mature plant (e.g. division), to as small as a piece of the leaf. The vegetative plant part must
develop its own roots to allow for water and mineral absorption.
Slide 21. This is achieved by formation of adventitious roots. They arise on aerial plant parts (stems,
leaves) or on underground stems, sometimes in great numbers.
Slide 22. There are two types of adventitious roots: preformed, as in the ivy stem on the left or woundinduced, as is in the woody cutting on the right. Adventitious root formation is a prerequisite to
successful cutting propagation.
Slide 23. Although factors, which trigger adventitious root formation are still unknown, we know plant
hormones play a role. Hormones occur naturally in plants. They regulate plant’s physiological
processes. Some hormones are involved in the formation of adventitious roots and are present
in buds. Scientists have isolated and identified these substances. Synthetic rooting hormones
are root-promoting chemicals that stimulate adventitious root formation.
Slide 24. Application of rooting hormones is especially important in propagating woody plants by
cuttings. Rooting hormones are available as powder or liquid formulations. Some of the
popular brands are Rootone, Rhizopon, Dip’n Grow, and Hormex. Rooting hormones are
available from most garden stores.
Slide 25. The last element of vegetative propagation involves adventitious buds. Some plants are
propagated from leaf cuttings. This is possible because they have adventitious buds that exist in
the leaf tissues. Under favorable conditions adventitious buds within the tissues of the leaf
“awaken” and prompt development of an entire miniature plant.
Slide 26. Plants may be vegetatively propagated from: plantlets, divisions, layering, root cuttings, or
shoot cuttings. Shoot cuttings may be tip, stem, or leaf cuttings. Vegetative propagation
generates a complete replica of the parent plant. Sometimes, however, when the parent plant
contains tissues and cells with differing genetic makeup, the new plant generated from that
tissue may look different than the parent plant. An example is a chimeral African violet
propagated from leaf cuttings may generate two or more distinct flower color forms from a
single leaf. Chimeral plant contains cells with differing genetic makeup.
Slide 27. One of the simplest vegetative propagation techniques involves removing plantlets from the
mother plant. Plantlets are miniature, but complete plants, which grow by the side of, or on the
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top of the mother plant. Other names for them are “runners” or “suckers.” Plants propagated by
plantlets include…
Slide 28. … Spider plant, Chlorophytum, produces large quantities of plantlets at the tips of long
flowering stems. Any size plantlet will grow roots and quickly develop into a mature-size plant.
Some plantlets form roots while still attached to the mother plant.
Slide 29. Place plantlets on a well moistened potting mix, press its bottom into the mix and firm the soil
around it.
Slide 30. Another plant, easily propagated by plantlets, is the Strawberry geranium or Strawberry
begonia, Saxifraga. Just as the Spider plant, small or large plantlets could be removed using the
same technique.
Slide 31. Some species of Kalanchoe develop small plantlets at their leaf edges. These plantlets fall to
the ground where they form roots and grow into mature plants. The Kalanchoe in this photo is
called Chandelier plant.
Slide 32. You can remove the tiny plantlets and plant them in separate pots. Within several months, a
one-eight of inch plantlet will grow into a 2-inches tall young plant as shown in this picture.
Slide 33. Other Kalanchoes have plantlets that develop roots while they are still attached to the mother
leaf. When these plantlets come in contact with the potting soil, roots quickly grow and anchor
the young plant. Cover the pot with plastic for a few days to keep the potting medium from
drying out and remove the plastic once plantlets show growth (usually in several days.)
Slide 34. Medicine plant, Aloe, forms offsets at the base of the stem. They can be removed and planted
in pre-moistened medium in separate pots. These offsets may or may not have developed their
own roots. Either type will propagate with ease.
Slide 35. Screw pine, Pandanus, is an excellent houseplant when it is young and has an undivided
crown, but the time usually comes when they become too large for their location and are
cluttered with surplus shoots. Remove some of the shoots by cutting them as near to the parent
stem as possible and planting them in a moist medium in a separate pot.
Slide 36. Division is one of the surest and easiest methods of plant propagation. It is done almost
exclusively to herbaceous plants. It is important to divide plants when they are dormant in
spring or fall. A good general rule to follow is to divide early-blooming species in the fall, and
late-blooming species in the spring. Bearded Iris may be divided from July to September.
Oriental poppy and Madonna lily should be separated when the foliage becomes yellow. An
exception is Primrose can be divided immediately after the flowers fade in the spring before
growth starts, or early in the fall. Greenhouse and houseplants can be divided in the spring,
when their new growth is about to begin.
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Slide 37. A root-bound plant purchased from a nursery, may be divided into two plants, or many plants.
In this case, a Society garlic plant is taken out of the pot and with a sharp knife, the crown is
divided in two parts, which are planted separately.
Slide 38. As the number of cuts and individual divisions increase, there is a higher risk of wilting or
disease attack through the wounds. When planting in the garden, place divisions in a specially
prepared bed where the soil has been amended by organic matter. Also, the new divisions
should be shaded for the first few weeks.
Slide 39. Bugle weed, Ajuga, is an excellent groundcover for shade, and it spreads easily through
underground stems. The individual plantlets can be easily lifted with a spade and transplanted
elsewhere in the garden.
Slide 40. Layering is a method of vegetative propagation in which adventitious root formation is
prompted while the plant part is still attached to the parent plant. Two methods of layering
commonly used to propagate ornamental plants are air-layering and ground-layering. We will
discuss ground layering later in the woody plant propagation.
Slide 41. Air-layering is often used on the main stems of older house plants, such as Fiddle fig, Rubber
plant, Dumb cane, and Chinese evergreen, which have lost their lower leaves and become
leggy. Red edged Dracaena is shown here. First select a branch, which will be the future
separate plant. Next, wound the stem where you want the roots to appear. The stem may be
wounded on two sides or by making a cut three-quarters of the way through the stem at 45
degree angle. With the second method, insert a toothpick to keep the cut from closing and
sealing itself.
Slide 42. Next, apply rooting hormone to the cut using a paintbrush. Then wrap the cut in sphagnum
moss that has been soaked in water and wrung out. Then wrap a piece of clear plastic around
the moss ball and tie it at the top and bottom. When roots emerge from the ball, cut the stem
just below the roots and transfer the new plant to another pot.
Slide 43. Commercial catalogs often lump bulbs, corms, tubers, rhizomes, and rootstocks together under
the category “bulbs”. Botanically speaking, each of these structures is different.
Slide 44. Bulbs are made up of closely packed, fleshy scale leaves attached to a small basal plate of
solid tissue. Examples are Amaryllis, Onion, Tulip, Narcissus and Lily.
Corms are similar in appearance to bulbs but they are solid throughout with small buds
ultimately forming on the top. Examples are Gladiolus and Crocus.
Tuber is a swollen stem, as in Potato.
Tuberous roots are swollen roots, as in Dahlia and Begonia.
A rhizome is a thickened shoot, which grows underground or along the soil surface, producing
roots from its undersides and leaves or shoots above the ground. Example is Solomon’s seal.
Slide 45. The thickened, tuberous rhizomes of Calla lily, Zantedeshia, resemble bulbs.
Slide 46. The first step in propagating Gladiolus is to dig up the old corms after the leaves have died.
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Slide 47. On this freshly dug Gladiolus corms one can see a new daughter corm, an old mother corm,
and one much smaller corm, called a cormel. Growth of leaves and flowers occurs at the
expense of the corm’s food reserves. After flower initiation, one or two new corms develop and
the mother corm eventually withers. The small cormels can be removed from the daughter
corm and planted separately. They will flower in a few years.
Slide 48. Tall Bearded Irises are rhizomatous plants. They can be increased by dividing the rhizomes
between July and October. Dig up the rhizomes by inserting a spade about 10 inches away from
the leaves and lifting the whole plant. The rhizome appears underneath the leaves and looks
like a brown stem with roots.
Slide 49. Separate the individual plants by cutting through the rhizome. Cut the leaves to within a third
of their length. They are now ready for planting to their new location.
Slide 50. Cast iron plant, Aspidistra, is propagated like Iris. The rhizome grows along the soil surface
and is visible without digging. Cut through the rhizome and lift the roots from below.
Slide 51. The rhizome, with four shoots, is now ready for planting in a new location.
Slide 52. To better understand the different types of shoot cuttings, let’s look at the parts of the plant
shoot.
Slide 53. A typical herbaceous stem has an apical bud from which the plant grows in height. The nodes
are places on the stem where leaves are attached. Axillary buds are found at each node.
Slide 54. Shoot cuttings may be made from: tip cuttings, which consist of the apical bud and the first
one or two nodes on the stem, or they may be made from a stem section containing a single
node or several nodes.
Slide 55. Here is an example of one tip (left) and one node cutting (right) from Cape primrose,
Streptocarpella. It is very important to have at least one bud on the cutting. Buds are a source
of natural hormones, which play a role in adventitious root formation.
Slide 56. Shown at the top is a tip cutting from Umbrella plant, Schefflera. The bottom leaves are
removed to decrease the leaf area and help to conserve water while the cutting is forming roots.
Insert the cutting about two inches deep into the soil mix.
Slide 57. Similarly Begonia is propagated from tip cuttings. It is a good practice, however, to remove
any flowers, if present, which helps the cutting direct its energy to roots instead of flowers.
Also, flowers rot easily under high humidity and would become a source for a disease.
Slide 58. Coleus roots very easy from tip or node cuttings. Coleus shoots also can be placed in water and
will form roots in about a week.
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Slide 59. When making a tip cutting, remove the bottom leaves and very young growth since it will be
placed under the soil line.
Slide 60. White velvet, Tradescantia, is related to Wandering jew. These plants root incredibly fast.
However, avoid creating an environment that is too humid because leaves may rot. It is best to
water from below and allow capillary action to moisten the soil.
Slide 61. Houseplants with vining habit, such as the Wax plant Hoya, are propagated from cutting the
stem into one-node cuttings.
Slide 62. The red lines in the left photo indicate where to cut to produce a single one-node cutting. The
right photo shows where to cut for a tip cutting. In this case, the middle portion of the stem is
discarded.
Slide 63. The Velour philodendron, with its dark-brown velvety leaves, is a very attractive houseplant.
However, its rigorous growth may make it crawl into every corner of your home. When this
occurs, it’s time to propagate them and reduce their size.
Slide 64. Velour philodendron can be propagated it by tip or one-node cuttings as shown. A perfect oneleaf, one-node cutting is shown on the right. The axillary bud is hidden within the leaf petiole,
which tightly clasps the stem. Devil’s ivy, can also be propagated using this method.
Slide 65. Arrowhead vine, Syngonium, is propagated from tip or one-node cuttings as shown. Note the
long adventitious root formed at the node. When propagating vines, insert the cutting deep
enough, so that the node comes in contact with the potting mix. Adventitious roots like those in
the bottom photo will become functional roots, developing root hairs for water and mineral
absorption.
Slide 66. Sweet potato vine, Ipomea, has become very popular in recent years. This vigorous vine is
used as a groundcover or in containers. Several cultivars with colorful foliage are available
commercially. Pictured here is ‘Blackie’. Take tip or stem cuttings from these vines in late fall
and root them in water or media and overwinter them indoors for planting next spring.
Slide 67. Many shoot cuttings can be propagated in water, provided that there is good light. They take
from one day to one month to form roots. Be sure to top off the water level daily, as it can
evaporate quickly. After roots have formed, the cuttings can be planted directly in potting soil.
One disadvantage of rooting cuttings in water is that the roots that are formed are much finer
than those formed in solid rooting medium. Water-rooted cuttings tend to suffer from shock
when transplanted to soil. Keeping them misted for the first few days after transplanting should
increase their chances for survival.
Slide 68. You can also make the so-called ‘Forsyth’ cutting pot to start several different cuttings at once.
It consists of a bulb pan in which small, unglazed clay pot is inserted. The drainage hole of this
pot is plugged either with floral clay or chewing gum. The bulb pan is filled with vermiculite.
The small pot is kept filled with water. After the initial watering the seepage from the central
pot usually is sufficient to keep the rooting medium moist.
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Part II.
Slide 1. Many plants can be propagated from leaf cuttings.
Slide 2. Snake plant, Sanseveria, is propagated from leaf cuttings. Cut the thick leathery leaves into 3 to
4 inch-long sections and insert them three-quarters of their length into the rooting medium. To
avoid sticking them upside-down in the medium, cut the basal end on a slant, as shown with
two of the cuttings (yellow arrows). The variegated form of Sanseveria, like the one shown is
an example of what scientists call a chimera, a plant that has tissues with different genetic
makeup. In this case, the yellow leaf parts differ from the green leaf part. This plant will not
reproduce true-to-type from leaf cuttings because the new plant will be initiated from
adventitious buds that originate either from the green or the yellow parts but not from both. To
retain the variegated form, you must propagate by division of the original plant.
Slide 3. Mother of pearl plant, Graptopetalum, is another example of a plant easily propagated by leaf
cuttings. Simply remove the leaves by twisting them from the mother plant and inserting the
bottom part in the potting medium.
Slide 4. Once new plants develop from the end of the leaf cutting, remove and plant them in a separate
pot.
Slide 5. Many succulent plants can be propagated from leaf cuttings, including Burrow’s tail, Sedum,
and Jade plant, Crassula…
Slide 6. … as well as all Kalanchoe species.
Slide 7. Rex Begonias can be propagated from leaf cuttings. To do this, make several slits through the
major veins of mature leaves. Lay the leaf flat, with the top side up, on a moist potting medium.
When using several large leaves, a flat tray works well.
Slide 8. Place small stones on the leaves to hold them flat. Then mist, and cover the rooting container
with plastic. A single leaf may produce many small plants, which should be removed and
planted separately.
Slide 9. Holiday cacti consist of three species; Thanksgiving, Easter, and Christmas cacti, all very
similar in appearance. They consist of modified stems, called phylloclades, which are flat, leaflike structures that photosynthesize. They are easily propagated from single or double stem
sections. Simply remove the sections by twisting them 180 degrees, thereby separating them
from the mother plant. Insert the bottom one half-inch into the rooting medium. Avoid using
segments near the soil because they are more likely to be contaminated with soil pathogens
than segments from higher up on the plant.
Slide 10. String of pearls, Senecio, is a curious plant whose leaves resemble little green spheres attached
to slender stems. It bears white, funnel-shaped, cinnamon-scented flowers. Propagate this plant
by removing a two-inch piece of the stem with leaves attached and planting it in moist soil.
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Slide 11. African violets are popular houseplants. They come in a variety of flower colors and leaf sizes.
There are standard, semi-miniature, and miniature forms. African violets can be propagated in
several ways, and they are an excellent plant for learning about plant propagation methods.
Slide 12. As plants mature, they can become quite large and top-heavy. This plant is not only big, but it
also shows a split crown, with two smaller crowns on each side.
Slide 13. Take the plant out of the pot and shake the excess soil from the roots. You can then see how to
divide the crowns. Use a sharp knife to cut through the root mass. In this case, two individual
plants were produced. Sometimes, gently pulling the crowns away from each other is sufficient
to split them apart.
Slide 14. On a mature plant, new crowns appear at the base of the mother plant. These offsets can be
removed and planted.
Slide 15. White plastic potting labels are used here to show the offset. Use a sharp knife to cut it away
from the main crown and plant.
Slide 16. African violets also can be propagated from the flower stalks, which bear small leaves with
buds. Cut the flower stalk away, remove the flowers, and plant the stalk.
Slide 17. Another popular method to propagate African violets is by leaf cuttings. Use mature leaves
from the outside of the crown. Stick leaves at an angle in a moist rooting medium. The leaves
also will root in water.
Slide 18. Ideally, African violets should be watered from below, to keep the foliage from trapping
moisture and rotting.
Slide 19. An inexpensive way to create self-watering container, is to insert a cotton wick into the
growing medium.
Slide 20. Then purchase two small plastic saucers (about $ 0.14 each). Cut a round hole in the bottom of
one of them to allow for the pot, and a triangular hole at the rim. Place one saucer on the top of
the other intact saucer. Then use clear tape to secure both saucers to one another, making sure
they are lined up at the rims.
Slide 21. You now have a self-watering container, which can be filled through the hole at the side. For
larger containers, use two saucers on the top and two at the bottom to provide greater strength.
An even less expensive solution is to use the bottom part of a plastic soda or water bottle for a
self-watering container.
Slide 22. In recent years, orchids have become affordable for most households. Many of us have an
orchid in our plant collections.
Slide 23. But what do you we do once the beautiful Cattleya looks like it is ready to jump out of the pot?
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Slide 24. Let’s look at the structure of a Cattleya orchid. It has roots, stems, leaves and flowers. But
these are adapted to the orchid way of life, and therefore differ somewhat from most plants.
Most of the orchids in cultivation are epiphytes (pronounced “EP-e-fights”) or air plants. They
grow in trees and rocks instead of soil. This puts the roots out into the air. Leaves and flowers
arise from a structure called pseudobulb. Cattleyas belong to a group of orchids that have a
growth habit called sympodial (“sim-PO-dee-al”.) This growth habit is entirely different from
that of most garden plants. For instance, a shrub has a single main stem or trunk. As it grows, it
branches upward and outward from this main stem, growing from terminal buds at the ends of
the branches or twigs. A sympodial orchid does just the opposite. Instead of branching out from
a stem, it puts up another growth just like the one before. The new growth has its beginning at
the base of the newest existing bulb. It grows sideways. Sympodial orchids can be propagated
by dividing the older bulbs (called “back bulbs”) located at the back of the plant.
Slide 25. What you need for potting orchid divisions is a soft string for tying the leaves to a stake,
special orchid fiber for packing around the roots, bark chips, river gravel to keep the fiber or
bark chips from coming out of the pot’s holes, a sharp knife, and a clean porous clay pot. All of
these supplies are readily available in most garden centers.
Slide 26. Traditionally, most orchids have been grown in unglazed, porous clay pots. Over time, the clay
containers may become unsightly with algae and salt stains. In recent years, a new orchid pot
design has brought functionality and attractiveness to the traditional orchid pot. They have
round holes all over to allow better air circulation. Both glazed and unglazed pots are available.
Slide 27. Start with placing one layer of river gravel on the bottom of the pot.
Slide 28. Next place the back bulb near the edge of the pot with the new growth facing forward. This
placement is necessary because the orchid will form new bulbs in front of the old ones.
Slide 29. This green bud will develop into new growth. Every back bulb has to have at least one green
bud.
Slide 30. This is an overgrown Cymbidium, ready to be propagated and repotted.
Slide 31. Leaves have been moved aside so we can examine the plant. The back bulbs in this plant
appear dead and need to be removed. New growth is healthy and is found at each side of the
back bulbs.
Slide 32. Use a sharp knife to cut through the middle of the plant and separate the back bulbs from the
new growth.
Slide 33. These are the resulting two divisions. When separating them, we slowly pry the roots from the
two divisions away.
Slide 34. Cut off any dead roots. A cut is made through the first division to obtain two smaller divisions,
with three bulbs each. This is a sufficient number of bulbs to support new growth.
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Slide 35. Then wrap moist fiber around the roots and place the division near the edge of the pot, with the
new growth facing forward.
Slide 36. Pack the fiber very firmly around the roots to keep the plant upright. Place bark chips on the
top of the fiber. Stake with a twine secured around the newly potted orchid. Place the plant in a
shaded spot for a few weeks and make sure that the fiber stays moist. However, before
watering, make sure that the fiber near the bottom of the pot is dry; often the top appears dry
when the inside is still moist.
Slide 37. Many woody ornamental plants are propagated from cuttings. However, two things are crucial
to success: taking the cuttings at the right time and providing a suitable environment for root
initiation and development.
Slide 38. Loropetalum, for instance, is propagated from the flexible young growth, or semi-hardwood.
The best time to take softwood cuttings is from June to September. In the spring, the growth is
often too tender and succulent and will not propagate well.
Slide 39. If you’re working with larger branches, use only the semi-hardwood cuttings. Make the cutting
about 6 inches long and remove the leaves from the lower half to one-third of the stem.
Slide 40. Another woody plant commonly propagated by semi-hardwood cuttings is Azalea. Take
cuttings from the upper part of the plant, making a slanting smooth cut with sharp clippers at
the basal end. This slanting cut is made to provide a larger area from which the adventitious
roots will form.
Slide 41. The cutting should be about 4 inches long.
Slide 42. Another plant easily propagated by semi-hardwood cuttings is Camellia.
Slide 43. Again, make a slanting smooth cut with a knife or sharp clippers at the basal end. Remove any
flower buds. Wound the lower half-inch of stem on the opposite side of the last node.
Slide 44. Holly is also propagated from semi-hardwood cuttings.
Slide 45. Juniper cuttings are made using a slightly different technique. Select a side branch that is 5 to 6
inches long. While holding the main stem firmly with one hand, tear away the side branch and
make sure that a small piece of the main stem is still attached to it. This is called a ‘heel’
cutting.
Slide 46. Close up of two Juniper cuttings.
Slide 47. Woody plant cuttings will root faster and form better roots when treated with rooting
hormones, such as Rootone. Dip the base of the cutting in a small saucer containing the white,
powdery compound.
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Slide 48. Place the cutting one to two inches deep in the medium, with one to three nodes below the
surface. The lower leaves of the cutting should not touch the medium. Firm the medium around
the base of the cuttings to hold them upright.
Slide 49. Water thoroughly to settle the medium. Place a plastic bag around the pot making sure that the
bag is secured around the bottom of the pot. Keep the plastic from touching the leaves by
placing one or two 12-inch stakes in the pot. Uneven moisture distribution during rooting is the
most common cause for rooting failure. Make sure the rooting medium stays moist, but not too
wet.
Slide 50. The picture on the left shows callus formation on the cutting. Although callus usually precedes
root formation, such extensive callus is not a good sign. A possible cause is insufficient rooting
hormone application when the cutting was stuck. The picture on the right shows roots
protruding from the mass of callus. This cutting has successfully rooted.
Slide 51. Some woody plants are propagated by ground-layering.
Slide 52. Ground-layering is done outside, in the landscape. It works best with plants that have arching
branches that can be brought down in contact with the ground. This Oak leaf hydrangea had a
branch that was perfectly positioned for ground-layering.
Slide 53. First, the soil is improved for ground layering by mixing sand and peat moss in it.
Slide 54. Then, a slit is cut in the stem of the selected branch at the point where roots are wanted. The
‘tongue’ made by cutting into the stem is held open by a toothpick, and the wound is dusted
with a rooting hormone using a soft brush.
Slide 55. The shoot is placed in a 2-inches deep trench and covered with soil.
Slide 56. Finally, the layer is watered and a rock is put over it to keep the layer in place and to help
conserve moisture in the soil.
Slide 57. Before we finish our presentation let’s look at some common sense tips that can save you some
headaches and increase your chances of success when propagating plants.
Slide 58. Do not use cuttings from plants that are infected with pests. This picture shows mealybugs on a
geranium cutting. Mealybugs are among the most feared pests, especially in the home, because
they are difficult to spot and control. Before you take a cutting, inspect the plant very carefully.
Slide 59. This picture shows aphids on China doll leaf. Although much easier to kill than mealybugs,
aphids can still be a nuisance. Be especially careful when you share cuttings with friends.
Discard any plant material that appears unhealthy or shows pest infestation.
Slide 60. Likewise, do not use cuttings from diseased plants. Both the ivy on the left, and the Cape
primrose on the right suffer from a disease. Propagating these plants will likely spread the
disease to the new cuttings or divisions.
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Slide 61. There is always a lot more to learn about a particular subject, and plant propagation is no
different. Many books are written about plant propagation, many of which are on an amateur
level and do not delve deeply into the subject. For those of you who are interested in the
science behind propagating plants, this book is an excellent source. It is a standard textbook for
horticulture students and contains detailed information on various methods and techniques that
are used in commercial plant propagation.
Slide 62. Credits.
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