Propagation of Ornamental Plants
Plants usually reproduce in two ways:
- By seeds and
- By vegetative parts of plant.
The letter method is very popular in the multiplication of fruit and ornamental plants.
Sexual propagation or propagation by seeds
This is the easiest method of propagation of plants. In this method the seeds
are sown, covered with a layer of soil or leaf mould and watered. After germination the
seedlings are allowed to grow up to 4-leaf stage and then they are transplanted in the
beds or pots. In some cases the seeds are directly sown in the ground. These seeds
originate by the union of male and female gamete. During pollination pollens of male
reproductive organ female reproductive organ. When the ovules are fertilized by the
pollens of the same flower the process is known as self-pollination. Cross-pollination
occurs when the pollens come from a different source and usually the pollinating agents
are wind or insects. Self-pollination occurs when the pollens come from a different source
and usually the pollinating agents are wind or insects. Self-pollinated seeds are likely
true to type or variety, but the cross-pollinated ones may not resemble the parents for
all the character. After pollination, male gametes fertilize ovules resulting in the
production of seed.
A sexual or vegetative propagation
The following are the reasons for propagating plants vegetatively:
- Many plants do not produce seeds under
local condition or have lost the ability of production of viable seed. It is found in
several cases that plants which readily root from cuttings do not produce seeds e.g., Acalypha,
- Plants, which are cross-pollinated and
have different varieties in cultivation, produce seeds of heterogeneous mixture. In such
plants particular type can be maintained only by vegetative method or by careful
crossbreeding with the same variety.
- Double dahlias when grown from seeds
show a wide range of colour and also a mixture single, and semi-double. Apple pear, peach,
mango etc., do not grow true to type from seds.
- Vegetative method of propagation
results in earlier flowering and fruiting than those raised from seeds. Vegetative part of
a fruiting plant is mature to bear, while a seedling take few years before the shoots
ripen to produce flowers and fruits. Seedlings of Amherstia nobilis or Brownea
ariza require 7-8 years to flower but a layer starts flowering in the second year.
- Plants are also vegetatively propagated
to increase their resistance or to develop immunity to particular disease or pest.
- A well-rooted vegetative part of a
plant can adapt more readily to new environment and has greater possibility to flower and
fruit than a seedling.
Many parts of plant are capable of giving rise to new plants under natural condition.
Bulbs are underground-modified stem in which the central axis is much shortened and fleshy leaf
scales are closely pressed. Amaryllis, Crinum, Hymenocallis, Hemerocallis and Haemanthus,
are usually multiplied by bulbs which arise from the main bulb. Cooperanthes, Zephyranthes
and tube rose are also manly grown from bulbs.
Gladiolus produces new
corms and cormels on old ones, which are used for multiplication.
Rhizomes, tubers and
fleshy roots. Rhizomes are defined as more or less cylindrical branches growing laterally
or upward through the soil. Many ornamental plants such as Calathea, Anthurium,
Alocasia, Alpinia, Hedychium, Heliconia, Gloriosa, Canna produce rhizomes or
rhizomatours stem with buds on it which can be cut into pieces and each one will produce a
new plant. Root tubers of dahlia are storage organs and shoots arise from stem attached to
When a slender stem
grows out of a crown and trails along the ground it is called a runner or stolon.
Chlorophytum, Episcia send out stolons and produce young plants from the nodes. It is then
detached and grown separately.
Many ornamental plants
are propagated by this method. Sanseviera and Agave americana send out
branches terminating in rosette of leaves which ultimately grow as new plants. These can
be separated from the mother plants. Chrysanthemums also produce offsets, which are
detached for multiplication of plants. Gerbera also sends out suckers on offsets.
There are some plants,
which produce suckers from roots and are detached from the mother plants for
multiplication. Millingtonia hortensis, Clerodendron splendens, Quisqualis indica are
Propagation of ornamental plants
Most of the species of
trees; grown in tropical conditions are raised from seeds. The seedlings with taproot grow
tall and large and give necessary support against storm. Some species, however, often fail
or produce seeds irregularly.
Species of Cassia
and Poinciana regia, Thespesia populnea, Peltophorum ferrugineum, couroupita guinensis,
Acacia auriculi formis, Pithecolobium saman, Saraca indica, Spathodia campanulata,
Lagerstroemia flos-regineae and many other flowering trees produce seeds freely which
germinate in seed compost consisting of garden soil and leafmould, one part each in bed or
in seed pans. Seeds or mahogany have spongy seed coat and rot in excess moisture. Seeds of
Polyalthia do not germinated if they become too dry. Seedlings of Eucalyptus
and Jacaranda grow well in less humidity and temperature and should be sown in the
Plumerias root easily
from stem cuttings. Cuttings are made in spring as excessive moisture in soil causes
rotting. These are planted in sandy soil and light watering is done after callus
formation. Plumerias produce large fruits containing many seeds but the seedlings do not
flower before four years. Cutting from mature terminal shoot start flowering within few
months. Gliricidia are also propagated from cuttings. In the case of Spathodia
campanulata in addition to seed propagation, root suckers are also used.
Air layer and ground
layer. Gustavia augusta, Brownea ariza and B. grandiceps though produce few fruits
every year but the seedlings are very slow growing and are also propagated by air or
ground layering. Ficus elastica and Ficus krishnae and F.benjamina are
easily propagated from air layer.
Few species of shrubs
which produce seeds and the seedlings flower in one or two years without changing the
character, are raised from seeds e.g., Galphimia gracilis, Cassia glauca, Cassia
didymobotrya, Solanum macranthum, Tecoma stans, Sophora tomentosa, Brya ebenus, Callindra
speciosa Bauhinia acuminata, B. tomentosa and Caesalpinia pulcherrima speciosa, Ochna
wightiana, O.squarrosa, Carissa carundas, Jacquinia ruscifolia, Bauhinia galpinii,
Portlandia grandiflora and Calliandra speciosa do not root easily from cutting
and layering and so seed multiplication is commonly practised.
All species and
varieties of Acalypha, Angelonia, Aralia, Asystasia, Buddleia, Cestrum, Daedalacanthus,
Eranthemum, Graprophyllum, Justicia, Lagerstroemia indica, Malvaviscus, Pentas,
Poinsettia, Russelia, Jasminum sambc, Brugmansia, Stachytarpheta and Thunbergia are very
easily propagated from cuttings. In Aralia, Eranthemum, Pentas, Aphelandra and
Daedalacanthus, tip cuttings produce quicker and better roots.
Green house plants
thrive in shade and grow well in high humidity especially during the hot months. These are
mostly grown for beautiful foliage though flowering plants like Achimines and Pelargonium
need suitable protection during dry and hot season.
Seeds Plants can be raised
from seeds of Coleus but to maintain a particular variety vegetative propagation
has to be done.
All the different
species and varieties of Aglaonema, Philodendron, Anthurium, Scindapsus, Monstera and
Dieffenbachia, have succulent stem which are cut into small pieces keeping one node in
each and planted in ground or pot. The cuttings are planted horizontally about 1-2cm below
the soil with the bud pointing upward. Several species of Dracaena e.g., Dracaena
ugandense, D.victoria, D. deremensis "Bausii" D. reflexa
"Variegata" are grown from top cuttings. The erect stem can also be cut into
pieces with few nodes in each cutting and planted in soil. Top cuttings produce
well-shaped plants after root formation, while shoots from lower cuttings have slower
growth. Episcia, Syngonium, Gynura, Fittonia, Pellionia, Coleus, Zebrina Pendula,
Setcrasea Purpurea, Perperomia, Pillea and Strobilanthes dyerianus are propagated from
stem cuttings. It is safe to plant these soft cuttings in sand only. After root formation
it can be transferred in pot or ground. Foliage begonias and African violets can be
propagated from leaf cuttings but division is a safe method under our climatic conditions.
Species of ferns, e.g., Nephrolepis, Pteris, Ptyrogramma, Polypodium and Davallia
are divided with crown and rhizome. All palms produce seeds in suitable climate after
attaining maturity. Pritchardia, Caryota, Livistonia and Oreodoxa often for
seeds in Calcutta.