Plant Propagation
May 12, 2004
By Suzzanna Walsh, Master Gardener
Ah, Spring. The sun is out. The weather is warming. A gardeners fancy
turns toward love…of their garden! Seed
catalogs clog the mailbox. Garden
tours and spring nursery sales abound. We
walk our gardens plucking weeds, cursing snails, and fantasizing new flower
beds.
Spring could also be the right time for you to start propagating new plants. Plant propagation is the process of increasing the numbers of
a given species. For many of us the idea of plant propagation is just a little unnerving. We have all had people in our life, like my
Grandfather, who could make anything grow - from seeds or
cuttings to a specimen of vigor and marvel.
My Grandpa had the greenest thumb and he left behind a very
intimidating legacy. As Henry D Thoreau
said “Spring - an experience in immortality”.
So, with plant propagation, let’s experience a little immortality. There are several ways to propagate a plant. You can start plants from seeds, from
cuttings, layering, through separation and division, and by grafting. Grafting is very specialized and won’t be
discussed in this article.
Seeding
Starting your own plants with seeds is not only frugal, but gives you a much bigger
variety of plants to choose from. There
are four environmental factors necessary for seed germination: water; oxygen;
light; and temperature. Your seed packet
should give you specific information regarding these four elements. Simply put:
your seeds need to be kept moist, in a planting medium that provides adequate
oxygenation, given good light and a warm temperature. Choose a planting medium that is one third
sterilized sand, one third vermiculite or perlite, and one third peat moss. You can also purchase compressed peat pellets
which can be directly planted when your seedling is ready. Place your planting medium in your chosen
container. Your container can be
anything that has adequate drainage and doesn’t have to be specific to the job. Remember starting plants in
milk cartons as small children? Have fun
and use whatever you have. I keep empty
pony-packs as well as cell trays for this purpose.
Now, plant that seed. I love this part. Have your containers ready with their planting medium. Make your markers
with type of plant and date of planting.
Read your seed packet for planting depth, and length of germination. Move your container to a well lit and warm
area, keep moist via a fine mist, and …wait.
I planted some seeds on the 5th
of this month and seedlings appeared by the 10th.
Cuttings
Propagation through cuttings is the process of using a piece of an existing plant and inducing it to
regenerate itself, thus forming a new plant.
Stems, leaves and roots can all be used for cuttings. This is a good method for woody and
herbaceous plants. Always seek your
cuttings from healthy and vigorous plants.
Use a clean and sharp knife or razor blade to make your cuts. Ensure cleanliness by dipping your cutting
tool in rubbing alcohol or a solution of one part bleach to nine parts
water.
Stem cuttings are probably the easiest and
most common method. To propagate from
spring growth of deciduous or evergreen plants, use the softwood stem tip cutting method.
Detach a two to six inch piece of stem, including the terminal bud. Make your cut just
below a node. Remove flowers and flower
buds so that all the plant's energy will go to root formation. Also, remove all lower leaves that might
touch the rooting medium.
Dip your cutting into a rooting hormone and then place it into rooting medium such as a mixture of sand, vermiculite,
soil and water, or a mixture of peat, vermiculite and perlite. Keep your cuttings moist and you should have
roots in two to five weeks.
Cane-like stem cutting are used to propagate plants such as Dracaena spp.
and Dieffenbachia spp...
Cut your cane-like stem into sections containing one or two nodes
each. Apply a fungicide or activated
charcoal to the ends and set them aside to dry for several hours.
Lay your cutting horizontally in the rooting medium with an eye facing upward. Pot your cutting when roots and new shoots
appear.
Take cuttings from semi-hardwood plants such as Camellia spp.,
holly, and Euonymus spp. (semi-hardwood) between mid-July and
early September. Take a cutting three to
six inches long and remove the leaves from
the bottom half.
Use a rooting hormone on the stem prior
to placing it into the planting medium.
Perlite and vermiculite make good medium. Rooting should occur within four to six
weeks. Keep your cuttings moist.
Hardwood plant propagation with deciduous plants occurs during their dormant season (after the plants have
lost their leaves).
Collect your cutting(s) from the wood of last season's growth.
Cuttings should be approximately between six and twenty inches
long. The diameter of the cutting should be between one and two inches. Use a rooting hormone on the end of each cutting, then bundle them together and place in a plastic bag, moist sawdust, or
peat. Keep the cuttings in a dark cool area.
The cutting can be planted outside as soon as rooting occurs.
Leaf cuttings are most commonly used for indoor plants including African
violets and Rex begonias. For African
violets use the entire leaf, leaf blade, or a portion of the leaf blade. Place the leaf cutting vertically in a rooting medium (perlite works well) after
applying a rooting hormone. The new
plant will form at the base of the leaf or at the midrib of a leaf blade. For plants with split leaves (e.g., Rex
begonia), start with a mature leaf from your chosen plant. Cut its large veins in the lower leaf surface and place it lower side down on the rooting medium. The new plant
should grow where the cut was made.
Both types of leaf cuttings should be kept under moist conditions, and the new plant planted when it appears strong and vital.
So, go forth and multiply. You‘ll save
money and have more fun. How often is
that possible?! Add to your flower beds
using cuttings from plants you already have and know do well on your site, as
well as try new plants via gift cuttings from fellow gardeners.
Layering
Layering is a propagation method which causes adventitious roots to form
on a stem still attached to a parent plant.
This process is so simple you might have caused it accidentally more
than once. Trailing blackberries,
raspberries, and gooseberries layer themselves naturally, as do morning glories. There are five layering methods. We’ll review only simple layering. Choose a plant with pliable, one year old
stems. Bend a stem to the ground and cover part of it with soil or a rooting medium. You might want to use a bent plant stake to
help hold the stem down where you want it. Leave the last 6 to 12 inches exposed and stake it into a vertical position. It is helpful to wound the underside of the stem that you are ‘planting’. Try this method with rhododendrons,
honeysuckles, and wisteria. Once roots
develop, carefully detach the new plant from the parent plant, and plant separately.
Separation
Separation is the process of propagating bulbs and corms. Bulbs (e.g., daffodils) and corms (e.g.,
gladiola) form and detach naturally.
Remove the newly formed bulbs and corms from the parent and plant separately.
Plant Division
Division is the process of cutting a plant into sections to
accomplish propagation. This is often
done with plants that have tubers, rhizomes, and tuberous roots such as
cyclamen, iris, and dahlias, respectively.
If a plant has more than one rooted crown, and the stems are not joined, pull the two crowns apart carefully, and plant separately. If the stems are joined horizontally, cut the stems and roots with a sharp knife, and plant separately.
Use some of the methods that have been reviewed in this article to
increase the beauty of your own garden, and maybe someone else’s,
by ‘gifting’ your newly propagated favorites.
For more information, call your Master Gardener Help Line.
University of California Cooperative Extension Master Gardener Volunteers can provide additional gardening information upon
request. Call the San Luis Obispo office at 781-5939 on Mondays and Thursdays from 1 to 5 PM, the Arroyo Grande office at 473-7190 on Wednesdays from 9 AM to 1 PM, or the Paso Robles office at 237-3100 on Wednesdays from 9 AM to Noon. The San Luis Obispo Master Gardener website is at http://groups.ucanr.org/slomg/. Questions can be e-mailed to mgsanluisobispo@ucdavis.edu.