The real gardener derives his satisfaction from his ability to nurse plants along every step of their growth to their ultimate flowering glory. However, the greatest thrill is enjoyed by those who have succeeded in coaxing bloom from one of the plants considered difficult for the average gardener. Such a plant is the poinsettia (Euphorbia pulcherrima). Actually it really isn’t hard to grow, even though it can be temperamental.
There is one feature about this
traditional Christmas flower that sets it apart
from many other holiday flowers. Barring neglect
or accident, it will always be in full bloom for
Christmas in the latitude of New York City without
the gardener’s having to resort to any special
treatment, provided the plant does not receive
any light in addition to natural daylight.
The two most important factors in the successful flowering of poinsettias, and those, which make it temperamental, are temperature and humidity. The temperature must be as uniform as possible and must never drop below 60°F. The humidity should be kept high-60 to 70 percent. This is higher than it is possible to maintain in the average home so extra provisions may have to be made such as setting the pot on a tray filled with moist coke. Of course, if you have a greenhouse, which you run at 60°-65°F., the problem is much simpler.
Poinsettias are grown from cuttings.
These are taken from stock plants, which are carried
bone, dry over the winter. These can be plants
you get from your friends at Christmas. Place
them in a dark, cool cellar where they will dry
out and become dormant. Watch out for mildew while
the plants are dormant; if it shows up as a white
or brown powder, dust with sulfur. In April cut
the plants back to a point just above one of the
dormant buds on the stem.
Repot in new soil, water thoroughly,
and place in full sunlight. I use the same soil
for all stages of poinsettia growth, made up of
equal parts of compost and sandy topsoil sifted
together with several handfuls of superphosphate
added to each bushel of mixture. I add a shovelful
each of sand and peatmoss to each six shovelfuls
of the first mixture.
A better practice is to wait
until late July or early August to take cuttings,
and then, after the rooted cuttings are 6 to 8
inches tall, they can be potted up (three to an
8-inch bulb pan) and grown without any pinching.
There is no trick to preparing
cuttings. Cut the tip 4 to 6 inches with a sharp
knife. A white, sticky juice will exude from the
cut ends, but if the cuttings are immediately
dipped in a root hormone powder and placed firmly
in moist rooting medium, they will suffer little
setback. Many rooting media are recommended for
propagating poinsettia cuttings, but I have had
the best success with washed mason’s or builder’s
sand.
Before long new growth will appear
and cuttings may be taken any time after the shoots
are 6 inches long. The earlier the cuttings are
rooted the taller will be the blooming plants.
Cuttings taken any time up to the middle of June
should receive a soft pinch-removal of the top
half inch of terminal growth-when the plants are
about 1 foot high. In no case should plants be
pinched after the first of September or the resultant
new growth will be too short to make a well-shaped
flowering plant. Each of the two or more shoots
developing from the soft pinch will produce a
flower, but obviously the more flowers per plant
the smaller each will be. The taller plants produced
from early cuttings also have a bad habit of losing
their lower leaves.
The first two weeks are the most
critical in the life of the poinsettia. It is
here that the high humidity is needed to prevent
leaf wilt. Some growers invert large glass jars
over the cuttings, but I prefer to keep the cuttings
uncovered in a propagating bench in the greenhouse,
automatically watered from below.
The cuttings should be removed
when a good root system has developed and then
the plants should be firmly potted in 3-inch pots.
While the plants are getting established I like
to bury the pots up to the rim in sand kept moist
by the same system used in the propagating bench.
Another method I have used to obtain the same
moist conditions is to place the pot containing
the plant in the next-sized pot and filling the
space between the pots with sphagnum moss. If
the moss is kept damp the plants will never dry
out, nor will they be water soaked. You can also
bury the pots outdoors in a protected and partially
shaded spot in the garden, but check ever so often
to see that the roots do not grow through the
drainage hole.
As soon as more roots have developed,
shift to a 4-inch pot, or use three plants to
an 8-inch bulb pan. I believe poinsettias, like
many other vigorous growing shrubs, bloom better
when pot-bound; so I make this final shift by
the middle of October and keep the amount of new
soil added down to a minimum. Extra food can be
supplied by using your favorite liquid or dry
plant food at biweekly intervals after the plants
are established in their final pots.
Tall plants will require staking
and tying to keep the stems straight, but even
the smaller plants will be shaped better if, small
bamboo or metal stakes are placed alongside each
stem. Either pieces of pipe cleaner or paper-covered
wire plant ties can be used to tie the stems to
the stake.
If you have grown your plants
outdoors all summer, bring them in the house early,
before the temperature drops below 60° F,
and while the air in the house is still quite
humid. Use. a watertight, coke-filled tray with
the pots resting on a platform above the coke
to increase the humidity about the plants. Better
still, if you have a special room for houseplants
with a good sun exposure, purchase a fan-type
humidifier and you will find the air more healthful
for both the plants and your family.
By the first of December the
top leaves will begin to turn red. Incidentally,
the red leaves are not the flowers, but are merely
colored leaf bracts, which surround the tiny flowers.
Also, while red is the traditional poinsettia
color, they may be had in white or pink. After
Christmas, withhold water gradually and start
the cycle again.
By D. Leeth
Frederick Leeth
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