Figure 1 -
On the left is a close up of the plant in the pot
in late November 2013 showing the ice at the base of the stem. At this time
some of the bark and leaves of the plant are still present. On the right is the same plant two weeks
later after a thaw and new ice had formed.
In this photo the bark and leaves have been stripped off the stem
and the ice is smaller.
I found it
interesting that this ornamental had some ice, and I liked the
flowers. So, in spring 2014 I bought
five plants from my local nursery and placed them in two places in my
yard. The two pink ones grew to about
18 inches (45 cm) tall. The three
red ones were not as tall or full, probably because they were in a drier
site. They grew to a height of about
13 inches (33 cm).
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Figure 2
- Cluster of two pink Pentas about 18 in (45
cm) tall on left and the group of three, shorter red Pentas
on the right.
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In early
November 2014 I had the first formation of ice on plants in the yard. To my surprise the Pentas
had very good ice. Actually, I should not have been surprised because in my
correspondence I have some photos of ice on Pentas
sent to me by Jan MacDougal of Charleston, South Carolina. The ice I had is consistent with that in
her photos.
It is hard
to compare the Penta ice to that on the Verbesina virginica stems because
the Verbesina
stems are straight and unbranched while the Pentas
have many branches starting at the base of the plant. It is my impression that the ice on the Pentas was more full, and
extended over a greater proportion of the total length of stem, than on any
of my Verbesina
stems.
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Figure 3
- Ice on the two stems of pink Pentas in the
front yard. This was November 12
and before this date I had cut off the leaves of the plant on the right
so I could see the ice. The plant
on the left still has its leaves and it is hard to see the ice. In the case of the plant on the right,
note how ice is formed on all of the branches of
stems.
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The ice on
the three stems of the red Pentas was not as easy
to observe because the plants were smaller, in a mix of other plants and
the leaves were dense. In the left
photo below one can see lengths of white ice extending off in many
directions, all on the same plant.
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Figure 4
- On the left ice forms bright white rods along a
number of stems that extend up and to the right from the base
behind the tag. Here we see how
the ice has peeled back the bark off the stems. After the ice melts the bark falls off
or is easy to remove. Note the tag
identifies this as the Butterfly Deep Rose variety of Penta. I call it red. On the right is ice on two cutoff branches
of the neighboring Penta. These
are about 2 inches (5 cm) long. On
these I removed the bark when I cut the stems exposing the woody
stalks. Obviously, the ice forms
on the woody part of the stem and not on the bark.
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Refrigerator experiments with Penta
stems
Years ago,
I found a way to grow ice on small pebbles in a refrigerator
with some success. A couple of times
I had tried to grow ice on dead plant stems with no success. Then this fall I inserted green stems of Verbesina virginica in my
refrigerator setup and to my surprise grew ice flowers. When I found ice on the stems of Penta in
my yard, I cut some stems and put them into my refrigerator setup. More success.
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Figure 5
- The ice chest above serves to provide an environment where I can grow
ice at any time in a refrigerator.
The ice chest and peach colored foam provide insulation from the
cold of the freezer. The small
plastic container in the center is filled with wet sand and plant stems
are pushed down into the sand.
Below this plastic container is a light bulb which provides the
heat source to keep the water in the container liquid. When adjusted
properly the temperature of the air above the sand is below freezing but
the water in the sand remains liquid.
On the right I am holding a small stem of Penta that was in the
sand. The ice grew on that portion
of the stem above the sand through the process of ice segregation. Normally, I let this setup run for
about 24 hours.
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I check my
refrigerator setup every day or every other day. I have not been in a
position to see how many hours are required to get good ice. The temperature of the air in the freezer
varies around 14 F (-10 C). As discussed
on my Pebble Ice page ,
the temperature in the freezer varies as the freezer cycles on and
off. That cycling sometimes produces
waves or ridges in the ice.
I am now
conducting many experiments with different plant stems. By the time I
discovered I could get good ice in the refrigerator with green plant stems
the growing season was near the end.
I am looking forward to next year to try a variety of stems at
various stages of growth.
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Figure 6
- In this setup I have one piece of Verbesina virginica in the center
and pieces of Penta stems at the four corners. The Verbesina stem
is much larger in diameter and not surprisingly the ice flower is
larger. But the ice flowers on the
Penta stems are distinct and voluminous.
The example in the upper left is quite large on a stem that has
become fractured.
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Based on
this limited opportunity to see the products of ice segregation on the
stems of five Penta plants in the past month, I am extremely pleased. I will be growing Pentas
again next year and will be more prepared for the presence of ice as cold
weather moves in. And I want to
harvest green stems over the summer to put in my freezer to see if and when they support the growth of ice flowers.
When
people ask where they can find plants which produce ice flowers, I wish
them luck. I brought seeds into my
yard for Verbesina virginica and that is
where I have found my ice flowers. I
have tried to find other plants and have had marginal success. Now I can tell everyone to purchas Pentas to enjoy the
flowers in the summer and observe the ice flowers in late fall. I know there are other plants that
produce such ice but we have not examined them
thoroughly.
Why do a few plants produce ice
flowers and most do not?
I have
been looking for an explanation to this question by looking at my stems of Verbesina virginica. I have access to four types of Verbesina
and only one of them produces ice flowers.
The stems of these four types of Verbesina are
very similar so why does one produce ice flowers and the other three do
not? Now, I find the Penta stems
produce ice flowers and those stems are distinctly different from all of the Verbesina
stems.
And, in
the last month I have found some small plants in my yard that appear to
produce ice flowers. I want to do
more work with those stems before I say anything more. I am looking for green stems of many
plants next summer to test in my refrigerator setup.
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