Grow Gloexinias 
3144's or 4’s, and these size pots cannot 
possibly support full-grown  gloxinias 
without frequent but careful feedings, 
which is a source of trouble among 
many amateur growers. The shift from 
21%- to 5-inch pots is therefore a thor- 
oughly sound practice. 
After the July-sown plants have flow- 
ered during the following spring and 
summer, and by the time they go into 
their resting stage, or around October, 
the tubers should be from 2 to 3 inches 
in diameter. These tubers, planted in 
November, produce the largest specimen 
plants I have ever grown or seen. 
The most popular method of propagat- 
ing gloxinias is by leaf cuttings. This 
can be done in several different ways. 
Most amateurs root the leaves in water, 
but I would not recommend this prac- 
tice. I suggest one of two methods, de- 
pending on whether one wants several 
small plants or one large tuber to plant 
at a later date. If several small plants 
are wanted, place the leaf on damp 
sand in a terrarium or goldfish bowl, 
break the ribs of the leaf in several 
places, and cover the bowl until the little 
plants begin to develop. These should 
begin to form at the breaks in the ribs 
within a few weeks. 
If a large tuber is desired, use the 
same container and insert only about 2 
‘nches of the stem in the sand. Keep the 
bowl covered until the leaf has become 
established in the sand. The rooted leaf 
should be kept in the sand as long as 
possible. When the leaf turns yellow and 
dies, the tuber that has formed is ready 
for potting. The size of pot to be used 
will depend on the size of the tuber. 
Leaves rooted around June 1 should 
have tubers over 114 inches across by 
November, which could be planted di- 
rectly into 5-inch pots. The sand should 
be kept moist right up until the time the 
leaf dies and the tuber is ready for pot- 
ting. because if it should dry out the 
tuber would ripen and sprout before it 
had reached its peak size. 
For either method of leaf propagation, 
the leaves should be taken while they 
are still in good, green condition—that 
is, while the plant is still in bloom. 
If one wishes to acquire plants of a 
definite flower color, it is necessary either 
to propagate them from mature plants or 
else to purchase mature tubers. The size 
of the tuber has a direct bearing on the 
number of blooms it will produce, al- 
though small tubers started in Novem- 
ber and grown at a 62° temperature will 
produce better plants than those started 
from larger tubers in February or 
March. This is because there is a de- 
cided deterioration in the vitality of 
tubers after the first of February. 
I started my collection of gloxinias 
just before the war. I decided to try my 
hand at cross-pollinating some of the 
better varieties that I had, because I had 
found it impossible to purchase tubers. 
Black leaves are sometimes caused by 
handling wilted plants in hot sunshine. 
Fortunately, when I started, I had one 
really outstanding strain among the 
several that I had on trial. I now have 
over 50 distinctly different gloxinias as 
a result of selective crossing and re- 
crossing. Some of these, of course, are 
the named varieties which have always 
been popular, even though the blossoms 
of some are comparatively small. Be- 
sides the large, open-flowered kinds. they 
include also the slipper type. The flow- 
ers are like oversize foxgloves. 
Almost all of our large-flowered hy- 
brids have flowers over 5 inches in diam- 
eter. Many of these are ruffled. Some are 
in solid colors, ranging from shades of 
pink through deep red and from delicate 
shades of lavender through purple. 
Others are so finely speckled that it 
would appear that a mist of paint had 
touched them. Still others are of solid 
color with a speckled border of larger 
spots. Some are mottled and veined in 
various colors on a white background. 
In my breeding work, I do not try to 
produce gloxinias that come true to color 
from seed by pollinating flowers on the 
same plant. This practice results in a 
decided weakness both in the germina- 
tion of the seed and also in resistance to 
disease such as leafspot. My aim is to 
have an excellent assortment of colors on 
plants that are easy to grow. 
I have crossed a blue slipper type with 
a large speckled hybrid. The results in- 
cluded two dark slippers, several red or 
rose slippers, and a considerable num- 
ber of plants with little upright flowers 
of no particular value. The following 
year I had a red-speckled slipper and a 
purple-speckled slipper. These, as far 
as I know, are the only speckled slipper 
type gloxinias ever produced. 
Among insect pests, thrips are the 
only ones that are likely to give gloxinia 
enthusiasts trouble at one time or an- 
other. The first sign of their presence is 
a rusty appearance of the leaves, espe- 
cially underneath, and also of the stems. 
To keep thrips under control it used to 
be necessary to spray regularly with 
nicotine sulphate. Since DDT became 
available, however, their control has 
been much easier. By the use of DDT 
every six or eight weeks I think that 
trouble from thrips is a thing of the past. 
DDT should be used with precaution, 
and as directed by the manufacturer. 
Aphids can cause considerable dam- 
age. but they are easily controlled. Nico- 
tine sulphate is the most effective spray 
for all types of aphids. Mealybugs will 
sometimes attack gloxinias, but they pre- 
fer other plants. I have never been trou- 
bled with cyclamen mites, but I have 
been told that they can be a stubborn 
pest. However, the new parathion sprays 
are reported to afford positive control. 
There is some confusion regarding 
spots on gloxinia leaves and also re- 
garding leaves suddenly dying. There 
are various causes of these troubles, some 
of which are not understood. Some 
strains are very susceptible to having 
their leaves turn black for no apparent 
reason, and plants whose buds blast eas- 
ily are also apt to be weak in this re- 
spect. Handling somewhat wilted plants 
when the sun is hot will often cause them 
to turn black. Cold water splashed on 
the leaves of a plant in a warm, sunny 
window can cause the same damage. 
After the plants recover, the leaves have 
burned-looking spots on them. Some- 
times it is merely the surface of the leaf 
that has had the tissues broken by a 
sudden change of temperature, but often- 
times the injury penetrates the whole 
thickness of the leaf. This kind of spot 
never spreads, and quite often the color 
will return to leaves that have suffered 
only slight surface injury. 
Another kind of leafspot is enirely dif- 
ferent, since it is caused by a disease and 
therefore spreads, especially in cloudy 
weather when the humidity is high. 
Water on the leaves will also spread the 
spores of the disease from one leaf to the 
next. The only preventive measure I 
have found for this leafspot is to supply 
sufficient ventilation so that moisture does 
not form on the leaves. Also, any leaves 
that appear to be in a decaying condi- 
tion, especially if they appear to have 
mold on them, should be removed and 
burned, 
Reprinted from FLOWER GROWER, November, 1949 
