By Iwein Coppens, August 2004
In this article I would like to share some growing experience concerning
temperate Pinguicula. These Pinguicula species are to be found in
relatively high regions of the Alps, the Jura mounts and the balkan region. The
method I am going to describe is based on the well known dripping wall system,
but is more simplified and does not require special installations.
These temperate species have two different growing periods. In summer they
expose a carnivorous rosette of leaves. However in by the end of the growing
season, these leaves completely disappear and the plant survives by forming a
hibernaculum. These hibernacula are an excellent way of propagation. After two
or three growing seasons such a hibernaculum grows into a mature specimen that
will flower, provided enough sunlight was present in the previous growing season.
Flowering will occur in the beginning of the growing season. Mature plants often
expose more than one flower.
experimental method for cultivation :
In general carnivorous plant literature will specify these temperate Pinguicula
as difficult to keep in long term cultivation. Contrary to what is usually
told, I believe that it is quite simple, if some rules are kept in mind.
Therefore I would like to share my experience. The species I have successfully
tested are: Pinguicula grandiflora, P. grandiflora x fiorii, P balcanica,
P.vallisneriifolia en P vulgaris var. bicolor. The only one that didn’t
survive was Pinguicula vallisneriifolia.
As these species grow in mountain regions, soil often consists of rocks, bonded
together with organic matters. Keeping this in mind I wanted to try growing
these species not in a pot, but on a rock stone. The pores of the stone were
filled with a mixture of organic matters, soil, loam and perlite. The advantage
of this method to the dripping wall is that one doesn’t need a special purpose
So, what kind of rock was used in the experiment? I went to some specialised
garden centres looking for suitable rocks. the sheer amount of different rocks
The ideal rock would contain several crevices. Every crevice is a possible
location to put a plant. It should also have a lot of pores which could draw
water by the capillarity effect. The small pores will allow the soil to be moist,
even if the rock is not watered from above. for this test I have prepared two
different typed of rock. First one is a sandstone based rock, and another has
more structure of so called lava rock.
Before planting the plants in their definitive location, it is recommended to
keep the prepared roc in a tray with a couple of cm water. This period can be
used to check if the water reaches all desired locations, without need for top
watering the rock. During this period the rock can be started up with some
mosses to give it a weathered effect. During this testing period is became clear
that the sandstone rock is more difficult to keep moist, and that some crevices
needed an extra soil bridge to a moist area.
The planting with Pinguicula was done in early spring. Hibernacula of different species were placed in groups on the rocks (See picture 1 below) .
Picture 1 : Pinguicula grandiflora and Pinguicula vulgaris winter hibernacula.
Photo : Iwein Coppens
On the sandstone rock I planted different species together: At the top, 6 small Pinguicula grandiflora hibernacula were planted at a distance of 4 cm each. During the second growing season on the rock it became clear that this was far too close to each other. I didn’t imagine that the plants would expand so quickly. They even flowered (see picture 2 and picture 3 below).
Picture 2 : Pinguicula grandiflora nearly to flower.
Photo : Iwein Coppens
Picture 3 : Pinguicula grandiflora in full bloom.
Photo : Iwein Coppens
At the left sloped edge I placed two specimen of
P. vulgaris var. bicolour. Although P. vulgaris is said to
be much more difficult, even these plants showed a first flower in the second
On the other slope following species were planted: P. balcanica, P.
vallisneriifolia and the hybrid P. grandiflora rosea x fiorii. These
plants didn’t flower yet. As these have expanded their rosette and
hibernaculum after the second growing season was definitely bigger than before,
I have good hope they will flower in future seasons.
However not all ended good. My only two plants of P. vallisneriifolia
have dried out suddenly and have sadly disappeared.
The second rock I have planted only one species. Pinguicula balcanica. (see
picture 4 below)
Picture 4 : Pinguicula balcanica
Photo : Iwein Coppens
It soon became obvious that this rock has a much better transfer of moist from
rock to the adhered soil. Mosses have already covered a large part of the
surface. Due to favourable conditions, the P. balcanica are doing well
and the biggest plant even flowered. The P.
balcanica’s I grow have white
flowers with a slight impression of pink.
Both rocks are in an unheated greenhouse. The greenhouse doesn’t receive full
sun until late evening. During the growing season the rocks were placed in a
couple of cm water, just enough to keep the surface of the soil moist. During
the winter, I have kept the plants outside all the time. The rocks were placed
in an insulated box, covered with a glass lid.
During winter the amount
of watering was very small. At
the end of the winter season the rocks appeared bonedry. I have had no losses
due to this dry treatment in winter. All plants that had formed hibernacula
before winter, had survived very well.
If I compare surviving rates of plants cultivated in separate pots to these of
plants cultivated on the rocks, my experience is that plants in separate pots
are more vulnerable.
of the experiment :
Keeping temperate Pinguicula appears to be less difficult than it is told.
Although some rules have to be applied.
A good balance in the moisture levels is needed during growing season and during
winter. Too much water in winter will cause the hibernacula to rot. In summer
plants seem to be impossible to recover when soil dried out.
Also the days of good weather in late winter are dangerous. Plants tend to start
growing too early and can be surprised by late frost. For this reason some
people keep the hibernacula in the refrigerator until the risk of frost is gone.
In this experiment I have kept plants outside during winter, shielded from rain.
Rocks and soil were completely dry during winter season. I imagine that these
dry conditions prevented the plants from starting too early.
Also the summer has some difficult days. The hottest days make the plants suffer.
We shouldn’t forget that these temperate plants are naturally growing in
mountain area’s, where even at full sun, temperatures are not as high as in
the average greenhouse.
It seems that this growing method is quite
as good, if not more successful, than keeping plants in separate pots. However
during the 5th ICPS expedition I noticed that the actual natural
habitat of temperate Pinguicula is still different.