Growing Victoria Outdoors
in The Netherlands
by André S.J. van Proosdij,
Scientific Keeper Hortus Botanicus Amsterdam
Click images to enlarge
History of Victoria
and the Amsterdam Hortus
In 1849 Victoria amazonica flowered for the first time
in Europe. This happened at the English estate of Chatsworth.
The size, beauty and fascinating story of Victoria made
many people want to grow a Victoria themselves. Several
tried to obtain seeds or plants. Within two decades dozens of
people succeeded in growing a Victoria from seeds to full
bloom. In 1859 the Hortus Botanicus in Amsterdam was the first
garden in the Netherlands that produced a flowering Victoria.
Since then, Victoria amazonica has been a special plant
in the Hortus. The flowering of this giant waterlily has always
attracted many visitors.
Similar to other botanic gardens, the Amsterdam Hortus too
had a special Victoria greenhouse in which a Victoria
was cultivated every year. In 1968 the old greenhouse had to
be closed as it literally fell apart and there was no money to
renovate it. In 1987 and 1993 Victoria amazonica returned
to the Amsterdam Hortus. In 1987 it flowered in a temporary plastic
tunnel greenhouse. In 1993 it flowered in the new three-climate
greenhouse. Unfortunately, the pond in that greenhouse is too
shaded, so flowering only occurred in the first year when all
the trees surrounding it were still very small.
In 2002 the Hortus tried to grow Victoria in a heated
outdoor pond. The first year Victoria amazonica was grown.
The plants were raised from seeds in an aquarium tank in a greenhouse.
By mid-May, the biggest was planted out. To keep the air above
the pond warm, the pond was covered at night with a plastic tent.
Unfortunately, water condensing on the plastic and dripping down
on the Victoria pads caused burned spots. Hence we removed
the tent and crossed our fingers that the weather would be nice.
Hard winds can damage the large pads and hail is a problem too.
Fortunately, the plant grew quite well without any protection.
It produced several flowers and fruits. In 2003 the experiment
was repeated successfully, this time using Victoria cruziana.
V. cruziana can tolerate lower temperatures than V.
amazonica and therefore is better suited for colder conditions.
For the past five years we have grown Victorias: in 2002 and
2004 V. amazonica, in 2003, 2005, and 2006 V. cruziana.
In 2005 the V. cruziana plant produced 30 flowers between
May 29 and October 16.
The picture at the right shows the outdoor pond. It measures
6 m in diameter and is approximately 1 m deep. On the bottom
of the pond is a 20-30 cm layer of sand and mud. In the pond
grows a lot of Elodea, Ceratophyllym and a Nelumbo,
providing well-stabilized aquatic conditions. The pond is warmed
by means of circular heating, connected to the heating system
of the adjacent greenhouse.
In the centre a one cubic meter container is situated. The
container is filled with a mixture of compost, sand and elephant
manure (Artis Zoo is nearby!). Throughout the growing season,
additional fertilization (Osmocote) is added. Water temperature
ranges from 28 to 30ºC (82-86ºF) and the pH fluctuates
between 6.5 and 7.5.
By mid-May, as the Victoria is planted out, the average
maximum day temperature is 17 to 20ºC (63-68ºF) and
the average minimum night temperature is 8 to 11ºC (46-52ºF).
The first flowers appear in late June or early July. New leaves
and flowers are produced until October. By then, temperatures
become too low for the flowers to open and autumn winds damage
The round pond in the Hortus' summer location
of Victoria cruziana.
Image by André van Proosdij / de Hortus.
The pond in winter.
Image by and © Yolente Verbeek / de Hortus
The mild and wet Dutch climate is strongly influenced by the
Atlantic Ocean and the North Sea. Temperatures are classified
in hardiness zones 7 to 8. Amsterdam, situated in the western
part of the Netherlands, 52º 22' N, 04º 54' E, fits
in zone 8. In addition, the microclimate in the city centre makes
temperatures in the Hortus slightly higher.
Outdoor Characteristics of Victoria amazonica and V. cruziana
Image by André van Proosdij / de Hortus.
Outdoor cultivated Victorias show some differences compared
to plants cultivated in a greenhouse. The leaves and flowers
of both Victoria species are a bit smaller compared to
plants grown in a greenhouse. The rims of the leaves are smaller,
too. V. amazonica leaves sometimes completely lack a rim.
V. cruziana, the leaves of which normally have a much
higher rim, produces a rim of 3-8 cm outdoors. Generally speaking,
V. cruziana grows slightly better and looks stronger than
V. amazonica. This is not surprising, as in nature V.
cruziana grows in areas less tropical than V. amazonica.
In the Hortus we prefer to grow V. cruziana, as our plant
is used for public display and simply has to look good.
The Hortus Botanicus in Amsterdam is the only garden in the
Netherlands that grows Victoria outdoors. It is very possible
to grow Victoria in an outdoor pond in the Netherlands
as long as one creates a situation that answers the plants' demands:
high water temperature, lots of sunlight and a rich soil. Covering
the pond at night is not necessary, although heavy wind and hail
can severely damage the leaves. Plants are smaller compared to
plants grown indoors.
In 2006 we tried to raise plants from seeds one generation
removed from the wild in Paraguay and Argentina. The parents
were collected from populations growing in relatively cold areas.
Hopefully, plants from these populations are better adapted to
the colder climate in which we grow them. Unfortunately, not
a single seed germinated. In 2007 we will try again. It will
be interesting to compare the Hortus Victoria results
with other outdoor Victoria outcomes in Europe and North
Website of the Hortus Botanicus Amsterdam