Tropical Waterlily Season
by Charles B. Thomas
Images by Mark & Martha Prescott
Click to enlarge
At Pondapalooza 2006, I luckily ran into a friend I had not
seen for seven years. He astonished everyone he saw there with
exciting news for us tropical waterlily and Victoria aficionados.
No matter how many weeks tropical waterlilies bloom before
succumbing to the cold, we all would love a few extra autumn
weeks to enjoy them. Likewise, we all would love to start them
outdoors safely a few extra weeks earlier in the spring. How
could anyone accomplish this magic?
Enter Mark Prescott of Stephentown, NY USA. A long time lover
of tropical waterlilies, he operates a wholesale nursery in upstate
New York supplying a full line of aquatic plants to garden centers.
However, years of consumer resistance to tropical beauties perturbed
him. He could not overcome their reluctance. A short blooming
season and certain winter loss made tropicals unattractive to
Thermoplanter at Pondapalooza
Three years ago, Mark conceived the idea of warming soil to
stimulate tropical waterlilies to produce flowers more weeks
per season in outdoor ponds. He not only wanted to create a method
for himself, he envisioned a remarkable advantage for his customers
benefit one to overcome their disinclination to grow enthralling
Mark had discovered that soil temperature matters more than
water or air temperature. He found the trick is to maintain a
70-80 F. (21-27C.) microclimate around a lilys roots and
growth point. He soon designed a unique soil pot equipped with
a 70-watt heater. Named Thermoplanter, it allows USDA Zone 4 (temperature
water gardeners to start tropical waterlilies outdoors
the first week of May instead of mid-June.
His innovation encases a thermostatically controlled heater
in an inner pot. It uniformly transmits heat to soil in an outer
pot insulated to retain warmth. Why not use an aquarium heater?
An aquarium heater in an ordinary soil container results in hot
spots (burned roots) and a burned out unit.
Field tests in the summer of 2006 indicate
that Mark has successfully devised a way to stimulate extra weeks
of tropical waterlily blossoms at both ends of the season. Additionally,
he finds that his imaginative device works nicely for Victorias.
Late May - Early June
In 2005, Marks tropical waterlilies were happily blooming
May 7. Imagine! They flowered despite early May frost with air
temperature dipping to the mid 20s F. Water temperatures varied
from the mid 50s F (around 13 C) to mid 60s F (around 17 C) throughout
May. Nevertheless, his tropicals thrived splendidly.
After several autumn frosts or light ice coverage, Mark recommends
transferring tropicals with their Thermoplanters to a greenhouse
pool or a tank by a sunny window. After mid February, longer
days rouse them to begin new growth. In USDA Zones 7 and warmer,
Mark says the pots keep tropicals blooming (or at least surviving)
Mark has enlisted other water gardeners to independently test
his invention. So far, all of them report remarkable success.
Biology Professor Emeritus Dr.
Barre Hellquist has years of experience growing Victorias.
In the summer of 2006, he tried one in a Thermoplanter in his
Massachusetts pond. Viola! By mid August, he realized a breakthrough
with his first pre-September Victoria blooms after years
of effort. Another Victoria in the same pond without benefit
of a Thermoplanter lost the race with 13-inch leaves (33-cm)
and no buds by mid-August.
Earlier, when Barre planted his victorious Victoria,
he placed the Thermoplanter inside a ten-gallon (38-liter) pot
and filled it with soil. This greatly increased the insulation
factor. The plants soil was solely in the inner 2.5-gallon
(9.5-liter) pot. Only 6-8 inches (15-20 centimeters) of water
covered the top, leaving it the only non-insulated area of the
system. Mark calls this the Hellquist Method.
Barres Victoria flowered and produced 31-inch
(79-cm) pads despite low 60s F. (around 16 C.) day (low 50s [around
11 C.] night) water temperatures. The pot maintained an 82 F.
(28 C.) temperature, substantially warmer than the surrounding
pond water. The Thermoplanters warmth prevented cold shock.
It spurred the Victoria to flower in spite of adverse
cold water and air. Mark estimates Barres Victoria
used under US$4 worth of electricity -- much less expense than
heating the water.
Barre Hellquist's Victoria
'Longwood Hybrid' in Massachusetts in mid-August
Mark anxiously awaits results from England where The Royal
Horticultural Society and Professor Craig Baldwin of Sparsholt
College are separately conducting tests with four pots each.
With continued winning results, we anticipate that tropical
waterlilies will find much greater popularity in many places
where mild summer temperatures discourage growing tropicals.
Additionally, those who now grow tropicals in temperate climates
may enjoy extra weeks of tropical waterlily splendor. Thermoplanters should become generally available
This article is not an endorsement of this