Tropical lilies are often thought of as a rather delicate plant in Colorado, best left to the 'experienced' water gardener. This is far from reality. With a little effort you can propagate and display your tropical lilies, year after year, as easily and reliably as you do your hardy lilies.

While there are some temperature constraints in the late spring, tropicals really do quite well in Colorado ponds, blooming well into September and often into mid-October.

Day and night blooming tropical water lilies should be planted in a 2-3 gallon pot. Fill the pot half full with a rich heavy garden soil and add 2-4 aquatic fertilizer tablets.Potting soil,compost, vermiculite, or perlite should not be used, as they float out and foul the water. Continue to fill the pot with soil to about 2" from the top.

The tuber should be set upright, in the center of the pot with the roots buried gently in the soil. Make sure the tip of the crown is at soil level. Firmly pack soil in the pot. Next, if desired add one-half inch to one inch of gravel to prevent the soil from escaping from the container and to keep fish from digging in the pot and uprooting the plant.

The plant can now be lowered into the water to a depth of approximately 6." As the plant grows, it can be lowered to a depth of 12." Tropical lilies cannot tolerate cold temperatures and should not be planted until the water reaches a temperature of at least 70 degrees. Planting too early can cause dormancy and restrict the potential growth of the plant. Tropicals bloom from late spring through early fall, depending on the weather. Fertilizer plants every 2 -3 weeks.

We have become accustomed to relegating them to the trash at the end of each season, and in doing so, kill off a plant that can be held over the winter as can the Gladiolus, Canna Lily, and other 'spring' bulbs, tubers, and corms from our conventional gardens.The investment of 5 or 10 minutes in the fall when you are preparing your pond for winter, and another 5 or 10 minutes in December or January, will yield you a tuber which can produce from 1 to 5 or more plants in the spring.

Here's how.....
Allow your plant to stay out in the pond until it stops producing flowers and leaves. This usually occurs in late September or early October, and perhaps later if your pond is especially warm. At that time pull your lily and allow it to drain for a day in a cool shaded area. Remove all dead and weak tissue, allowing only the smallest and firmest leaves to remain.

Place the pot in a plastic trash bag which should then be folded over loosely. Store it in a cool location (55 degrees is ideal). The purpose of the bag is to prevent the soil from becoming too dry. Check the soil periodically to assure it remains moist, but not muddy.

BLOOMS FOR NEXT YEAR
Around the beginning of the year, break open the soil ball and remove the tuber which has hopefully formed. Carefully clean the tuber of all loose debris and place it in a zip-lock bag with some water. Store the tuber in a dark location where the temperature is as close as possible to 55 degrees. Check it occasionally, rinsing and changing the water if it fouls.

In late March or early April, float the tuber, in the bag, in a container of water with a temperature of 75-80 degrees. When the tuber just begins to sprout, place it in a small pot (3" is fine), with a rich soil, and add light to the formula.

The type of light is not as important as you may think, but more and stronger is always better, and direct sunlight would be nice. An old fish tank with its heater and light will be adequate, but if you don't have one, improvise something. You will want 4"-8" of water over the pot for the lily to grow properly.

In a few days the leaves will appear above the soil. Allow the plant(s) to grow until the leaves are 1-1/4" - 1-1/2" in diameter. At that point, gently rinse the soil away and separate the small plants from the tuber, carefully retaining as many of the roots as possible while untangling the mess. Repot the tuber for more plants.

The plants are attached to the tuber by a stolon, or runner, which in the day blooming group is usually quite short, making it appear that they are attached directly to the tuber. In the night bloomers this stolon may extend several inches beyond the tuber.

Place these plants in 4" or larger pots and grow them until a significant number of roots begin to leave the pot. Then pot them up again, to any size you wish, and continue to do so as necessary until the pond warms, usually in the 1st or 2nd week in June.

Then a final potting into a 2-gallon pot full of any rich soil which does not float. Place the lily in your pond after covering the soil with an inch of gravel if you have fish.

You may now prepare to enjoy the next 5 to 6 months of the summer and autumn blooming season.

Viviparous Tropical Lilies
Some tropical lilies are viviparous ('live-bearing'), and only the species N. micrantha and its hybrids are viviparous.

Autumn is the season where viviparous growth is produced. The growths are located at the point where the stem joins the leaf and are evidenced by a 'growth' or bump at that point. This growth will produce from one to several genetically identical plants, and it is not uncommon for these growths to produce several plants which should be separated if possible.

Simply float these leaves in 75 to 80 degree water until the new leaves and roots develop (try floating them upside down), then pot and grow through the winter in bright light as you would a tuber sprout. In June plant in a two gallon pot and place in your pond and enjoy.

HINTS FOR SUCCESS WITH TROPICALS

1. Unless you have a GIANT pond, a 2-gallon pot is adequate for a tropical lily and will provide a specimen of 3'-5' feet in diameter, providing you fertilize with 2 or 3 aquatic fertilizer tablets every 2 to 3 weeks. The larger the pot, the less likely you will produce a tuber.
2. Prune your plant back to a 3' or 4'diameter every 2 or 3 weeks, at the same time you fertilize, taking the outer leaves, to keep it compact and symmetrical for best display and flower production.
3. Stop fertilizing the tropical lilies at the same time you stop fertilizing the hardy lilies (mid-August).
4. The hybrid blue, viviparous lilies, are usually the easiest to work with ('Blue Bird', 'Panama Pacific' and 'Tina' are excellent.), so try starting with them. In addition, the species lilies N. micrantha, N. colorata, and N. coerulea are quite tolerant of cooler water and less sunlight, and are an excellent plant to start with, as well.
5) Yellows are usually the least tolerant of the tropicals, yet 'St. Louis Gold' has performed in an outstanding manner under duress. In a 4" pot, with a temperature of under 70 degrees, one plant produced constant blooms over an entire winter inside a shaded greenhouse. It was not fertilized, re-potted, or catered to. It merely produced.
6) Do not attempt to plant the tuber itself. To do so will probably result in either a few spindly leaves without flowers, or a robust multi-crowned plant, with a multitude of leaves and few, if any, blooms. Plant a single plant per pot.
7) Experiment!!