Growing Australian Water Lilies is about the same as growing tropical water lilies however they tend to go dormant more quickly. Here are a few suggestions that may help you nurture the Aussies.
If you have purchased an Australian Water Lily it must be planted as soon as possible into fertilized soil and placed in water at least 75-80 degrees F. The water should be about 4-6 inches over the pot or less if the plant is small. As the weather turns cooler the plants may become dormant and form a tuber. This tuber should be placed in slightly moist peat moss, if you can squeeze water out of the peat it is too wet. Place the tuber in the moist peat and store in a Ziplock type quart bag tightly sealed and without added water. Label the bag and store indoors at 65-70 degrees F.
Three months before water lilies generally grow well in ponds at your location, wash the peat off the tubers and place in a clean Ziploc bag with non-chlorinated water leaving air space so the bag will float. Place the bag into a tub of heated water using an aquarium heater to keep the temperature at 80-90 degrees F. Place in natural daylight or under a grow light turned on for 12-14 hours. It may take 3 to 8 weeks to produce rooted plants.
When the tubers have roots and small plants it is time to plant in fertilized soil in a 4 inch pot. Place the pot in water at least 70 degrees F. (warmer water yields faster growth) and check weekly for roots coming out of the pot. At this point transplant into a 6 inch pot with fertilized soil. If the plants become cramped or runs out of fertilizer they may go dormant. Finally plant into a 10-12 inch pot when roots escape the smaller pot.
The fertilized soil can be a mix of top soil in a 6 inch pot and mixed with a handful of peat moss and one full tablespoon of 13-13-13 or 13-8-15 fertilizer. When planting into the 10—12 inch pot add about 4 tablespoons of fertilizer in the bottom half of the pot of soil mix.