Water Gardens – Planting a Waterlily Pool
Water lilies are easily grown. The three requirements for their successful culture are: plenty of sunlight, rich soil and quiet, shallow water. The spread of an average lily is 10-12 sq. ft.
• Hardy lilies may be planted from May until September, but May and June are best months. Tropical lilies should not be set out until after the first week in June. Earlier planting is not safe as dormancy may result.
• Your pool should not be drained to plant tropical lilies. Plant in the water that has stood in the pool – fresh cold water will chill the plants and may cause dormancy. We recommend planting the lilies in tubs or wood pails, allowing at least one cubic foot of soil for each root, more if possible. A tub 24” across and 12” deep
makes an ideal container.
• Heavy clay loam is preferred, although any good garden loam is satisfactory. Do not use commercial potting soil, or add sand and peat to the mixture. Fertilize according to directions with water lily fertilizer. Well rotted cow manure may be used, but has a tendency to discolour the water and encourage algae growth.
• The plants should be set so that the crown, from which the leaves grow, is even, or slightly above the surface of the soil. It is advisable to sprinkle gravel or stone on top of the soil to prevent the fish from disturbing the soil and discolouring the water.
• The lilies should have from 6 to 12” of water over the soil or crown of plant; the best depth is 8”. In deep pools, use supports to hold the boxes up within approximately 8” of the surface of the water. Boxes in which the lilies are planted can easily be set without draining the water from the pool, in fact, it is better to use this method, as water that has been standing is usually much warmer than a freshly filled pool.
• Hardy lilies need to be fertilized each spring and throughout the growing season. After two to three years, the rhizome may need to be divided. Replant the best crown and pot up the smaller plants separately if space permits.
• Many people believe that running water in a lily pool is to be preferred. This is not the case. Water lilies and
aquatic plants do best in still water. Do not plant close to fountains and waterfalls.
Winter Pool Care
If the pool is deep enough, hardy plants may be lowered to the bottom of the pool in late fall. Additional protection may be added by covering the pool with boards and placing garbage bags of leaves or straw on top. Small pools may be covered with sheets of Styrofoam. Stock tank heaters are sometimes used to keep a small area of open water for gas exchange. This is especially important for fish. If the pool is too large to cover with boards, drain the water, place lily tubs in a corner of the pool and protect with leaves, straw or soil. Or, the tubs may be taken into a cool basement and kept covered with moist burlap. Do not allow the plants to become dry, more roots of hardy lilies are lost in winter by being kept too dry rather than by being frozen. Tropical lilies are best treated as annuals.