Water lilies are aquatic plants that can add beauty and interest to a backyard pond or water garden. Here are some general guidelines for planting water lilies:

1. Timing: Water lilies are typically planted in the spring, after the water temperature has reached around 60-70°F (15-21°C). This usually occurs in late April or early May in most regions. However, you can also plant them in the fall, as long as you have at least 4-6 weeks before the first frost.
2. Location: Water lilies need plenty of sunlight to thrive, so choose a location in your pond that receives at least 6 hours of direct sunlight each day. The water should be at least 18 inches (45 cm) deep, but not deeper than 4 feet (1.2 m).
3. Planting: To plant a water lily, start by filling a planting basket with a mixture of aquatic soil and gravel. Place the lily tuber (or rhizome) on top of the soil, with the growing tip facing up. Cover the tuber with another inch or two of soil and gravel, making sure not to bury it too deeply.
4. Maintenance: Once your water lilies are planted, you will need to maintain them by fertilizing them regularly with aquatic plant fertilizer, and removing any dead or yellow leaves. Water lilies should be pruned back in the fall to prevent excessive growth and ensure healthy growth the following spring.

Overall, planting water lilies can be a fun and rewarding project for any water garden enthusiast. With the right care and attention, your water lilies will bloom beautifully and enhance the natural beauty of your pond or water garden.