They won't grow in the ground, they need some water. Growing naturally they spread out when wet season rains allow them to grow into new areas. But come the dry season and the water drops down those in just soil die back to the roots. If that soil dries the roots die. The Lotus grows in up to about 2 metres depth of water. If your pond is shallower than that then they'll take over quite quickly in the growing season, especially if the climate is warm.

We live in zone 4 southern end have raised lotus for many years in 24" X8" shallow tubs. We store the tubs in one of our lined ponds for the winter as the main one drains out. They need about 10-12" of water over the soil in the container to winter in our climate. We haul them out in the spring and put them in a warmer location outdoors, not back in the earth pond as the water is fairly cold especially in springtime. After they have a few airborne leaves (not resting on water surface like a lily pad) you can give them fertilizer tabs. Remember to keep the water to a depth of 5-6" over the soil. Plant tubers w/ about 1" soil over them, weight them down with a rock and DON"T cover the growth point. The tubs have 3"-4" soil in them. I wouldn't plant them in the pond if you want to do anything else with the pond as the stems are very spiny. If you're in a warmer climate I would guess they'd own the pond quite quickly. Ours never get big enough to eat, but the flowers and pods are attractive. Good luck.

You may want to check this page for growing lotus in pond.

http://www.hydrangeasinthenorth.com/tim-s-lotus-ponds-and-how-to-build

Beautiful! I want one. What zone?