Aquatic Plant Care by Zone

Zone 3

Zone 3 Plants are hardy from -30 to -40 degrees F. These plants will winter well on the plant shelves where they have been growing all summer. Little care is needed to protect these plants from the cold. They will be the first to show their heads in the spring. Most of these plants will bud and start blooming before the rest of the plants in your pond will show new growth. Care must be taken in raising these plants to the plant shelves if you have stored them in the bottom of the pond for the winter. Keep in mind the water temperature at the level you have stored the plants and do not move them up into air temperature that is still below freezing. Doing so will damage the tender new growth the plant has started and will kill or set the plant back. If they remained on the shelf all winter, just let them do their thing.

Fertilize the plants first thing in the spring when new growth appears. Wait to divide or repot the plants until they are established, growing well and have gotten past the winter shock. Dividing or repotting too soon can cause damage to the root system and the plant may die.

Zone 4

Zone 4 plants are hardy from -20 to -30 degrees F. In most locations except zones 2 and 3, these plants will winter right on the plant shelf, with no special care. They will be the first to show their heads in the spring. Most of these plants will bud and start blooming before the rest of the plants in your pond will show new growth. Care must be taken in raising these plants to the plant shelves if you have stored them in the bottom of the pond for the winter. Keep in mind the water temperature at the level you have stored the plants and do not move them up into air temperature that is still below freezing. Doing so will damage the tender new growth the plant has started and will kill or set the plant back. If they remained on the shelf all winter, just let them do their thing. Follow the repotting or dividing instruction found in the Zone 3 description with these plants as well.

Zone 5

Zone five plants are hardy from -20 to -10 degrees F. In planting zones 2, 3, and 4, these plants should be placed lower in the pond. In zones 5 or warmer, little protection is required in the winter time. Although some of the zone 5 plants are a little tenderer than others. Most will winter very well in colder climates.

Zone 6

Zone 6 plants are hardy from 0 to -10 degrees F. Protection from extreme cold is requires in planting zones 2, 3, 4, and 5. In these planting zones, lower all of your zone 6 plants to the bottom of the pond for winter protection and be careful not to raise them to the plant shelves into air temperature that is still freezing. Patience is the key for starting these plants in the spring. Divide or repot only after the plant is vigorously growing to avoid unnecessary shock.

Zone 7

Zone 7 plants are hardy from 0 to 10 degrees F and are considered semi-tropical. They are either brought in during the winter months or considered annuals in plant zones 2, 3, 4, and 5. Some of the hardier zone 7 plants will winter in the bottom of the pond in zone 5 areas, this will be a trial and error proposition. If you are not sure, it is best to bring the plant indoors, if this is not an option try wintering in the bottom of the pond. You may get lucky! Raise Zone 7 plants up from the bottom of the pond only after all danger of frost is past. Waiting until the night time temperatures are above 40 degrees is the best.

Zone 8

Zone 8 plants can tolerate temperatures no lower than 10 to 20 degrees F. These plants are considered tropical plants in planting zones 2, 3, 4, 5, and 6. Some may be wintered in the bottom of the pond where the water temperature remains in this range or warmer. In colder climates it is best to either bring the plants in or treat them as annuals. Some of these plants will survive indoors better than others. The Lily-Like tropicals are more difficult to winter indoors (not in a greenhouse) because of their light requirements. Treat the majority of the zone 8 plants as annuals. Water cana and taro can be wintered as bulbs like gladiola and started indoors in early spring. If you winter this way and start the plants again in the spring, be sure that the night time temperatures are well above freezing and that the new start is properly hardened before placing in your pond.

If you wintered these plant as bulbs, do not be in too big of a hurry to start them indoors. These plants need a night time temperature above 45 degrees to perform at their best. Any colder and the plant thinks it is winter and will not flourish.

Zone 9

Zone 9 plants can tolerate temperatures no colder than 20 to 30 degrees F. In all planting zones from 2 to 7 these plants should be brought indoors or treated as annuals. In some of the very cold zones, these plants will not perform to their up most ability. In colder zones, they will not be as tall or as full. Care must be taken as to the night time temperatures and placed outdoors in the spring accordingly. Usually 45 degrees signals these plants that it is the dormant season. Zone 9 floating plants are more difficult to winter indoors. Due to their minimal cost, most people simply replace them each year.

Zone 10

Zone 10 plants are hardy to 30 to 40 degrees. They are true tropicals. In all planting zones from 2 to 8 these plants should be brought indoors or treated as annuals. In some of the very cold zones, these plants will not perform to their up most ability. In colder zones, they will not be as tall or as full. Care must be taken as to the night time temperatures and placed outdoors in the spring accordingly. Usually 45 degrees signals these plants that it is the dormant season. Be sure to harden off gradually in the spring as these plants can sun burn and wind burn easily.