Whether you have just finished installing a new water garden or you are in the planning stages, you must decide what type and how many plants you are going to install.
Aquatic plants aren’t just used in the water garden to provide beauty and naturalization – they also serve the very important function of helping to balance the pond ecosystem. Their valuable biological filtration helps remove nitrogen, ammonia, nitrates, and other minerals that algae would otherwise feed on. In addition, the plants provide food, shade, and protection for the fish and wildlife that live in and around the pond. Typically, they are divided into four groups – water lilies, marginals, floating plants and submerged plants.
To pot or not to pot Planting Pots
Go natural when planting your marginals or lilies. Planting pockets help you hide those pots. If you have excavated your pond properly, you would have created planting pockets. If not you can create them with rocks right on the liner. Place pot into the pocket and cover with rocks to hide the pot.
Marginals can be planted right into the rock/gravel on the shallow shelf. If you have to plant in a pot look for the soft basket type of planters which are available on our website. They are light weight and can be easily tucked into areas.
Remember you want to achieve about 60% coverage of your pond surface with plants. Below you will see a recommended amount of plants to put into your water garden.
Lilies and marginals are perennials and will with care will return year to year.
4×6 to 6×6 pond
3 Water Hyacinth* (floating plants) treated as an annual plant
24 submerged plants
6×11 to 11×11 pond
6 water Hyacinth*
44 submerged plants
11×11 to 14×16 Pond
3 Hardy Lilies
8 Water Hyacinth*
90 Submerged plants
16×16 to 16×21 pond
12 water Hyacinth*
1 Lotus (keep in pot)
160 submerged plants
21×21 to 26×26
15 Water Hyacinth*
1 Lotus (keep in pot)
200 submerged plants
Next step is to determine which plants are you going to use.
Marginal plants are the largest aquatic group of plants and contain both perennial and tropical plants. These plants are planted on the top self of the pond. Most of them are true perennials and will come back year after year. They are called “marginals” because they typically grown around the edges of a pond or lake. Marginal plants thrive in wet soil or standing water that covers the crown or base of the plant by as little as two inches to as much as six inches.
Some of these plants are more invasive in warm climates so make sure you ask the garden center. Here’s some of our favorites:
Iris comes in many varieties. Do not plant the large yellow ones as they are very invasive.
Pickerelweed – This plant has glossy leaves and comes in pink or purple and is native in most climates. May need to be divided every 3 years.
Rushes – There are many kinds of rushes. Look for one that does well in your area and pick a size that matches the size of your pond.
4 Leaf Clover – This plant stays small in height but spreads in the water with beautiful 4 leaf clovers.
Sweet Flag – is a beautiful yellow/green strip leaf. Does not flower. Very hardy.
Lizard Tail – stays compact and has white flower.
Hose Tail Rush – native to several area. Very distinct dark ring circles on leaves. It comes in a dwarf variety.
Arrowhead – is a native plant and has leaves shaped like an arrowhead with small flowers.
Dwarf Papyrus, Dwarf Umbrella Palm, Taro, Blue Bells, Canna (note they now have a virus so we discourage you from growing these)
Invasive plants to stay away from
Chameleon Plant has been known to grown between liner and seal of biofalls created a leak. Keep away from any parts of the pond. Very invasive.
Cattails – Only grow in a pot where you can control them.
Lotus – Only grow in a pot and carefully watch for overgrowth. But is a beautiful plant with a gorgeous bloom.
Floating Hearts – will continue to replant in many areas of the pond. A little invasive.
There are hardy and tropical lilies. Hardy lilies are reliably perennial from the northern reachs of Zone 3 to the subtropical areas of Zone 11. The white, pink, red, or yellow flowers float directly on the water surface and will open during the day. When cold weather comes, the foliage dies. This should be removed before winter. New leaves emerge again in the spring.
Fertilizing lilies is necessary to encourage a greater number of large flowers. Time released granular fertilizer mixed into the soil at the bottom of the pot or plant pocket is a great way to fertilize lilies at the time of planting. Otherwise, use the fertilizer tables. Fertilize once a month during growing season.
Match the size of the lily to your water feature. Some grow to 10 feet. Look at the zone where they will stay hardy. Some bloom more profusely than others and they always need 4 to 6 hours of light.
Colorado – blooms very well peachy color
James Brydon – red to pink smaller flower
Perry’s Almost Black – red with pink edges larger flower
Attraction – Red with yellow center
Marliacea Chomatella – yellow
WHAT IS THE MOST PRODUCTIVE HARDY LILY I CAN PLANT?
It is a red hardy lily. It can bloom with 10 flowers at the same time.
It’s name is Laydecter/Fulgens.
These lilies take water temps in the 70s. The flowers of tropical water lilies sit above the water and come in the typical whites, yellows, pinks and reds. Unique to tropical lilies are the blue shades – light blue to deep purple. Flowers are also more fragrant and there are varieties available that bloom at night. They like it warm and in northern climates, it’s fun to grown one because they are prolific bloomers. It is difficult to winter over these plants but worth the try.
To Pot or not to Pot
Submerged Plants – take them nutrients directly from the water. They are often referred to as oxygenators because they release oxygen into the water during the day. But just like any plant, they consume oxygen at night.
You probably are surprised by the amount of submerged plants. Submerged plants are often the most forgotten plants in the water garden. But they are one of the best plants for helping to balance the ponds ecological system. Fill your container with several bunches of them together and submerge into pond or tie a bunch to a weight and drop into the pond. Use one bunch for every 2 square feet of surface area. Their roots take up nutrients from the water.
These plants absorb nitrogen and provide shade, food, cover, and a spawning medium for the fish.
Oxygenators/Submerged Plants are great at absorbing nutrients from the water that would otherwise feed algae. Koi can be a little hard on them, so for the pond that’s heavily stocked with koi, protection will need to be provided. Koi like to eat them.
Submerged Plant List
Parrot’s feather – will creep along the top of the pond and roots can be tucked into the side of the pond. Can be a little invasive, just keep it under control.
Anacharis – grows on the bottom of the pond. Very good plant and if you can get a good amount growing, it keeps the pond very clean. Sold in bunches.
Hornwort – 12 inches height. Grows from bottom of the pond.
*Not available in Alabama, Arizona, Arkansas, Florida, Louisiana, South Carolina and Texas.
Any unwanted plants should be disposed properly by composing. Never dispose in any natural waterways. They are illegal to use in some states. Please check with your plant supplier before using.
These plants are killed by a hard freeze so in more northern states they are legal to use.
Water Lettuce is another floater but it does not hold up in direct sun as well as Hyacinth.