Top 10 Questions About Water Gardening

By Mary Ellen Ellis | May 12, 2019
Image by ImageegamI
by Mary Ellen Ellis
May 12, 2019

Many people enjoy the serenity that a backyard garden pond provides. And while these garden areas offer peaceful sanctuaries to those that have them, they can also create frustration when gardeners come across issues with which they’re unfamiliar. And that’s where Gardening Know How can help. We get lots of questions about gardening and strive hard to provide answers to the best of our knowledge. Here are some answers to the 10 most commonly asked questions about water gardening.

1. What is the best way to clean pond?

It’s important to clean a garden pond in a way that is safe for plants and fish. The easiest way to keep it clean is to install a filter and pump. You’ll only need to change the filter medium once in a while.  Just be sure there is an intake screen to protect fish. Without a filter system, cleaning the pond by hand once a year should be adequate. Remove debris by hand or with a net. If the water is still pretty dirty, drain the pond and give it a good scrubbing. You’ll have to move any fish and plants briefly to do this. Keep fish in water and plants moist.

2. How to grow water lilies in a container?

First, choose the appropriate plants. Hardy water lilies are best for colder climates and tropical varieties for warmer garden ponds. Prepare plastic pots for water lilies by poking holes in the bottom and sides and filling within a few inches of the top with soil and aquatic fertilizer. Plant the water lily rhizome in the pot with its eye upward and cover it with pea gravel to keep soil in place. Place pots in a pond to a depth of about six to 18 inches (15 to 45 cm.), depending on the variety.

3. How do I care for my garden pond plants over the winter?

Winterizing your pond plants depends on where you live. If you have cold winters, your pond plants will need to come out for the season. Remove them and keep them in a plastic tub or aquarium of water indoors with adequate lighting and warmth. Let the roots stay bare in the water and when the plants begin to sprout again, replant them in pots and set them back in the garden pond.

4. What should I do to winterize my pond?

For colder climates, some winterizing is important for a healthy garden pond. Plants should come out and stay in water indoors for the winter with adequate light and warm temperatures. If you don’t get hard freezes and have hardy pond plants, they can stay in the water for winter. Give the pond a good cleaning by removing debris. Unless it’s really dirty, changing out the water isn’t necessary. For fish, start decreasing their feeding as temperatures get down to 50 degrees Fahrenheit (10 Celsius). If a hard freeze is a risk, use a water pump to keep part of the pond ice-free so fish will survive.

5. Are there any water container shade plants?

Water plants that tolerate some shade include hardy water lilies, arrowhead, bog lily, cardinal flower, parrot’s feather, pennywort, primrose creeper, water clover, and watercress. All plants need some sunlight, so if you have deep shade, keep a shade-tolerant plant in a container and move it to get some occasional light.

6. What plants will survive flooded areas?

Bog plants are great options for areas of gardens that are vulnerable to flooding, as they can grow in wet and dry conditions. Examples include water iris, Siberian iris, cardinal flower, pitcher plant, rose mallow, astilbe, blue vervain, sweet woodruff, daylily, monkey flower, Indian grass, northern sea oats, cattail, elephant’s ear, and water hyssop.

7. What types of plants grow well in ponds?

Plants that grow in ponds are those that thrive in water. Try the classic water lilies, which come in both hardy and tropical varieties. Other popular choices are common waterweed, various types of iris, water hyacinth, marsh marigold, sweet flag, parrot’s feather, water hibiscus, pickerelweed, elephant’s ear, swamp sunflower, and water hyssop.

8. How to install a garden pond?

Installing a garden pond can be a big job. First select a location with four to six hours of sunlight and that will fit the size you want for a pond. Dig out the pond to a depth of about two feet, leaving a shelf of only one-foot depth around the edge for plants. Line the pond with waterproof plastic or pond liner. If using a filter, install it before adding water. Fill the pond with water and check the function of the filter. Let the water sit for about a week before adding plants and fish. Landscape the edges, add in appropriate fish and plants, and enjoy your work.

9. Should you remove cattails and, if so, how?

Cattails in ponds or drainage areas can be a nice landscaping element, but they can also grow out of control. In a drainage area, they may get so thick as to impede water flow, while in a pond they can crowd out other plants. Where they are native, cattails improve the health of these areas. If you do need to thin them, though, you can dig them up by the root. This is physically demanding and may not be possible for a large area. Another option is to drown cattails by cutting them back until they are submerged.

10. Is duckweed invasive in ponds?

Duckweed grows on the surface of ponds and can quickly become invasive and detrimental to the health of the pond. It grows rapidly, covering the surface and blocking necessary light and oxygen, which can result in the deaths of other plants and fish. Prevent duckweed growth by regularly removing organic material, like leaves, from the bottom of the pond. Duckweed thrives in nutrient-rich water. You can also use a net to physically remove duckweed.

We all have questions now and then, whether long-time gardeners or those just starting out. So if you have a gardening question, get a gardening answer. We’re always here to help.

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