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Arbordale Blog

An ongoing series of informational entries

Pond plants

aquatic plants department

Adding plants to the pond

March 15, 2022

Plants should be an integral part of any backyard pond, but how can you add plants to your pond for the best natural balance and easiest care?

Why Plants Are Essential

Plants are critical to a healthy pond ecosystem in many ways, and understanding what plants bring to your pond can help you add just the right vegetation to reap the biggest benefits. In your pond, different plants will…

Limit Algae Growth

Because pond plants block sunlight from the depths of the water, they help minimize unsightly algae growth that can clog filters and turn water murky. Plants also use plenty of the nutrients in the water, which will also keep algae from thriving.

Shelter Fish

If fish, frogs and other aquatic wildlife have a home in your pond, the right plants can provide safe shelter to protect them from potential predators. Many fish and other wildlife will also nibble on plants as a natural food source.

Oxygenate the Water

Plants help raise the oxygen level of your pond's water, making it healthier for fish and reducing the need for artificial bubblers or oxygenators. When fish lack proper oxygen, they are more susceptible to diseases and poor health. Algae also thrives in low-oxygen water.

Filter the Water

Because plants absorb nutrients from the water, they are part of a natural filtration system that can keep your pond looking pristine. While overcrowded or sickly plants can die off and create murky water and excess debris, properly balanced plants are excellent natural filters.

Naturalize the Setting

Plants help soften the barriers between your pond and the rest of your yard, creating a more organic, natural look to the landscape rather than stiff, artificial borders. Use plants to mask pond equipment, drains, piping or other artificial structures such as fences or posts.

Improve Beauty

Plants can be a lovely feature of any pond. Unique foliage shapes and colors, aquatic blooms and interesting growth habits all add visual interest to your pond, creating a stunning waterscape you can enjoy for years.

Choosing the Best Plants for Your Pond

Not all plants will be right for every water feature, and there are certain factors you must consider when choosing which plants to add to your pond. Poorly chosen plants may die quickly or could take over your watery landscape, crowding out other plants and clogging the pond. Some plants may not adapt to your climate, while others may not be the best size or shape for your pond style. When choosing plants, carefully consider…

Light Levels: How much light do pond plants need for healthy growth? Is your pond shaded by other plants, trees or structures?

Mature Size: How large will your plants grow compared to the total size of the pond? Will they outgrow a small pond or get lost in a larger pond?

Hardiness: Will your plants survive cooler waters in the pond during fall and winter? What care will they need if the pond freezes? Can they tolerate sudden temperature changes?

Variety: Are you choosing plants that will look good together? Do you have plants of different heights, shapes and colors for more interest?

Fish Food: Are you choosing plants fish will eat quickly, just nibble on or leave alone? Will the interest of aquatic wildlife destroy your carefully chosen plants?

Ideally, you will want to cover approximately 60 percent of the pond's surface with plants. This provides the best balance of water protection and healthy space for the plants.

Plants to Consider

There are three different types of plants to choose from when adding vegetation to your pond.

Floating Plants: These plants have foliage and blooms above the water's surface, while their roots trail below. They work well in moderate water depths or deeper water. Water hyacinth, water lettuce, frogbit, parrot's feather and sensitive plant are all top floating plants for ponds.

Bog Plants: These plants thrive in shallower water along the edges of ponds, and their foliage extends above the water's surface. Irises, cattails, pennywort, rushes and water hawthorne are all good options for bog or edging plants.

Submerged Plants: These plants are almost entirely below the water's surface and are excellent filters in ponds of all sizes. To stay fully submerged, they require deeper water. Hornwort, vallisneria, water moss, curled pondweed and red ludwigia are all popular submerged plants.

Choosing plants from each general type will help you find the best vegetation for your pond and create a thriving aquatic ecosystem. Once you have chosen the specific plants you prefer, follow instructions for adding them to your pond carefully and monitor them closely until they become established. Soon, you will have a healthy, attractive pond filled with stunning plants to enjoy.


Our hydrangea does not bloom - help!

February 14, 2022

Hydrangeas add beauty to any landscape. They have attractive foliage and produce large, striking blossoms. Hydrangeas are also hardy, insect, and disease resistant, and versatile. They grow well in a variety of soils and tolerate wetness better than most other woody plants. One drawback is that different cultivars require different pruning styles and many gardeners don’t know how and when to prune them.

Hydrangeas that bloom on old wood from last year’s growth are the earliest to flower – before July. Those that bloom later in the season – after July – are flowering from blossom buds on new wood that is growing during the current year.

If you feel uncertain about which variety you have, a safe rule for all types of hydrangeas is that no pruning is better than the wrong type of pruning.

A simplified approach, suitable for all types of hydrangeas, is to limit pruning to:

Winter-killed wood — Remove all dead branches in the spring before or as the buds are opening. Test the stem for life by scraping the bark with a knife. If it’s not green underneath, it’s dead and should be removed.

Rejuvenation — Old wood dies back on even the healthiest hydrangeas. In the early spring remove dead or very old stems by cutting them at the base of the plant. This will stimulate new growth and produce a more vigorous bloom set later in the summer.

Dead flowers —Removal of old dried flowers, known as dead-heading, is the safest pruning and can’t be done incorrectly.

Bigleaf hydrangea (Hydrangea macrophylla)

This is the most commonly grown hydrangea in NY. It has attractive, lustrous leaves and large blue, pink, red, or purple flowers. These hydrangeas include two forms: the mophead and the lacecap types. Both are pruned the same way. This group of hydrangeas also includes the repeat bloomers, which bloom on both the old wood from the previous year and on the current season’s wood. A popular cultivar of the repeat bloomers is ‘Endless Summer' but there are many newer repeat blooming cultivars available in the trade.

Sometimes bigleaf hydrangeas become overgrown and need to be trimmed. However, too much pruning will greatly reduce or eliminate flowering. In late summer, after the bloom period, dried flowers can be removed. But, it’s best to wait until new growth emerges in the early spring to be sure that you are only removing dead or weakened parts and not removing live stems with flower buds. In very old and declining hydrangeas, hard renewal pruning may be needed. Cut back all of the branches to the ground. This will eliminate the blossoms for that year but the next year should be quite productive.

The flower color of the macrophylla species is dependent on soil pH. A pH below 6.5 will produce blue flowers and a higher pH will produce pink or red flowers.

Smooth hydrangea (Hydrangea arborescens)

Native to the North American woodlands, it is fairly common in home landscapes. This species blooms with white flowers on new wood of the current season, making it the easiest to prune. Simply cut it back hard in early spring. Flowering is actually enhanced by cutting back all stems to about 12 inches from the soil line. Well-known cultivars include ‘Annabelle’ and ‘Grandiflora'.

Pee Gee hydrangea (Hydrangea paniculata)

Originally from the Orient, this is one of the largest hydrangeas. It can reach 25 feet high. It has brittle stems that may break under a load of white blossoms in windy weather or under heavy snow. Remove broken stems as they occur to keep the plant healthy. Like the smooth hydrangea, it also flowers on the current season’s wood. Pruning in the spring will actually enhance flowering as well as help to manage its size. If the size is of no concern, simply remove spent flowers and any broken stems. Cultivars of merit include ‘‘Limelight.’

Oakleaf hydrangea (Hydrangea quercifolia)

The oakleaf hydrangea is a beautiful native of the southeastern United States and is a favorite of many gardeners. Its foliage is spectacular even without the massive, upright, 12-inch blossoms. Its flowers are produced on old wood from last year’s growth. In NY it blooms in late June, but the flowers persist through the summer and gradually change from white to pink, and eventually to a tan color in the winter. If needed, prune after flowering to maintain a desired size and shape. Winter-killed or other deadwood can be removed at any time.

Climbing hydrangea (Hydrangea anomala subsp. petiolaris)

This trailing-vine species is a vigorous grower that is attractive and easy to maintain. The only pruning needed is to remove unwanted stray stems to control their growth. This may need to be repeated several times in the season as the vine quickly produces new stems. In NY, it flowers in May and June on old wood from the previous year. To avoid reducing bloom, prune them after blooming.

Author: Raymond Bosmans, Professor Emeritus, University of Maryland

Editor: Jeanine Smetana, University of Maryland Extension Master Gardener

Adapted from an article in the May-June 2010 HGIC E-Newsletter


How to choose size of pondless waterfall basin

January 15, 2022

Use the formula :

Length of waterfall x width of waterfall x (0.25 x Depth of water) = how many cubic feet of water you need running down your waterfall, also called water in motion.

Of course, we don't normally measure water in cubic feet. There are 7.48 gallons per cubic ft of water. Muliply how many cubic feet of water from the formula above x 7.48, and you will have how many gallons of water you need.

To find out how much water you need for the entire system, multiply the amount of water in motion you need x 2.5. This will give you enough water to keep the pump submerged at all times, and not have an overflow when the pump is turned off. 

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