Right Plant, Right Pond, Nothing Left Out!

A water garden is not a water garden
without plants. A pond is not a
complete ecosystem without
plants, either. Plants are a key element
and play an essential role in maintaining
good water quality and a healthy,
balanced habitat. Choosing the right
plant palette for a water garden or pond
depends on the goals and primary use of
the water body. Careful consideration of
these goals should be exercised during
plant selection so as to avoid any issues
that may arise from an overly aggressive
plant — issues that may result in the
need for physical removal or, in some
cases, the use of an aquatic-approved
herbicide. A good planting plan takes
into consideration the primary uses of
a pond and balances it with the need for
aquatic vegetation to achieve a functioning,
healthy ecosystem.

Once the objectives and goals have
been identified, the first step toward
formulating a good planting plan is
to observe the site. Inventory existing
vegetation; note non-native plants and
invasives that need to be addressed as
well as desirable native plant populations
that can be enhanced. Note the inlet
and water source, as well as the outlet
structure. Consider the entire watershed
of the pond. Special attention should
be paid to the primary and secondary
sources of water. It is in these areas that
plants can be used to slow water down
through vegetated swales, trap sediments
and aid in nutrient removal before
the water reaches the main water body.
Look close to notice seasonal high and
low water levels based on existing plant
growth. Observe the wind patterns of
the site, especially on larger ponds and
lakes. This will help to identify areas of
organic deposition and wave action that
may result in erosion issues if the area is
not planted. Wind can also be used as
a means of seed dispersal as plantings
become mature.

Plant Selection

The rate of spread is an important characteristic to be familiar with when considering certain species. Speaking simply, aquatic plants can be broken down into two types regarding their rate of spread. The first is “clump-forming,” and the other is “colony-forming.” Clump-forming plants do as they sound. They will, upon maturity, form large, stationary clumps without running around via roots. Like all plants, however, they will produce and disperse seed —some more aggressively than others. Colony-formers can be broken down further into two subgroups:

1) Stoloniferous plants — Stoloniferous plants spread by aboveground stems laying horizontal sending roots and new shoots at each internodal section.

2) Rhizomatous plants — Rhizomatous plants spread via modified underground roots called rhizomes that produce roots and shoots to form new plants.

Some colonizers can quickly get out of hand by also producing hundreds of seeds along with their stoloniferous or rhizomatous nature. A good example would be Cattails, or Typha spp.

In general, rhizomatous plants are the workhorses of the aquatic plant world; they cover a lot of ground in a few seasons, form dense mats of growth and help stabilize large areas of shoreline. Aesthetically, large sweeps of texture or blooms can be pleasing to the eye, and functionally, colonies of well-rooted emergent vegetation will provide habitat and cover and will also help to break up wave action and stabilize the pond bank. Clump-forming plants add diversity to large plantings and can be used to fill in gaps between colonies. In
smaller ponds, “clumpers” can also be planted en masse to achieve the same results as a large colonizer but maintain a certain controlled planting.

Native Rhizomatous/Stoloniferous Plants for Large Ponds

• Acorus americana
• Carex lacustris
• Decodon verticillata
• Dulichium arundinaceum
• Eleocharis palustris
• Menyanthes trifoliate
• Polygonum amphibium
• Pontederia cordata
• Sagittaria latifolia
• Saururus cernuus
• Scirpus tabermontanii
• Sparganium eurycarpum
• Sparganium americanum

Native Rhizomatous/ Stoloniferous Plants for Small Ponds

• Acorus americana
• Dulichium arundinaceum
• Justicia americana
• Menyanthes trifoliate
• Sparganium americanum

Excellent Native Clump-Forming Plants for Every Pond

• Carex stricta
• Hibiscus moscheutos
• Iris fulva
• Iris versicolor
• Juncus effusus
• Orontium aquaticum
• Peltandra virginica

Go Native

As a general rule of thumb when considering plants for an earthbottom pond, nursery-produced local native plants should be used. Therefore, if any seeds escape in a storm event, they will only contribute in a positive manner downstream. These plants will also be better-adapted regionally, help maintain diversity of the local gene pool and provide food and cover to the bird and insect population in the area.

At home in the small water garden, cultivars of native plants can be used in conjunction with the straight species to add a little ornamental flair.

Some great selections of native aquatic cultivars include:

• Dulichium arundinaceum

  

• “Tigress”
• Hydrocotyle rannunculoidies
• “Crystal Ball”
• Orontium aquaticum “Big Red”
• Sagittaria australis “Bennii”

Getting to know native aquatic plants and their hydrological zonation is key to making the right choice for any pond, but always choose the plants after the primary objective and goals have been set and a complete site analysis has been performed.