[Ebook] Encyclopedia of Aquarium & Pond Fish – Directory of Pond Plants – Marginal plants

Directory of Pond Plants

Marginal plants

These plants are more decorative than functional. However, when planted in containers on the marginal shelf—the ledge around the inside of preformed ponds, about 12 in (30 cm) below the surface—they can provide retreats for young fish. Marginals can also be grown as edging plants, giving the pond a more informal look and creating a barrier that makes it more difficult for predators to reach the fish. Some marginals trail down into the water, which helps to hide the perimeter from view. All the plants featured here are suitable for temperate climates, but some will benefit from protection in winter.

Chinese Rhubarb (Rheum palmatum)

• ORIGINS: Asia, where its distribution is restricted to Tibet and parts of China.
• SIZE: Can grow up to 8 ft (2.5 m) tall.
• WATER: Grows best in moist soil around the perimeter of the pond, rather than in water. Hardy to –20°F (–29°C).
• PROPAGATION: Easily accomplished by division of the rhizome, although it can also be grown from seed.

This spectacular poolside plant grows well in both partial shade and full sun. In spite of its height, it does not suffer badly from wind damage, so it can be useful in exposed positions. The large leaves are supported on strong stems. The most commonly available cultivars have reddish flowers, while the flower spikes of the wild form are white.

Arrowhead (Sagittaria sagittifolia)

• ORIGINS: North America, where it is widely distributed throughout much of the United States.
• SIZE: Attains a height of 3 ft (1 m).
• WATER: Plant in damp soil around the edge of the pond, or on the marginal shelf. Hardy to –10°F (–23°C).
• PROPAGATION: Easily accomplished by the division of established plants.

The green leaves of this hardy marginal are held vertically and shaped like arrowheads. White flowers on spikes are produced throughout the summer. If you wish to restrict the spread of this fast-growing species, plant it in a container from the outset. It forms small tubers that resemble potatoes, and new plants can be grown from these.

Water Forget-Me-Not (Myosotis scorpioides)

• ORIGINS: Europe and Asia, but it has now become naturalized in parts of North America.
• SIZE: Typically reaches 6–12 in (15–30 cm) in height.
• WATER: Fares best in shallow water, rather than being submerged. Hardy to –20°F (–29°C).
• PROPAGATION: Can be grown from seed or by the division of existing plants.

The Water Forget-Me-Not is easy to grow and can help to create a very informal edging around a pond, growing both around the margins and also in shallow water. A number of different cultivars are now established, of which ‘Mermaid’ is probably the most free-flowering, while ‘Semperflorens’ has a more compact growth pattern. The small, pale-blue flowers have tiny yellow eyes at the center, although in ‘Alba’ the blue coloration is replaced by white.

Bowles’ Golden Sedge (Carex elata ‘Aurea’)

• ORIGINS: The native form is widely distributed throughout temperate regions of the world.
• SIZE: Reaches about 24 in (60 cm) in height.
• WATER: Can be grown in shallow water, or alternatively in damp earth. Hardy to –20°F (–29°C).
• PROPAGATION: This can easily be accomplished by the division of existing plants in the spring.

Clumps of this golden-yellow sedge look their best when set alongside contrasting red- or greenleaved marginals. This plant is not particularly invasive, with individual clumps rarely exceeding 18 in (45 cm) in diameter. The brownish flower spikes are hard to see among the arching foliage. At the end of the growing season, cut back old foliage to ensure renewed growth in the spring

Cotton Grass (Eriophorum angustifolium)

• ORIGINS: Widely distributed in temperate regions of the northern hemisphere.
• SIZE: Grows to a height of about 12 in (30 cm).
• WATER: Set on the marginal shelf 2 in (5 cm) below the waterline, or in damp soil. Hardy to –30°F (–34°C).
• PROPAGATION: Usually by the division of the rootstock, although it can also be grown from seed.

This member of the sedge family has distinctive white flowers resembling cotton swabs that stand on tall stems above its grasslike leaves. Despite its rather delicate appearance, Cotton Grass grows and spreads rapidly under favorable conditions. Preferring a position in full sun and acidic, peaty soil, this marginal is often found in moorland areas. Cotton Grass spreads underground by its rootstock, so it is likely to overrun the margins of a pond if it is not properly containerized. Hardy and evergreen, Cotton Grass will blend very effectively into an informal planting plan around the perimeter of a pond, especially when it is interspersed with taller, more statuesque plants. A related species, known scientifically as E. latifolium, is also occasionally available. It has similar growing needs and can be distinguished from E. angustifolium by its wider leaves and the purplish-green coloration of its flowering spikes.

Umbrella Sedge (Cyperus involucratus)

• ORIGINS: In eastern parts of Africa, as well as on the island of Madagascar, off Africa’s southeast coast.
• SIZE: Reaches a height of up to 24 in (60 cm).
• WATER: Typically grows at the perimeter of the pond, or in shallow water. Minimum temperature 40°F (5°C).
• PROPAGATION: By the division of existing plants in fall, although it can also be grown from seed.

Umbrella Sedge is not frost-hardy and requires winter protection in all but the mildest areas. It is best suited to being planted in a container that can be moved indoors before the first autumn frosts. Place the container in a trough of water in well-lit surroundings until late spring, when it will be safe to return the plant to the garden. In milder regions, Umbrella Sedge may survive outside if placed in deeper water than normal, which will prevent the base of the plant from becoming encased in ice. The flowers of Umbrella Sedge form on bracts during late summer. The arching leaves of this plant are an attractive light green when growing but turn brown as fall approaches, with the seed-heads assuming a similar color. For a hardy alternative, Sweet Galingale (C. longus) survives to 0°F (–18°C), but it will still need to be set in a container, because its sharp roots may otherwise damage the pond liner.

African Lily (Zantedeschia aethiopica)

• ORIGINS: This plant is native to southern and eastern parts of Africa.
• SIZE: May reach up to 3 ft (90 cm) in height.
• WATER: Set in containers on the marginal shelf down to 8 in (20 cm), or in damp ground. Hardy to –10°F (–12°C).
• PROPAGATION: This can be carried out by dividing clumps in the spring and also by taking offsets.

This arum lily’s dark green leaves emphasize its large white flowers, with their golden central spadix. The blooms, which may last for a month, are replaced by yellow berries. The plant is most likely to survive outside over winter if it is kept in deep water, which will protect the base from ice. ‘Crowborough’ is the hardiest cultivar available.

Sweet Flag (Acorus calamus)

• ORIGINS: Widely distributed throughout temperate parts of the northern hemisphere.
• SIZE: Can grow to a height of 3 ft (1 m).
• WATER: May be planted in damp ground, or 4 in (10 cm) below the water’s surface. Hardy to –30°F (–34°C).
• PROPAGATION: This can be achieved easily by dividing clumps in the spring.

There are two forms of this rush, both of which have swordlike leaves resembling those of an iris. The wild green form grows more vigorously than the smaller variegated form, whose foliage is striped with creamy white. Sweet Flag grows well both in sunny conditions and in partial shade. Plant it in clumps for maximum impact. The flowers are fairly inconspicuous. Regular divisions of mature plants will encourage good growth.

Bog Arum (Calla palustris)

• ORIGINS: Temperate regions of northern Europe and Asia, and also North America.
• SIZE: Can grow to a height of 8 in (20 cm).
• WATER: Can be grown on the marginal shelf down to a depth of 4 in (10 cm). Hardy to –30°F (–34°C).
• PROPAGATION: Easily accomplished by the division of the rhizomes in the spring.

Although bearing a superficial resemblance to the African Lily (see left), Bog Arum can be identified by its smaller size and the lighter green coloration of its leaves. The white, flattened flowers may be fertilized by water snails rather than by insects. The reddish berries produced after flowering will maintain the plant’s attractive appearance.

White Skunk Cabbage (Lysichiton camtschatcensis)

• ORIGINS: Eastern Asia, on Russia’s Kamchatka Peninsula, the Kuril Islands and Sakhalin, extending to northern Japan.
• SIZE: Can reach a size of 30 in (75 cm) in height and width.
• WATER: Plant in damp soil at the pond’s edge, or in pots 2 in (5 cm) underwater. Fully hardy.
• PROPAGATION: Take offsets from established plants, or grow from seed.

The striking flowers of the White Skunk Cabbage are produced in early spring, thus helping to brighten up the pond at a time when other plants, such as water lilies, are barely stirring into growth. Measuring up to 16 in (40 cm) high, the flowers may sometimes, but not always, have a rather unpleasant odor, as the plant’s name suggests. When White Skunk Cabbage is in bloom, the large, deep green leaves, which are heavily veined like those of a cabbage, will emerge and start to unfurl. This plant fares best when set in relatively rich soil at the side of the pond, although it can also be grown in a container on the marginal shelf. It takes time for White Skunk Cabbage to become fully established, but it grows more rapidly from divisions than from seed. When growing from seed, sow from spring to summer, standing the seed pot in a tub of water to keep the seeds damp at all times.

Japanese Clematis-Flowered Iris (Iris ensata)

• ORIGINS: Asia, where it can still be found growing wild in parts of Japan.
• SIZE: Reaches a height of about 3 ft (1 m).
• WATER: Grows better around the pond’s edges, rather than in the water itself. Hardy to –20°F (–29°C).
• PROPAGATION: Can only be increased reliably by dividing existing clumps.

This particular iris is one of the most beautiful of all poolside flowers, thanks to its large petals, with their relatively broad, flattened shape. It is now available in a wide range of colors, from white to pink and lavender, to shades of purple or blue. Japanese Clematis-Flowered Irises look best when planted together in groups of the same color. For this reason, you should avoid buying a mixed batch of plants and opt only for named color varieties. These irises dislike being permanently waterlogged and certainly should be removed from the pond before winter if they are set in containers. They can then be planted in the ground but must never be allowed to dry out. Choose a sheltered, sunny position where they will not be affected by the wind.

Yellow Flag (Iris pseudacorus)

• ORIGINS: Extends from parts of Europe southward to North Africa, and eastward into Asia.
• SIZE: Grows up to 5 ft (1.5 m) in height.
• WATER: Plant either around the pond or in submerged pots on the marginal shelf. Hardy to –20° F (–29°C).
• PROPAGATION: Most quickly accomplished by dividing rhizomes. Can also be grown from seed.

This hardy iris has green leaves and buttercupyellow flowers with reddish markings at the top of the petals. It blooms fairly early in summer, and although the individual flowers last only for about a day, a number are produced in succession up the flower stem. Yellow Flag grows rapidly, and in ponds it is best to set the rhizomes in marginal pots to restrict its spread and protect the liner.

Flowering Rush (Butomus umbellatus)

• ORIGINS: Naturally found in Europe, Asia, and North Africa, but now also occurs in parts of North America.
• SIZE: Grows up to 5 ft (1.5 m).
• WATER: Will thrive in boggy ground, or in shallow water to a depth of 5 in (12.5 cm). Hardy to –20°F (–29°C).
• PROPAGATION: Achieved by dividing established clumps of the plant.

The dark green leaves of this rush are 1 ⁄2 in (1.25 cm) wide and up to 3 ft (90 cm) long, with sharp edges that apparently deter cattle from eating them in the wild. From midsummer onward, the plant produces spikes of reddish-white flowers, which are displayed as clusters on stems above the leaves. Flowering Rush makes an attractive addition to the border of the pond. While it prefers a sunny spot, it tends not to thrive in very hot climates.

Water Hawthorn (Aponogeton distachyos)

• ORIGINS: Originally from southern Africa, but now occurs in Europe, Australia, and South America.
• SIZE: Leaves may reach 8 in (20 cm) long.
• WATER: Extremely adaptable, thriving in water up to 2 ft (60 cm) deep. Hardy to 20°F (–7°C).
• PROPAGATION: Divide the rhizome. Can also be grown from seeds, which it produces readily

Water Hawthorn will spread across the surface of the pond, readily producing white blooms that have dark centers and a strong smell of vanilla. This marginal grows best in temperate regions, flowering first in the spring and then again in the early fall. Water Hawthorn survives best if set at a depth at which the tubers will not freeze.

Common Cattail (Typha latifolia)

• ORIGINS: Widely distributed throughout much of Europe and North America.
• SIZE: Can reach 6 ft (2 m) in height.
• WATER: Thrives in shallow water, down to a depth of about 12 in (30 cm). Hardy to –40°F (–40°C).
• PROPAGATION: Easily achieved by splitting clumps of established plants.

The cattail’s distinctive female flower is soft, dark brown, and measures up to 9 in (22.5 cm) long. The paler male flower is carried above this on the same sturdy stem. The flowers may be cut and dried for use as winter decorations. The cattail can be invasive unless its spread is curtailed by a suitable container. It grows rapidly and can contribute to the silting up of larger ponds, since mud becomes trapped in its dense root network.

Pickerel Weed (Pontederia cordata)

• ORIGINS: This plant occurs naturally in eastern parts of North America.
• SIZE: May grow to 3 ft (1 m) tall.
• WATER: Grows well on the marginal shelf, to a depth of 5 in (12.5 cm). Hardy to –40°F (–40°C).
• PROPAGATION: Can be rooted easily by breaking off pieces from existing rootstock.

This plant has broad, tapering green leaves and upright flowers. Although Pickerel Weed tends to be quite slow growing in spring, it has a long flowering period that lasts well into late summer, when other plants are finished blooming. Pickerel Weed prefers a position in full sun, either planted in a damp spot, such as a bog garden adjacent to a pond, or permanently submerged in the pond itself. In addition to P. cordata, some other forms of Pickerel Weed are available. Those found in more southerly parts of the US—such as the WhiteFlowered Pickerel Weed (P. alba), which is naturally restricted to northern Florida—are unlikely to be as hardy as P. cordata. The roots of these marginals should not be allowed to become frozen in ice if they are to continue growing again the following year. Pickerel Weed can spread rapidly, and since it looks best in clumps, set the roots in relatively large planting baskets at the outset.

Monkey Flower (Erythranthe guttatus)

• ORIGINS: Occurs naturally in western parts of Canada and the US.
• SIZE: Can reach up to 3 ft (1 m) in height.
• WATER: Grows underwater in the winter, and then puts up sprouts during the spring. Hardy to –10°F (–23°C).
• PROPAGATION: Can be grown quite easily from seed, as well as from cuttings.

This is one of the hardiest of the Erythranthe species, which grow wild in the Americas as far south as Chile. Wide hybridization of the Monkey Flower has produced many different varieties. Appreciated for its vivid flowers, it is usually cultivated as an annual, even though some varieties can overwinter. Monkey Flower seeds should be sown in the spring

Water Canna (Thalia dealbata)

• ORIGINS: Occurs in southern parts of the US and across the border into Mexico.
• SIZE: Can reach up to 6 ft (2 m) in height.
• WATER: Needs to be planted quite deep in the pond, down as far as 18 in (45 cm). Hardy to 0°F (–18°C).
• PROPAGATION: This is easily achieved by the division of the rootstock.

Hardier than its distribution might suggest, this Water Canna’s angular leaves unfold off a central stem, which in late summer may be crowned with a purple flower spike. This plant does well in the deeper areas of a pond, especially in temperate zones, since this provides the rootstock with a barrier against ice. For added protection in winter, the stems can be wrapped in burlap

Creeping Jenny (Lysimachia nummularia)

• ORIGINS: Natural distribution in the wild is restricted to parts of central Europe.
• SIZE: Can grow to a height of 6 in (15 cm).
• WATER: Grows best around the edges of ponds, rather than in the water itself. Hardy to –30°F (–34°C).
• PROPAGATION: Divide established plants or take cuttings. Can also be grown from seed.

This low-growing member of the primula family spreads by shoots, which can reach more than 12 in (30 cm) in length. With yellow, cup-shaped flowers and green leaves, Creeping Jenny provides excellent groundcover around the pond edge, even in shady areas. However, it grows vigorously and may even invade the lawn. The variety L.n. ‘Aurea’ is often a better choice, being less invasive and also more attractive, thanks to its golden leaves.

Water Avens (Geum rivale)

• ORIGINS: Found in temperate regions of Europe, Asia, and North America.
• SIZE: Can grow to a height of 12 in (30 cm).
• WATER: Grow in shallow water, or in damp soil around the edges of the pond. Hardy to –40°F (–40°C).
• PROPAGATION: Take cuttings, which will root easily. Can also be grown from seed.

Water Avens is a good choice for the surroundings of a pond, where low groundcover is needed. Its green leaves are reminiscent of those of strawberries. A number of different cultivars are now established so that plants with flowers of varying colors are available, ranging from the natural purplish-pink to shades of orange and yellow. Water Avens is a hardy perennial that will regrow well in spring after being cut back in fall.

Gunnera (Gunnera manicata)

• ORIGINS: South America, where it grows along waterways in Colombia and Brazil.
• SIZE: Stems can grow up to 6 ft (2 m) tall.
• WATER: Grow beside the pond, rather than in the water itself. Hardy to –0°F (–18°C).
• PROPAGATION: Can be carried out by the division of existing plants. May also be grown from seed.

With leaves up to 6 ft (2 m) wide and greenish flower spikes standing 3 ft (1 m) tall, this marginal needs very spacious surroundings. Gunnera, also known as Giant Rhubarb, grows rapidly in a sunny yet sheltered location with rich, damp soil. When it dies back in winter, use the leaves to mulch the crown, which will help to prevent frost damage.

Giant Water Buttercup (Ranunculus lingua ‘Grandiflorus’)

• ORIGINS: Found in temperate regions of Europe, Asia, and North America.
• SIZE: Can grow up to 30 in (75 cm) tall.
• WATER: Plant in the pond itself, down to 5 in (12.5 cm), or in marshy surroundings. Hardy to –20°F (–29°C).
• PROPAGATION: Easily propagated by the division of its tuberous rootstock. Can also be grown from seed.

This is the most spectacular of all the buttercups, thanks to its large size and the vivid yellow flowers it produces in spring. Like other members of its family, the Giant Water Buttercup can become rampant if its growth is unchecked, so it should be set in marginal containers from the outset. The leaf shape is variable, being broader and longer on stems that do not form flowering shoots.

Marsh Marigold (Caltha palustris)

• ORIGINS: Widely distributed throughout much of North America, Europe, and Asia.
• SIZE: Can grow 12 in (30 cm) or more in height.
• WATER: Plant in damp ground around the edge of the pond, or in shallow water. Hardy to –40°F (–40°C).
• PROPAGATION: This can be achieved by the division of existing plants, or by growing from seed.

Flowering both readily and early in the year, Marsh Marigolds look best when planted in small groups. Several cultivars now exist, including the doublebloomed ‘Flore Plena,’ which may flower again in early autumn, and a less vigorous Himalayan white form, C. p. var. alba. The leaves of Marsh Marigolds may suffer from mildew later in the year.

Hart’s-Tongue Fern (Asplenium scolopendrium)

• ORIGINS: This species occurs naturally in temperate parts of Europe.
• SIZE: Individual fronds can be up to 16 in (40 cm) long.
• WATER: Grow in moist soil around the water’s edge. Never submerge this plant. Hardy to –10°F (–23°C).
• PROPAGATION: Divide plants or take leaf cuttings. Propagates naturally through the dispersion of spores.

The attractive shape of ferns makes them a popular choice for the surroundings of a pond, and numerous species grow well in such locations. Hart’s-Tongue Fern is one of the hardy ferns, ideal for temperate areas. It has an upright growth habit, especially in the case of new fronds, which are pale green but become darker as they mature. The leaves are wavy and up to 2 in (5 cm) wide. Although ferns will not thrive if kept saturated, they do require a relatively high level of humidity. Plant them in a shady spot where they can draw moisture, such as in a crack in the rockwork around the pond, or even adjacent to a waterfall, where they will benefit from the water spray even in dry weather. Kept in favorable surroundings, they will soon start to reproduce. Small offspring may develop in tiny crevices and grow successfully if they are not allowed to dry out. Ferns generally prefer a shady location, out of direct sunlight.

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