Submerged Aquatic and Bog Plants

Submerged Aquatic Plants

The chief reasons for using submerged aquatics are to maintain water clarity (they compete with algae for food and light), to provide nurseries where fish can lay their eggs, to hide and protect the young fry after hatching from the cannibalistic tendencies of their parents, and to provide food for all kinds of live-stock.

Unlike plants in aquaria, these plants are rarely seen in a pool, so that daintiness, leaf texture and colouring matter little. The most important thing is their oxygenating abilities; some have been proved better than others in this respect. A few come to the surface and produce flowers that stand above the water to be insect pollinated, but the majority have insignificant blooms fertilized by sperm brought by water currents. One or two are deplorably weedy and will choke water-lilies and other plants if given undisputed sway.

The following species are recommended and should be planted liberally.

A 4 by 6-ft. pool will require some two dozen oxygenators; pools of other sizes should be stocked proportionally.


Anacharis canadensis (syn. Elodea canadensis) (American pond weed), dark green, small leaves, and brittle stems. A very good oxygenator.


Hottonia palustris (water violet), 1 to 2 ft. Cut foliage and spikes of mauve flowers above the water in June and July.


Lagarosiphon major (syn. Elodea crispa), resembles a large curly-leaved anacharis; another good oxygenator.


All members of this family have attractive leathery leaves and are useful as oxygenators.


Most potamogetons are useful in a pool and are entirely submerged, but beware ol the floating species, Potamogeion nutans.


Ranunculus aquatilis (water crowfoot), small white, floating flowers in spring. Does well in still or running water.

Bog Plants

These are decorative plants for the pool-side, which like moist soil but not standing water, and look most effective if they are grouped in bold clumps. The majority are propagated by division in spring.


These are handsome perennials with spikes of mostly blue, helmet-shaped flowers and deeply cut, smooth leaves like those of the buttercup. Suitable for sun but will last longer in the shade. Good kinds which grow from 2 to 4 ft., and flower from June to August are:

Aconitum carmichaelii (syn.A.fischeri), deep purple.

A.c. Wilsonii, a vigorous form, blue or violet flowers with very large helmets.

A. napellus, blue.

A.n. Album, white.

A.n. Bicolor, blue and white.

A.n. Newry Blue, very deep blue.


Good ground-cover plants for sun or partial shade. Small green leaves on creeping stems and spikes of blue flowers.

Ajuga reptans, 6 to 12 in., a British plant, flowers from June to July. Its varieties with variegated or coloured foliage, such as atropurpurea. Rainbow and variegata are more garden-worthy.


Anagallis tenella (bog pimpernel), 2 to 4 in. Rosy-pink, bell-shaped flowers in summer and small opposite leaves, a charming native annual for a wet place.


Aruncus Sylvester (syn. Spiraea aruncus), 4 ft., a noble plant with deeply cut, spiraea-like leaves and impressive plumes of creamy-white flowers in June. Will remain for years in the same situation.

A.s. Kneijfii, has more finely cut foliage.


The hardy bamboos make good wind-breaks and shelters and look very effective in such settings. They need a good loamy, moist soil, and may take several years to become established, but after-wards are no trouble. Bamboos are evergreen and rarely, if ever, flower. Prospective buyers are advised to visit a specialist grower and select after examination. The following are hardy bamboos and vary in height from 1 ft. to as much as 20 ft.: Arundinaria, Phyllostachys. Pleiobastus, Pseudosasa and Sasa.


Asclepias incarnate, 3 to 3-½ ft. Stout, grey-green, leafy stems, and showy umbels of flesh-pink flowers in July and August.


These are important perennials for pool-side planting, associating well with irises, primulas and day lilies. They are very adaptable provided the soil never dries-out, but plenty of sun is essential for flowers. In light soil, peat or leaf mould mulches should be given annually about April. The roots of astilbes always remain close to the surface so that mulches-retain moisture as well as feed the plants.

The leaves are compound and the flowers are borne in feathery plumes from July to August. Most of the garden forms are of hybrid origin. Excellent kinds that grow from 2 to 3 ft. high are:

Apple Blossom, soft pink.

Avalanche, white.

Betsy Cuperus, pale pink.

Burgkristal, white flowers like coconut-ice.

Etna, deep red.

Granat, crimson.

Salland, deep rose.

William Reeves, dark crimson with bronze foliage.


Astrantia carniolica. 1 ft., a curious little plant with buttercup-like leaves, and round heads of white or blush-pink flowers enclosed in a ring of green and white bracts in July and August.

A.c. Rubra, similar but with redder flowers.


Brunnera macrophylla (syn. Anchusa myo-sotidiflora), 1 to 1-½ ft. Rough, heart-shaped, basal leaves, and spikes of bright blue forget-me-not flowers in April; a charming little perennial for damp soil and partial shade. Propagated by root cuttings or division.


Buphthalmum speciosum (syn. Telekia speciosa), 3 to 4 ft., robust perennial with large yellow daisies from July to September, and large heart-shaped leaves. A plant to group by itself or with other vigorous species, as it could smother small plants.


Camassias are bulbous plants with broad, strap-shaped leaves and spikes of blue, white or soft yellow flowers, and are very showy, especially when grown in grass. They will tolerate very wet conditions. The following flower in May and June: Camassia esculenta, 1 to 1-½ ft., light blue.

C. leichtlinii, 3 ft., creamy-white.

CI. plena, 2 ft., sulphur-yellow double flowers.

C. quamash, 2 ft., dark blue.

Cardamine pratensis, cuckooflower.

Cardamine pratensis, cuckooflower. (Photo credit: Wikipedia)


Cardamines are spring-blooming perennials which associate well with calthas and primulas.

Cardamine pratensis, the common cuckoo flower, 1 ft., flowers pale purple to white from April to May.

C. pratensis Flore pleno, pale lilac, double blooms which are borne on showy spikes.


Bugbanes are suitable for the drier parts of the bog garden and useful for their late flowers, which are whitish and appear from July to September; the flowers are attractive en masse and are borne in erect spikes on branching stems 3 to 7 ft. high, the leaves being heart-shaped and cut into lobes.

Cimicifuga Americana, C. Dahurica, C. racemosa are all very similar.

C. simplex, has the most showy flowers.


These are coarse perennials for growing amongst vigorous plants. The following kinds flower in August and September: Eupatorium ageratoides, thin, long-stalked, opposite and oval leaves on 2- to 4-ft. stems carrying large flat heads of thistle-like flowers.

E. cannabinum, 3 to 4 ft. Purple flowers, less attractive than its double form.

E. c. plenum is very spectacular.


A beautiful genus formerly associated with the spiraeas, having pinnate or palmate foliage and feathery sprays of fluffy flower heads. Likes sun or partial shade, but a perennially moist soil is essential. Propagated by division or seed sown soon after harvesting.

Filipendula camtschatica (syn. Spiraea gigantea), 4 to 8 ft., has large heads of fragrant white flowers in May.

F.c carnea, pink flowers.

F.c. Rosea, rose flowers.

F. hexapetala, 2 to 2-½ ft. Creamy-white flowers in June and July. There is a double form flore pleno.

F. rubra, 2 to 5 ft., rosy flowers in June.

F.r. Venusta, deep pink flowers.

F. ulmaria (common meadowsweet), 2 to 3 ft. Creamy panicles of blossom from June to August and three to five-lobed leaves; is well known and worth a place in the water garden. It has given rise to several forms including:

F.u. aurea, golden leaves.

F.u. flore pleno, the double form.


These little bulbous plants readily colonize in moist ground and flower in April and May on 1 ft. stems.

Frilillaria meleagris, curious, hanging flowers patterned in purple and white squares like a chess board. Plain white and reddish-purple forms frequently appear in naturalized colonies.


An imposing plant, from 8 to 10 ft., for the large water garden. It has enormous rhubarb-like leaves, sometimes 10 ft. by 7 ft. across, on thick spiny stems. The flowers are clustered on spikes that may be as much as 3 ft. long and resemble a giant bottle-brush.

When frost in autumn blackens all the growth above ground, the leaves should be removed and inverted over the crowns to form a natural protection and mulch.

Gunnera manicata, is the kind most usually grown but G. chitensis (syn. C. scabra) has more reddish flowers and stems. Flowers from June to August.


Day-lilies are invaluable for associating with irises and primulas, and have arching, grassy foliage and spikes of amaryllis-like flowers from June to September. These last only a day, but so many buds are produced that the flowering season is usually extended over six to eight weeks. Suitable for damp or even wet spots, in sun or shade. There are many garden varieties, of which the following are representative:

George Yeld, 2 ft., rich orange.

Hesperus, 4 ft., soft citron-yellow.

Hyperion, 2-½ ft., golden-yellow.

Pink Lady, 3 ft., pink.

Royal Ruby, 3 ft., red-crimson.

The Doctor, 2-½ ft., deep red.


Hostas, which are often referred to by their old name of funkia, are fine, foliaged plants which like moist soil and somewhat shaded situations. The flowers are white or mauve, funnel-shaped and borne on slender spikes. The following grow from 1 to 2 ft., and flower at various times during the summer:

Hosta decorata, oval leaves margined with white, and dark blue flowers.

H. glauca, corrugated, bluish-green foliage and pale lilac blooms.

H. lancifolia, very narrow green leaves and lilac flowers.

H. plantaginea, white blooms and oval, heart-shaped leaves.

H. undulata, green leaves heavily splashed with white, and pale lilac flowers.


Showy perennials with large, daisy flowers, 2 to 4 in. across, and rough leaves. They require plenty of sunshine.

Inula helenium, 3 to 4 ft., has bright yellow, ragged-petalled sunflowers about 3 in. across in summer.

I. royleana, 2 ft., has black buds, surmounted by a green collar or sepals, which open to large orange flowers. Blooms from August to October.


An important family in the water garden and one that should receive full representation. No lime should be given to any of the following species and varieties:

Iris delavayi, often reaches 4 ft. in moist soil, a deep purple iris of the siberica type. Flowers in June.

I. forrestii, 1-½ ft. Good clear yellow flowers in June and grassy leaves.

I. kaempferi.

I. siberica, 2 to 3 ft., grassy leaves and dainty, poised flowers in June; is well known as a border perennial but gives bigger blooms in wet soil.

Varieties include:

Caesar, deep purple.

Perry’s Blue, light blue.

Snow Queen, white.

Tropic Night, almost black.


Although not reliably hardy, the bog lobelias are well worth a little cultural trouble. The scarlet-flowered forms of Lobelia fulgens are particularly bright and doubly colourful as they also have crimson leaves. Stock can be preserved from year to year by lifting the roots towards the end of September and packing them round with soil and leaves in a cold frame. Alternatively, August-rooted cuttings can be kept under glass for the winter months. During this winter resting period they should be kept rather dry. Plant out again in mid-May. Propagate by seed raised in gentle heat in February, by cuttings, or by spring division.

Varieties of Lobellia fulgens that reach from 1 to 3 ft. and flower from May until September include:

Huntsman, bright scarlet.

Purple Emperor, purple.

Queen Victoria, deep purple leaves and spikes of crimson flowers.

L. syphilitica, 1 to 3 ft. Hardy with spikes of light blue, tubular flowers from July to October, and narrow, oblong leaves.

L.s. slba, similar but with white flowers.


Lysichitum americanum, 2 to 3 ft., a large aroid with showy, deep yellow arum flowers 1 to 1-1/2 ft. in height, which bloom in May and are succeeded by large, glaucous leaves. Not suitable for a small garden. Propagate by seed or division.


Easily-grown plants for wet soil and sun or partial shade. The following reach from 2 to 3 ft., and flower from June until August: Lysimachia clethroides, spikes of pure white, primrose-like flowers.

L. thyrsiflora, yellow, will even grow right in the water.

L. vulgaris, a showy native which has leafy spikes of yellow flowers.


The genus includes some of our brightest and gayest summer perennials, with densely packed spikes of sage-like flowers, mostly red and purple. The following grow from 2 to 4 ft. and flower from June to September.

Lythrum salicaria, red-purple flowers, is less garden-worthy than any of the following:

Lady Sackville, vivid rose-purple.

Morden’s Pink, deep pink.

Rose Queen, bright rose.

The Beacon, rosy-red.


Musks are low-growing plants of doubtful hardiness in some areas, but invaluable for the brightness of their flowers in late summer. They grow readily from seed, or named varieties from cuttings wintered under glass. The most useful are hybrids from Mimulus guttatus such as Bees Dazzler, with pillar-box-red (lowers; also mixed hybrids cupreus, maculosus and tigrinus, and the hose-in-hose sorts which have a double corolla ring. All these grow from 8 to 12 in. and flower from June until September.


All the following grow from 2 to 2-½ ft. and flower from June to September.

Monarda didyma, has square stems, bright red, nettle-like flowers and fragrant leaves.

M.d. Beauty of Cobham, clover pink.

M.d. Crimson King, crimson.

M.d. Croftway Pink, rose-pink.


This is a large family, the majority favouring a moist soil that never becomes dry or waterlogged. An occasional top dressing of well-rotted manure and leaf mould is beneficial but not essential. Allow the seed to drop round the parent plants and form colonies — many sorts will inter-hybridize under such conditions. Propagation by seed sown directly after gathering, or by spring division.

The candelabra primulas carry flowers of various shades in a succession of whorls up the stems and are the most ornamental in the water garden. They include the following, which grow from 2 to 3 ft. and flower in June:

Primula beesiana. Rosy-carmine flowers.

P. japonica, white, pink and crimson flowers.

P. helodoxa, golden flowers.

P. pulverulenta Bartley Strain, with mealy stems, has produced many fine shades in pink and rose.

Other good species are:

P. rosea, 6 in., which will tolerate standing moisture for short periods and has rich pink flowers in April.

P. sikkimensis, 2 ft., like a giant cowslip, carrying many nodding, fragrant, pale yellow flowers in July.


These are fine foliage plants with handsome leaves and spikes of astilbe-like flowers. Increase by root cuttings or division.

Rodgersia aesculifolia, 3 ft. Bronze leaves shaped like those of the horse-chestnut, and flat sprays of fluffy, white flowers in June and July.

R. podophylla, 4 ft. Heavily netted bronzed leaves divided into five deeply toothed lobes, and yellowish-white flowers from June to July.

R. rabularis, 3 ft. Leaves almost round, 2 to 3 ft. across on thick, bristly stems, and white flowers in July and August.


Ragworts are showy plants of vigorous growth with daisy flowers and coarse, toothed leaves. Suitable for the larger garden.

Senecio clivorum (syn. Ligularia clivorwri), 3 to 4 ft. Large, round, toothed leaves, 1 ft. or more across, and much branched heads of large (2 to 3 in.) orange-yellow flowers in July and August.

Othello, an improved form.

S. pulcher, 1 to 2 ft. Rosy-purple flowers, 2 to 3 in. across, from August to October, and long, lobed, silver leaves. Needs winter protection in exposed positions.

S. tanguticus, 3 to 4 ft. A handsome plant with upright stems, deeply cut leaves and panicles of golden-yellow flowers in September.


Globe flowers are handsome relations of the buttercup with cut leaves and ball-like heads of yellow or orange flowers. Suitable for sunny places in wet soil. Varieties are preferable to species, especially the following, which grow from l to 2 ft. and flowering May and June: Bees Orange, orange-gold.

Earliest of All, butter-yellow.

Lemon Queen, very pale yellow.

Salamander, fiery orange.


01. June 2012 by Dave Pinkney
Categories: Aquatic Plants, Water Garden Plants | Tags: , , | Comments Off on Submerged Aquatic and Bog Plants


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