Floaters: Pond Plant Group
Floaters-
Other Names ( none )
Roots submerged, leaves and stems free-floating on or just below the surface
and flowers, if any, on or above the surface.
Their
main purpose is to provide surface cover where Water Lilies or Deep-water
aquatics are sparse or absent, but a few are also ornamental. There are two
basic types- the carpeter such as Lemna and Azolla which can cover the whole
surface with tiny leaves and the non-carpeters which have larger leaves and
tend to be less invasive. Planting could not be simpler. Floaters are available
between April and September, and you just drop the plants in the water. In
a large pond, use with care as control can be difficult. In winter most hardy
Floaters sink to the bottom of the pond and survive as buds or
seeds.
Azolla-
Fairy Moses
This
is the mostly widely available of all the floaters, and the one you will
almost certainly be offered is the
Azolla
Carloliniana.
It is a tiny fern with fronds which measure about 1/2 in. across. The dense
mats of pale green 'leaves' spread rapidly - if left unchecked the whole
surface may be covered, so only introduce this plant where the pond is small
enough for you to remove excess growth by netting. In summer the fronds turn
red and in winter much of the growth is cut back by frost and ice. It is
a good idea to overwinter some of the fern in a jam filled with water and
soil. Reintroduce in April.
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Hardiness: Hardy - survives average winter
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Flower Height Above Surface: -
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Flowering Period: -
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Propagation: Divide clumps of fronds in summer
Hydrocharis-
Frog -bit
Hydrocharis
morsus-ranae
is a good choice for a small garden pond or a minpond - growth is restrained
and a succession of small and short-lived white flowers appear in summer.
In autumn the foliage starts to die away and the plant survives at the bottom
of the pond in the form of dormant buds. In early summer these rise to the
surface and growth begins again. When not in flower Hydrocharis looks like
a tiny Water-Lily; the green kidney-shaped leaves measure 1-2 in. across.
Overwinter some buds in a jam jar filled with water and soil - put back in
the pond in April.
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Hardiness: Hardy - survives average winter
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Flower Height Above Surface: 1-2 in.
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Flowering Period: July-August
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Propagation: Divide clumps in summer
Eichornia-
Water Hyacinth
Eichornia
crassipes
is a menace to waterways in frost-free countries but is a colorful Floater
for outdoor ponds in Britian between June and September. The leaves are dark
and shiny with swollen stems. The late summer flowers are extremely attractive-
strong spikes bear Orchid-like blooms in blue, lavender, and yellow. However,
the catalogue sometimes forget to mention that the flowers fail to appear
in a cool summer. Plant in June and take them indoors before the first
frost.
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Hardiness: Tender - killed in frost
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Flower Height Above Surface: 1 ft.
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Flowering Period: August-September
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Propagation: Remove young plants in Sept. Keep indoors until
June
Lemna-
Duckweed
Duckweed
is in the catalogues, but do take care. You will see
Memna
minor
in stagnant ponds everywhere. A bright green blanket covering the surface.
The usual pattern is a tiny leaf with a root below, and a rapid rate of
reproduction. Several types may be offered by your supplier and they do provide
food for the fish and shade for the water surface. In addition there are
L.
gibba
(Thick Duckweed) and
L.
polyrhiza
(Greater Duckweed). Avoid them like th plague - the only one to consider
is the much less invasive
L.
trisulca.
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Hardiness: Hardy - survives winter
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Flower Height Above Surface: -
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Flowering Period: -
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Propagation: Divide green mat in spring or summer
Pistia-
Water Lettuce
An
easy plant to recognize but a difficult one to grow. It does not thrive in
summer if the temperature is below average and it is rapidly killed by frost
in winter.
Pistia
stratiotes
is the one you will find - not really worth the trouble unless you like to
collect uncommon plants. The lettuce-like leaves are felted and form a floating
rosette on the surface of the pond. The roots are feathery and are a haven
for spawning fish, and the small greenish flowers have no ornamental
significance. Before the first frost of autumn the plants have to be lifted
and moved indoors. Put back at the end of May.
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Hardiness: Tender - killed by frost
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Flower Height Above Surface: -
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Flowering Period: -
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Propagation: Divide clumps in summer
Trapa-
Water Chestnut
Trapa
natans
bears dark green serrated leaves at the ends of swollen stems, each of the
rosettes producing small white flowers in summer. The novel feature of this
plant is that the flowers are followed by 1 in. wide spiny fruits.These black
'nuts' fall to the bottom of the pond where they overwinter and produce new
plants in spring. The plants are annuals and do not survive the late frosts
of autumn; at least that is what some of the catalogues say. In actual fact,
the plant only flowers in a warm summer and the fruits are rearly produced
in our climate.
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Hardiness: Tender - killed by frost
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Flower Height Above Surface: Floating
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Flowering Period: July-August
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Propagation: Drop fruits into the water in spring
Stratiotes-
Water Soldier
Stratiotes
aloides
is a native plant which looks rather like a Pineapple top floating on the
water. The sword-like leaves have serrated edges and it comes to the surface
only at flowering time when white three-petalled blooms appear. When flowering
is over the plant sinks to the bottom of the pond and it overwinters as dormant
buds. In late spring the young plants move upwards, but remain below the
surface when not in flower. Male flowers are borne in clusters - female ones
are solitary. An interesting plant, but it can be invasive where conditions
are favorable.
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Hardiness: Hardy- survives winter
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Flower Height Above Surface: 1-2 in.
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Flowering Period: July
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Propagation: Divide clumps in summer
Utricularia-
Bladderwort
The
bladderworts are unusal plants- they are not easy to find as few suppliers
offer them and they are carnivorous. The finely-divided foliage floats just
below the surface and the bladders on the leaves and stems capture minute
aquatica animals. The microscopic fauna dies and is digested. Yellow flowers
appear in later summer and the plant then dies down, surviving over winter
as dormant buds at the bottom of the pond. In the spring these develop into
young plants which rise and the cycle begins again.
Utricular
vulgaris
is the one to look for- the Antirrhinum-like flowers are deep
yellow.
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Hardiness: Both U. Vulgaris & U. minor are hardy
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Flower Height Above Surface: 9 in.
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Flowering Period: July-August
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Propagation: Divide clumps in summer
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