The number of types of algae that are up to mischief in the garden pond is long. Algae are at their best when there is a high stock of fish, plenty of food, a considerable nutrient content and sparse planting. The water becomes greenish-cloudy, which completely destroys the aesthetic effect of the pond as an oasis of well-being. As long as the body of water maintains the biological balance, they exist in peaceful coexistence with plants and animals. Only an excess of nutrients triggers the dreaded bloom of algae. In order to prevent this disaster, knowledgeable hobby gardeners deliberately plant pond plants against algae, which of course only fulfill their task if the instructions for planting, care and overwintering are heeded.
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Functional plant arrangement
When the knowledgeable hobby gardener draws up the planting plan for his garden pond, he is pursuing two central goals. On the one hand, he wants to create a harmonious, flowery look; on the other hand, heavily consuming pond plants against algae are in focus. It is therefore important to put together a strategically clever mix of aquatic plants for the bank area, for the shallow water and the deep water zone, which ideally fulfills both requirements. The following list offers an excerpt from the multifaceted variety of suitable plant species and varieties.
Marsh plants for the riparian zone
- Sumpfiris (Iris laevigata)
- Small or large bulrush (Typha)
- Igelkolben (Sparganium erectum)
- Zwergbinse (Juncus ensifolius)
- Binse (Juncus)
shallow water plants
- Kalmus (Acorus)
- Tannenwedel (Hippuris vulgaris)
- Pfennigkraut (Lysimachia nummularia)
- Schwanenblume (Butomus umbellatus)
- Riesenvallisneria (Vallisneria gigantea)
Deep Water Plants/Underwater Plants
- Hornkraut (Ceratophyllum demersum)
- Milkhopper (Myriophyllum aquaticum)
- Dense-leaved waterweed (Egeria densa)
- Canadian waterweed (Elodea canadensis)
- Seerose (Nyphaea)
- Algenfarn (Azolla spec)
- Froschbiss (Hydrocharis bite-frog)
- Wasserhyazinthe (Eichhornia crassipes)
- Three-furrowed duckweed (Lemna trisulca)
- Floating fern (Salvia natans)
- Sternlebermoos (Riccia floating)
These heavily depleting pond plants deprive the algae of their basic nutrients due to their considerable consumption of nutrients. The extent to which they are planted depends on the size of the body of water and the number of fish and other creatures that live in it.
marsh and riparian plants
In the swamp and bank zone of the garden pond there are plant species that on the one hand act against algae and on the other hand enjoy widespread popularity. This includes the popular cattail or the bulrush. Thanks to the good accessibility, the garden lover doesn’t mind that they thrive so vigorously.
- Thin out withered, dried up and dead plant parts.
- In autumn, cut back radically to the ground.
- If necessary, dig up the rhizomes and shorten them.
Other perennials in this area often also thrive in conventional perennial beds, such as the marsh iris, also known as marsh iris. At this location, they are cut back before winter, just like in the bed.
shallow water plants
In the shallow areas of the garden pond, annual beauties such as sweet flags can be found, which are usually not cut. At the same time, creative hobby gardeners settle robust fellows here, such as the hardy fir frond, which bridges the cold season by pulling in the shoots without further ado. Accordingly, this plant is only cut in the spring before the new shoots. If the water level is not too high, flowering perennials will also spread on this terrain, which also adorn the bed, like pennywort. With these plants, gardeners use the classic method of pruning before winter.
Deep water and underwater plants
Well-known representatives among the pond plants against algae that are cultivated in deep water are the waterweed and the water lily, which are cut according to completely different criteria.
- Prune and thin out rampant underwater plants regularly.
- Prune most of the growth before winter to prevent rot.
- Get the water lilies out of the water and trim the roots or rhizomes.
- At the same time, thin out the stems and leaves of the water lily.
Depending on the water lily species or variety, pruning is only necessary every 2 to 3 years.
Since these plant species float on the water and are not rooted in the ground, the hobby gardener brings them in with the net to carry out the pruning. He also takes this opportunity to remove all stunted or diseased parts of the plant. Depending on the weather conditions, their spread progresses quite quickly. As a rule of thumb for floating plants that act against algae, one third to a maximum of half of the pond surface should be overgrown. Experience has shown that a single pruning in autumn is not enough for Wasserpest and colleagues.
Cutting pond plants against algae is therefore not carried out with military precision, but is tailored to their individual habit and their specific needs.
Garden lovers have the choice of planting their pond plants directly in the substrate or with the help of special plant baskets. It is advisable to plant hardy plants, which stay in the water all year round anyway, directly in the pond soil. In mini and patio ponds, the lack of space alone requires this procedure. This is possible every year within the bank and shallow water zone of powerful facilities. In the deep water area of a large pond, the experienced hobby gardener carries out the planting as part of the new system. Cultivation in a basket is ideal for specimens that are not hardy, because in this way they can move to their winter quarters without much effort.
- The best time to use pond plants against algae is late spring.
- Simply place floating plants on the surface of the water.
- Put rooted plants in the right water depth in the soil.
- Only plant the leafless root area and cover with gravel.
- Alternatively, line plastic baskets with jute and fill in the substrate.
- Do not use commercially available potting soil, but low-nutrient pond or clay soil.
- After planting, weigh down the substrate with pebbles or gravel sand.
Ideally, the experienced hobby gardener gradually acclimates the pond plants to the cool water. He supports the plant baskets with stones at the beginning in order to gradually lower them to the ground. Aquatic plants planted in the ground should – if at all possible – be flooded over the course of several days so that the sensitive roots do not suffer a cold shock.
The primary task of pond plants against algae is the maximum absorption of excess nutrients that get into the water via a wide variety of routes. Scheduled application of fertilizers would play into the hands of algal blooms. As a result, the informed hobby gardener only fertilizes when it is absolutely necessary. If signs of deficiency appear on the aquatic plants, such as yellow leaf tips, laziness in flowering, dull colors or stunted growth, all other causes are examined in advance in the process of elimination. A shady location, a dark, rainy summer or water that is too hard are also possible triggers for pond plants not doing well.
- Only fertilize pond plants if there is no doubt that there is a lack of nutrients as the cause.
- Keinen herkömmlichen Pflanzendünger verabreichen, sondern individuellen Teichdünger.
- Vorzugsweise Flüssigpräparate verwenden, statt Stäbchen, Düngekegel oder Tabletten.
An die Dosierung geht der sachkundige Gartenfreund vorsichtig heran. Nachdüngen ist wesentlich unkomplizierter, als eine Überdüngung wieder rückgängig zu machen. Darüber hinaus dürfen die Mittel nicht in direktem Kontakt zu Pflanzen gelangen, weil in diesem Fall Verbrennungen drohen. Sobald die Teichpflanzen signalisieren, dass sie sich erholen, wird die Gabe von Dünger eingestellt.
Die Arten- und Sortenvielfalt an Teichpflanzen gegen Algen erstreckt sich über ein breit gefächertes Spektrum. Entsprechend differenziert geht der geübte Gartenfreund an den Schnitt heran. Zentraler Zeitpunkt für den Rück-, Auslichtungs- und Formschnitt ist der Herbst, wenn der Teich ohnehin winterfest gemacht wird. Stark wuchernde Wasserpflanzen werden im Verlauf der Vegetationsperiode wiederholt gestutzt, um ihre Ausbreitung zu regulieren. Gewächse mit einer langsamen Wuchsgeschwindigkeit erfahren hingegen nur alle paar Jahre einen Rückschnitt.
The propagation of plants in the garden pond usually does not pose any major problems. The best time to do this is usually early summer. Reproduction during the winter, as is sometimes the case with perennials or shrubs, is largely hopeless in the pond due to the danger of the water freezing.
- Cut cuttings to a length of approx. 15 cm.
- Defoliate the lower part and stick into the pond soil.
- Then cover the planting site with gravel sand.
- Simply place offshoots of floating plants on the water.
- Cut off root pieces with at least 1 to 2 buds.
- Fill plant pots with a clay-sand mixture.
- Press the rhizomes into the substrate.
- Sprout in a water box in a warm, partially shaded spot.
- After approx. 1 month put the young plants in baskets in the pond.
- Take or dig up suitable perennials from the plant basket.
- Divide with a spade or a sharp knife.
- Use and cultivate each segment as an independent plant.
In particular, the division serves to propagate at the same time as a rejuvenation measure for pond plants such as the water lily. Even if no further specimens are desired, the attentive hobby gardener divides them every few years, which considerably extends the lifespan of the ‘queen of pond plants’.
Native aquatic plants against algae consistently prove to be hardy. They pull in their shoots or form winter buds (turions) that remain on the ground to thrive again the following spring. After they were allowed to enjoy a pruning and thinning out in autumn, they stay in place during the cold season. With exotic perennials, the situation is somewhat different, because they start to freeze at 10° Celsius. By the beginning of winter at the latest, the garden lover will be happy about his decision to cultivate the immigrated pond plants in the basket, because it makes the move to the winter quarters much easier.
- Bring out non-hardy pond plants in good time before winter.
- A sufficiently large aquarium serves as exemplary winter quarters.
- A repurposed vat, old zinc tub, or similar is acceptable.
- Overwinter in a cool room and put back in the pond in mid/end of May at the earliest.
In the event that a compact ice cover forms, experts recommend placing an ozonizer at the bottom of the pond. This device releases oxygen gently and in small bubbles, which prevents the formation of fermentation gases. Under no circumstances should a hole be punched into the ice surface. The pond plants don’t mind the noise, but the fish are literally ‘scared to death’. Hot water, which melts a small opening in the ice, works more effectively. Then pump out enough water with the hose of the water pump so that an approx. 20 cm thick insulating layer of air forms, which absorbs the fermentation gases produced.
An algal bloom can vehemently spoil the joy of a lovingly designed garden pond. Algae are also plants, which of course create an appearance that goes beyond all aesthetics. So that it doesn’t get that far in the first place, the experienced hobby gardener consistently plants pond plants against algae right from the start. In terms of nutrient consumption, they compete with the green mites and keep their growth in check.