The creative design of the swamp and shallow water zone in the garden pond is a challenge even for imaginative hobby gardeners. It’s a good thing that Mother Nature gave us the hedgehog butt. The perennial, evergreen plant surprises with prickly spherical fruits in autumn, which from afar resemble a curled-up hedgehog. The sword-shaped, lanceolate leaves provide a picturesque setting, which optically emphasizes the subtly fragrant, white inflorescence in summer. The following profile shows which attributes characterize the magnificent Sparganium. Practical care information points the way to successful cultivation of this striking aquatic plant.


  • Plant family of tubular bulbs (Typhaceae)
  • Genus: Hedgehog (Sparganium)
  • More than 20 species in Europe, Asia, Africa and North America to Mexico
  • Perennial herbaceous aquatic plant
  • Growth heights in culture from 10 to 100 cm
  • Lanceolate, sword-like leaves, striped or solid and evergreen
  • Single, white flowers, spherical and delicately scented from June to August
  • Prickly, round seed pods in autumn
  • Ball fruits not edible, but slightly poisonous

In addition to its visual advantages, the hedgehog flask scores with an effective contribution to keeping the water clean. The strong, deep-reaching rhizomes hold back mud and sedimented mulm in the ground. In addition, sparganium absorb pollutants from the water and break them down. Therefore, the genus has proven itself as an effective replacement plant for the plant belt in bank, swamp and shallow water zones of swimming ponds.

location and soil conditions

If the body of water extends over an area with different lighting conditions, this fact does not speak against a harmonious planting with hedgehog cobs. The undemanding aquatic plant is tolerant of site conditions as long as its rhizomes are covered with water to a depth of at least 5 cm. Sparganium thrive in these locations:

  • Sunny to semi-shady location
  • Loamy-moory soil, preferably containing clay and rich in nutrients
  • Ideal water depth of 5 to 30 cm
  • The deeper the selected water depth, the more nutrient-rich the water and soil should be

In the bank area and the shallow water zone, the hedgehog develops its optimum as long as it is a standing to easy-flowing body of water. Under ideal conditions, the plant reaches a height of 50 cm and, together with its flowers, stretches up to 100 cm towards the sky. In particular, the favorite for private gardens, ‘Knotty hedgehog’, has this property to line a large garden pond.

Tip: For smaller bodies of water and the bog bed, the popular dwarf hedgehog is there, so that nobody has to do without the impressive plant. This Sparganium species also thrives in sunny to semi-shady locations, but prefers slightly acidic soil and nutrient-poor water.


Against the background of a vehement growth rate, the question of a supplementary nutrient supply only arises in exceptional cases with hedgehog cobs. If you give the aquatic plant a swampy, humus-rich soil, the fleshy rhizomes will conquer the bank area within a few years. The focus is therefore on limiting the urge to spread instead of promoting it with the help of fertilizer.

However, if symptoms of deficiency become apparent, such as yellowed leaves or a stunted flower, the nutrient balance that has gotten out of joint should be balanced. Special preparations are available in specialist shops for this purpose, which are administered to the aquatic plant either in liquid form or better as sticks. Once the plant recovers, stop giving fertilizer.

Tip: planted in an elongated, oval-shaped basket with a diameter of 20-25 cm, the urge to spread of hedgehog ears will not cause you any problems.

To cut

To ensure that the shore and shallow water zone with hedgehog tails retains its decorative appearance and does not dry up as a result of vital growth, pruning takes on a key position within the care program. How to proceed correctly:

  • Remove dead leaves regularly to keep them from contaminating the water
  • Do not cut off wilted inflorescences too early in autumn so that the spherical fruits can develop
  • Ideally, rhizomes that are too long should be shortened in the spring when the sap is dormant

If the habit of Sparganium takes on undesirable proportions during the summer, prune the hardy plant into shape. For a radical pruning, however, early spring is recommended to keep the stress on the aquatic plant as low as possible. Please note that numerous small creatures use the grassy foliage as a retreat. Before the cut is made, the subtenants should be complimented out so that they are not harmed.


When winter calm returns to the pond, the porcupine remains active. The aquatic plant is both hardy and semi-evergreen. It thus takes on the task of maintaining the gas exchange, which is essential for life in water. In addition, Sparganium create eye-catching accents in the otherwise rather barren plant belt, as the prickly fruits can be admired in mild locations well into winter. Successful overwintering is so uncomplicated:

  • Do not cut back hedgehog tails before winter
  • Instead, loosely tie the stems together to keep dry foliage from floating in the water

If you cultivate hedgehog cobs in the narrowly limited volume of a terrace or mini pond, overwintering is a little more complex. Since the water could freeze, which inevitably affects the rhizomes, place the small pond in a frost-free, bright room. If the vessel is too heavy to transport, take the spiked flask out of the water. Planted in a tub or mason’s vat with a 10-15 cm high water level, filled with loamy-muddy substrate, the aquatic plant survives the cold season at temperatures between 0 and 5 degrees Celsius. Under no circumstances should the temperature in the winter quarters exceed 10 degrees Celsius in order to maintain dormancy. In this case, too, only cut back the leaves when they have completely retracted in spring.


Once the multiple strengths of Sparganium are revealed, this creates a desire for more specimens. There are several methods available for propagation, which are explained in more detail below.


Immediately after pruning in early spring is the best time to propagate the hedgehog by dividing the rhizomes. To do this, remove the aquatic plant together with the plant basket from the water. Unpotted and cleaned of the muddy substrate, place the rootstock on a firm surface. You can either split the plant in half or separate runners with at least two buds. Place each section in a plant basket filled with finely silty sand and humus in a suitable location in 10 to 30 cm deep water. Before doing so, cover the soil with coarse gravel so that it cannot be washed out or fish can dig it out.
Tip: For the biological balance in the pond, it is advantageous to settle hedgehogs in a separate part of the tank. Otherwise, hungry fish will dig around in the muddy bottom in search of food. As a result, the water becomes cloudy, the oxygen content decreases and the biotope threatens to collapse.


The targeted sowing of seeds on hedgehog cobs represents a horticultural challenge, since these are cold germs that only start germinating after stratification. You have the choice between direct sowing in the water and cultivation behind glass with a higher chance of success. The two methods at a glance:

direct sowing

In the fall, collect the ripe, prickly fruits to extract the seeds. Without further delay, the seeds are placed 30-50 cm apart in the muddy substrate in a sunny to partially shaded location. Under a thin layer of substrate, the seed remains in the pond throughout the winter in order to naturally experience the cold stimulus required for germination. If the weather is normal, you can look forward to the first seedlings in spring. Right from the start, please make sure there is sufficient distance and a constant water depth of 5 to 30 cm.

Sow seeds on the windowsill

The seed, harvested by hand or purchased from specialist retailers, can be sown behind glass all year round. Follow these steps to do this professionally:

  • Fill a waterproof plastic bowl with mud soil
  • Sow the seeds in it, cover 1-2 cm with substrate
  • Fill up with lime-free water to a level of 1 cm
  • Place in a partially shaded window seat for 2-4 weeks at 20-22 degrees Celsius

With a little luck, the seeds will germinate now. If no life stirs, a stratification is unavoidable. Place the seed pot at 0 degrees Celsius for 4-6 weeks, whereby the water must not freeze through. Then the sowing moves back to the windowsill. To avoid a temperature shock, gradually acclimate the seeds to the higher temperatures. At this point at the latest, the two cotyledons will emerge from the seed coat. Your pupils will be pricked if they have at least 2 pairs of leaves. During this entire procedure, a water level of at least 1 cm is the most important prerequisite for a successful process.

Popular species and varieties

If hobby gardeners are looking for different Sparganium species, they primarily have their divergent growth heights in their sights. For a large- area swimming pond , other hedgehog flasks are suitable than for the small front yard pond. We have put together the most beautiful specimens for you below:

Branchy hedgehog (Sparganium erectum)
The world’s most common species in private gardens. With a growth height of 50 cm, which can increase to more than 1 meter with the inflorescence, this aquatic plant adapts flexibly to almost all site conditions. Thanks to its mighty rhizomes, the branchy hedgehog butt also acts as a natural sewage treatment plant for the water body, as these use up plenty of nutrients.
Special feature : thrives in water depths of up to 50 cm

Simple Sparrow (Sparganium emersum)
This species develops an overall more delicate silhouette than Branch Sparrow. Simple hedgehog caps with a dense, grassy growth that ensures an uninterrupted plant belt.
Growth height : 30 to 60 cm

Dwarf porcupine (Sparganium natans)
The dwarf porcupine is recommended for greening a small body of water with low-lime, slightly acidic soil. As the only species within the genus, it has small floating leaves, so that it knows how to assert itself in the shallow water zone. Under water, the lanceolate leaves reach lengths of up to 60 cm and a width of up to 10 mm. In the bank area, on the other hand, the plant unfolds an upright stature with leaves that grow up to 20 cm long.
Growth height 8 to 30 cm

Thanks to its many advantages, the hedgehog is a premium plant for gardens and streams. Dainty white flowers in summer above elegantly shaped, evergreen leaves, followed by prominent seed pods in autumn; These aesthetically valuable attributes complement Sparganium with a lasting contribution to keeping the water clean.

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