The swamp iris grows as a perennial, herbaceous plant with heights of approx. 100 cm. In addition to its sword-shaped leaves up to 90 cm long, it impresses above all with its typical, rich yellow iris flowers, which it presents between May and the beginning of July. Thanks to its creeping and persistent rhizome, it forms larger populations in a short time, provided that the location and care meet its requirements.
Characteristics
- Plant family: Iris family (Iridaceae)
- Botanical name: Iris pseudacorus
- Common names: water iris, yellow iris, pond lily, swamp lily
- Habit: persistent, herbaceous, horizontally creeping rhizome
- Heights of growth: 60-100 cm
- Flowering period: May to July
- Flower: single flower, yellow dome and pendulous leaves, black-brown markings in the middle
- Leaf: broad, sword-shaped, pointed, shedding leaves
- Limescale tolerance: Limescale tolerant
- Toxicity: toxic in all parts
Location
As the name suggests, this iris feels in the swamp or most comfortable in the swamp zone of a garden pond. It should be in a sunny to partially shaded part of the garden. In this case, swamp zone means in a water depth of 10 to a maximum of 20 cm.
A place at the edge of a pond, an artificial stream or generally in garden areas with muddy or constantly moist soil is also suitable. In general, this plant also copes well with changing water levels and water depths of up to 40 cm, but the flower formation is then significantly less. For a short time she is satisfied with a drier place on the bank edge.
floor
The iris is a typical swamp perennial and therefore thrives best in heavy and wet clay soils. It copes better with acidic to slightly alkaline soils than with too calcareous soils, although they have a certain lime tolerance. As long as the soil is permanently moist to wet and it can store moisture well, it can also stand well in the garden soil. In addition, the soil should be rich in humus and nutrients.
Tip: The respective soil should not dry out completely if possible. Especially drought in spring can have a significant impact on flower formation.
planting
Best time to plant the pond lily (Iris
pseudacorus) is in both March and August to mid-October. When planting, the rhizome can be inserted horizontally just below the top soil layer or in a planting basket beforehand. The latter has the advantage that the plants cannot spread too much because they are very vigorous.In addition, they are easier to remove from the pond and less competitive neighboring plants are protected. Regardless of the type of planting, you calculate about two plants per square meter. For planting in a basket, you need a plant basket, some fleece, washed, lime-free pebbles and a special pond substrate.
- Sales pot unsuitable for permanent pond planting
- Wire mesh planter ideal
- Should be a little bigger than the ball or the rhizome
- Use plants soon after purchase
- If there is a delay, dip the swamp lily in water and store in a plastic bag
- First line the basket with fleece as protection against flooding
- Then fill in some pond soil and insert pond lily
- Fill up to 2.5 cm below the rim of the basket with soil
- Commercially available potting soil or potting soil too rich in nutrients
- An excess of nutrients would promote the growth of algae
- To weigh down, fill in gravel as the top layer
- Place the basket slowly in the pond at the appropriate depth
- Note the maximum planting depth, otherwise there is a risk of rot
- Plant spacing of approx. Maintain 40 cm
Tip: Correspondingly larger baskets can easily be equipped with several plants and placed in the pond. Lime-free gravel and broken clay granules are good alternatives to pond soil.
Care instructions
With proper care, the swamp heavy lily will also have a long and healthy life.
Watering and fertilizing
Once rooted, the pond lily is very undemanding and easy to care for. Specimens in the pond are usually neither watered nor fertilized. If the plant is outside a pond, on suitable soil, it is important to fertilize it regularly. By the way, swamp irises love nitrogen. It is best to give a sufficient dose of humus in spring at the start of budding
or mature compost. It is poured in such a way that the soil is constantly moist and does not dry out completely and permanently.Cutting and wintering
A normal pruning as with other plants is not possible and also not necessary with the swamp lily. In most cases it is sufficient to cut old leaves from the plant in spring. They should be preserved over the winter. In autumn, remove all withered and dried up parts of the plant, including the fruit stands, in order to avoid uncontrolled spread. If you need seeds for propagation, you can let some seed heads mature on the plant. As far as frost resistance is concerned, this plant, which is predestined for the swamp or pond, is hardy down to minus 29 degrees. As a result, it gets along very well without any winter protection.
Tip: This plant is poisonous in all parts, especially in the area of the roots. As a result, gloves should be worn when cutting or handling it.
Multiply
There are different ways to propagate the iris iris, here you can find out how to do it.
sowing
One form of propagation is via seeds. These can be purchased in stores or obtained in autumn from the ripe fruit capsules of existing plants. They should be sown as soon as possible after harvest.
- Best time to sow from October to December
- Harvest seeds as soon as the ripe fruit capsules burst
- Then soak in water at room temperature for 4-5 days
- Seeds need a cold stimulus to germinate (frost germinator)
- To do this, sow in small pots with a sandy-loamy substrate or sand
- Then moisten the substrate
- Put pots in the refrigerator or directly outside for several weeks
- The effects of frost in winter are important for germination
- Cover with snow if necessary, if present
- The seeds should not dry out until they germinate
- Germination occurs the following spring
- The first seeds often germinate after about a month
As soon as the seedlings have reached a size of 3-4 centimeters, they can be isolated in nutrient-rich substrate. They can be cultivated in a frost-free room until spring. Above all, it is important to ensure that the substrate is kept evenly moist. Or you put the pots in a bowl with enough water, which you refill from time to time. In May / June the young plants can then be placed in plant baskets and then in the garden pond. It can take between three and six years for plants propagated through sowing to bloom for the first time.
Tip: Pond lilies can also reproduce very well on their own thanks to their buoyant seeds and creeping rhizome.
division
The swamp lily is one of the swamp perennials that spread the most, so that a division may be necessary in order not to overly pressurize neighboring plants. Or you just split them up so that you can plant them out in different locations. The best time to do this is during the dormancy period in spring. The thick-fleshed rhizomes are divided.
- It is recommended to divide every 3-4 years
- Iris otherwise at some point lazy to flower
- Best time in spring
- First, dig up the plant generously
- Or lift the basket out of the pond
- Take out of the basket and remove any debris
- If necessary, rinse with a garden hose
- Remove damaged and dead root parts
- Divide the rhizome with a spade or sharp knife
- Each section must have roots
- Use newly obtained plants separately from each other
- When planting without a basket, a spacing of 40 cm is advisable
Diseases and pests
If the Iris pseudacorus is in the right location and receives sufficient moisture, there is no risk of infestation by pests or diseases. However, the conditions are often anything but optimal, which opens the door to pests. If the plant lacks moisture, it can be problematic. It hardly grows or does not grow at all and flowering could also fail completely. The pests that can attack this iris include the iris weevil and the iris sawfly in particular.
Iris weevil
The iris weevil grows up to five millimeters in size and has white spots on its back. It occurs mainly in the summer months. The actual pests, however, are their larvae. They dig into the buds to systematically hollow them out. If you look closely, you can see the entrance to the feeding passage from a dark brown point. In most cases, direct control is not necessary. Usually it is enough to read the beetles.
Iris sawfly
The larvae of the iris sawfly are also the ones that leave ugly traces of food on the leaves of the swamp sword lily. Depending on the severity of the infestation, they can eat these plants completely bare. There are no suitable means of control, and in some federal states these animals are even on the Red List of Endangered Species. The only thing you can do is read the wasps and cut the eaten leaves off the plant. In ponds stocked with fish, the larvae can also be sprayed with a stronger jet of water, because they are a coveted delicacy for fish.
Good companion for the swamp iris
With the right companion plants, the swamp iris comes into its own even better. When choosing the right plants, make sure that they don't get too tall and cast too much shade. They should not form runners themselves, so as not to constrict each other. For the damp edge of the water or pond or the shore area is suitable, for example, of the approx. 20 cm high penny loosestrife, the 80 cm high false cyprus sedge and other clump-forming Carex species. In addition, the up to 150 cm large loosestrife (Lythrum salicaria) and smaller rush species (Eleocharis) are suitable plant neighbors.
Exceptional abilities of this impressive plant
The swamp sword lily Iris pseudacorus is a so-called repositioning plant. This means that it is used on the one hand as a holding plant for bank stabilization and, in particular, for water purification. They serve as natural soil filters in garden, swimming and koi ponds as well as in sewage treatment plants. In doing so, they absorb pollutants from the water and slowly break them down again. In this way they contribute to a nutrient balance in the garden pond. Their roots also provide a habitat for numerous small water dwellers.
Tip: Swamp sword lilies in the wild are under nature protection and may only be removed there with permission. This is also not necessary, because the gardening trade offers a variety of attractive cultivation forms.