Irises, also known as irises, can also reproduce via the seeds that grow on the flower stalks. The greater importance of these perennial plants is the root rhizome sitting in the ground, from which new lateral rhizomes grow every year.
How do you divide irises correctly?
You divide irises by carefully digging up the rhizome, cutting it into hand-sized pieces with roots and leaves and keeping the cut surfaces small. After division, you can plant the rhizome parts in the ground with some compost and drainage materials.
Dividing irises for propagation purposes
You can also propagate your irises in the garden via seedlings if you do not cut off the wilted inflorescences before the seeds ripen in late summer. However, it can take up to two or three years after sowing before the first flowers appear on the young plants. In comparison, dividing the rhizomes is a relatively low-maintenance method, which can sometimes result in abundant flowering in the following year.
Get lazy irises going by dividing them
If the irises in your garden produce few or no flowers, then this can have various reasons, such as:
- a location with too little sunlight
- poor soil conditions such as waterlogging
- an overaging of the rhizome
It can be assumed that the rhizome is aging if the site conditions are otherwise good and there are still some flowers in a ring shape around a bare spot. The flowering of irises is usually not a question of nutrients, as the very undemanding plant needs little to no fertilization, depending on the garden soil. If ring-shaped flowers are formed, all rhizomes are dug up and only the outer, young parts are replanted at even intervals in order to fill the bed in a visually appealing way.
The best time to divide irises
You can differentiate between types of irises that bloom early or late. In any case, the time after flowering is ideal for dividing the rhizomes, as long as there is not too much summer heat and drought. This means that the newly planted offshoots can form roots in the new location in the fall and sometimes bloom again the following year.
The correct procedure for dividing irises
Since the shape of the rhizomes cannot be easily estimated above ground, you should not simply prick iris offshoots out of the ground with a spade, as is possible with some perennials in the garden. Dig up the rhizomes as gently as possible with a digging fork so that no leaves break off. Then divide the rhizome by cutting off hand-sized pieces with a clean, sharp knife or spade. Make sure the cut surfaces are as straight and small as possible so that the surface area for germs to attack does not become too large. Sort out the oldest rhizome parts if you don't necessarily want to increase the number of your irises.
Prepare the soil before replanting
Due to their frugality, irises do not necessarily require regular fertilization. However, you will be doing the plants a favor if you loosen up the soil with a little seasoned compost as part of the division propagation and improve its nutritional value. If possible, dig up the soil and add drainage materials such as gravel and sand if the soil is clayey.
Tips & Tricks
When dividing iris rhizomes, you should not overdo it: choose a size for the individual pieces so that each individual part has some roots and leaves. In addition, relatively large cut or broken surfaces also make the rhizome more susceptible to diseases.
