Bearded Irises - Reproduction And Cultivation

2024 Author: Sebastian Paterson | [email protected]. Last modified: 2023-12-16 13:47

Agrotechnics of bearded irises

Iris nutrition

I have been cultivating bearded irises for many years and I want to share my experience with beginners - to talk about what factors contribute to the normal development of plants and their lush, bright flowering, as well as those negative moments that can lead to the death of irises.

As with any perennial plant, iris is fed during its growing season, i.e. at temperatures above 5-8 ° C. It is during this period that you need to provide flowers with the elements they need.

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At the beginning of the season, iris requires nitrogen, potassium, then it needs phosphorus and potassium, since with a late supply of nitrogen, the immature rhizomes are more watered (fattening occurs), contain less dry matter and are more susceptible to frost. Scientists call this phenomenon "cryoscopy" - an increase in the freezing point of a solution compared to a solvent. In this case, the solution is protoplasm with carbohydrates, proteins, etc. contained in it, and the solvent is water.

The irises need to be fed all summer. I do this with low concentrations of Kemira - total fertilizer without chlorine of 20 g / 10 l per 1 m2. There is no need to do any break after flowering, since it is at this moment that the inflorescence of the next year is laid and the second wave of root growth begins.

Reproduction of irises

Varietal irises reproduce vegetatively, in divisions with leaf fans. In the Northwest, division must be carried out immediately after flowering and cutting the peduncle, i.e. before the formation of new roots and inflorescences of the next year. This time is individual for each variety and depends on the flowering period.

Such delenki have time to take root and, with good care, lay an inflorescence without injuring the roots during transplantation. If you do not follow the terms of division and the conditions of transplantation, the quality of the inflorescence of the next year will deteriorate.

Reproduction can be accelerated by kidney grafting. This will be facilitated by "surgical techniques": autumn elimination of apical (head) dominance in the rhizome, which contributes to the awakening of dormant buds. Covering with a film in the fall helps to prolong the growing season and causes earlier awakening and growth of dormant buds.

The vitality of culture

Newly supplied luxurious iris varieties that have not undergone acclimatization require special attention. Their vitality is determined by two interdependent factors: winter hardiness and immunity to bacterial rot.

Bacteriosis

Bacteria that cause wet rot do not have enzymes to dissolve the rhizome membrane, but move and feed on the entire cell membrane in the aquatic environment. The optimum temperature for their life is 20 ° C.

When they penetrate the rhizome through microcracks, they secrete enzymes, process nutrients, multiply, moving around and capturing new areas, turning the rhizome into a rotten mass with an unpleasant odor. Outwardly, it looks like a "falling fan". The development of bacteriosis can be combated by preventive measures.

Requirements of irises for the planting site and soil

Plant bearded irises in areas exposed to the sun. Provide good drainage of the soil by adding sand, which excludes injury to rhizomes by water crystals (after thaw and the onset of frost). To exclude the introduction of fresh manure, which is poisonous for the roots, under irises (except for horse manure, which does not contain excess ammonia). Eliminate the "fattening" of plants from excess nitrogen.

The increase in winter hardiness of bearded irises occurs with an increase in the concentration of nutrient (dry) substances in the rhizomes. It depends on the following factors:

Ensuring the duration of the growing season, contributing to the ripening of the rhizome (the flowering period of the variety, covering with a film, reducing watering and the dose of nitrogen application). A good shelter from rain does not allow the rhizomes to be additionally saturated with water and, of course, it also serves as a shelter from frost. The inclusion of phosphorus and potassium in the last dressing promotes the outflow of nutrients into the rhizome and helps it ripen.

What to do if wet rot still appears on your flower beds with irises? Cut off the sore spot so that the cut is illuminated by the sun.

Treat the cut with activated carbon, because coal is a good adsorbent, removes moisture, drying the cut, and prevents microbes from moving. The sun dries the cut, and at a temperature of 45 ° C it has a bactericidal property.

Trichopolum (metronidazole) can be used to treat the cut and the entire rhizome. This antibiotic against protozoa and gram-negative bacteria (2 tablets per 1 liter) is already used by amateurs.

By winter hardiness and resistance to diseases P. F. Gothenberger divides all irises into three groups: resistant, less resistant and non-resistant.

By immunity, irises are also divided into three groups. The first group includes varieties affected by bacteriosis by less than 10%, the second - from 11 to 49%, and the third - more than 50%.

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To the first group of old, viable, frost and disease resistant varieties P. F. Gothenberger classifies the varieties of the company "Gus-Keneman", created at the beginning of the XX century, and some varieties of foreign breeders of the USA, England and France, which have been growing here for many decades, and then passed natural selection in the Baltic conditions.

These varieties during the harsh winter of 1978-79. in the suburbs, when the temperature dropped to -40 ° C, they survived, and many varieties of new foreign selection died.

Varieties of this group will winter well if they are covered with soil by 10-15 cm and planted in drained soil, preferably on a sand cushion.

The second group includes varieties of irises that are sufficiently adapted to our conditions, which remain "in use" and grow without any problems. These include Steppes Out, Blastin Beauty and others.

However, the famous St. Petersburg iris grower and breeder G. I. Rodionenko told about the death of 150 varieties not covered in November 1993, when for two weeks the ground was without snow, and the frost was -17 … -23 ° С.

Therefore, adapted varieties also require cover with a 10-15 cm layer of earth and spruce branches or leaves in case of force majeure.

The third group includes new, not yet acclimatized varieties. Preventive measures against wet rot and dry shelter are especially important for them.

I'll tell you about cases from my floriculture experience. The new varieties Avelon Sunset, Anna Bela Bobson, planted under the film, were forgotten by me, and winter brought a surprise: at the end of January, the snow completely melted, and then for two weeks it was -30 ° С.

In the spring, I was very surprised to see that my irises were still alive: Avelon Sunset and Anna Bela Bobson even bloomed, but gave a short peduncle. This gave me confidence in the possibility of growing these varieties in our climate and confirmed the high winter hardiness of the matured dry rhizome (the flowers were covered only by 7-10 cm with earth and a film at a height of 70 cm).

I must also say about the negative consequences of the "bird cherry cold". I believe that covering flowers with lutrasil can be a very good protection for already growing plants at negative temperatures with the wind. Usually, such phenomena cause physiological drought and stop the process of chlorophyll formation (leaves turn white).

For example, P. F. Gothenberger writes that an exhibition of irises did not take place in Riga in 1990, since all flower stalks of the extra-class varieties died at -6 ° C, except for the varieties of the German company "Gus-Keneman". It happened in the spring. Apparently, covering the plants with lutrasil would have avoided this.