Forcing irises at home – is it possible?
In Moscow, at the station of young naturalists, there is a school of ecologists-researchers. The guys from the floriculture section have been learning the technology of forcing flowering plants for 5 years. Having taken up an absolutely unfamiliar business for themselves at first, they checked everything that was recommended in the special literature, which, by the way, is not so much. Young flower growers-researchers perfectly mastered the forcing process. We have found the most effective, rational way to grow irises at home.
When the irises bloomed, everyone came to look at them. It is one thing to see flowering plants in the summer in the garden, and quite another to grow them in the classroom or at home in early March, when there is still snow outside the window. Irises stood on our floor in large special vessels for distillation and resembled a flower bed. Many were surprised how irises bloom at such an inopportune time? We explained that we are forcing flowering plants, and growing irises at home is not a myth, but a reality.
What is “forcing”?
There is general information about what forcing is that all novice flower growers need to know. Plants of the temperate zone in winter at low temperatures are at rest. But among them there are many who lay flower buds by winter and bloom in early spring. However, if you change the conditions and first of all increase the temperature and humidity, then the plants that have flower buds will bloom in the winter in the house. To create such conditions, you can use basements, sheds, shelves of household refrigerators, that is, rooms with a low positive temperature. For distillation, we used undersized purple irises that bloom in late May and early June (simultaneously with lilacs).
Biological features of irises
Iris is a perennial, herbaceous plant wintering in the open field. His underground organ is a rhizome, which spreads horizontally over the surface of the soil and only partially goes deep into. It consists of thickened and shortened segments (links), often reaching a significant size (8-12 cmin length, 2-3 cmin diameter).
In some parts, the rhizome grows, in others it slowly dies off. Adventitious roots live 2 growing seasons, they are no longer on the 3-year-old link. At the top of the annual segment of the rhizome, after the drying of the peduncle, depressions remain. By annual links, you can determine the age of the plant.
The flower bud is located in the apical part of the leaf bundle (fan) and is laid 3-4 weeks after the end of flowering. Irises bloom intensively next year, which means that everything in the distillation is decided by the weather of this period. If the weather is warm and dry in June – early July (for early varieties), the plant will lay more flower buds. In damp and cool weather, fewer buds will form.
Here is a very important information from the literature on growing irises, which we did not pay attention to at first and therefore did not receive flowers when forcing in one of the years: flower buds are laid only in fans of 7 or more leaves.
We knew that in order for irises to lay flower buds well, it is necessary to pay attention to the conditions for their cultivation. From their ancestors, bearded irises inherited a love of warmth and light. They grow best in a sheltered, sunny location with well-drained soil. The sun’s rays of the first half of the day are especially useful for irises. The upper part of the rhizome (back) must be in the sun. Irises can tolerate light shade from sparse trees, especially during the hot afternoon hours, but they cannot tolerate heavy shade at all and stop blooming, although the foliage develops. Watering irises is required only during a drought, usually they have enough precipitation. The exception is the mandatory watering at planting, during the budding period and top dressing. Iris is not picky about soil conditions, but grows better on clay nutrient soils.
By providing the above conditions for irises, you can grow good planting material for forcing.
How to avoid mistakes when forcing irises
In the first years of research, we took planting plots from overgrown perennial bushes. Flowering at home in winter was obtained, but unstable in different years and with a low percentage of flowering shoots. The explanation for this is that the rhizomes are crowded in a large bush and few leaves are formed, which means that flower buds are poorly laid. This prompted us to think about growing planting material specifically for forcing. Three weeks after flowering, which falls at the end of June – beginning of July, we divided the perennial bush and planted annual and biennial shoots of rhizomes on the ridges. In September, the plants from the ridges were planted in vessels (boxes are possible) and left dug on the ridges until frost. In early November, the irises were removed to the basement (+4°C). During storage, make sure that the earth in the vessels does not dry out.
Flowering began at the end of February. The grown annual and biennial shoots bloomed profusely. Ungrown one-year-old shoots did not bloom at all, and two-year-old shoots bloomed very weakly compared to the grown ones. So, empirically, we determined that it is better to grow planting material for distillation.
In 1998-1999 set up another experiment to find out how the age of germinated planting material affects the flowering of irises in forcing. One-year-old, two-year-old and three-year-old shoots were planted.
We call an annual shoot a juvenile (not yet flowering) shoot of an annual growth (one apical link of a rhizome with a fan of leaves). A two-year shoot is a juvenile shoot of one-year growth with last year’s growth (two links). Three-year – juvenile shoot of one-year growth with growths of the previous two years (three links).
Before planting in distillation vessels, the number of leaves in the fans of each plant was counted. Annual shoots had from 3 to 7. Apparently, the conditions of the summer of 1998 (drought) did not contribute to the growth of leaves. Therefore, flowering in winter was very weak.
Two-year-old shoots had 5 to 10 leaves. Irises from these shoots bloomed profusely – 80% of them gave flower stalks, most plants had 2 peduncles.
Three-year-old shoots bloomed well, but weaker than two-year-old shoots – 70% gave flower stalks and there were fewer flower stalks.
Thus, it turns out that one-year-old shoots, even germinated ones, may not bloom well every year when forcing, while the cultivation of two-year-old shoots ensures abundant and stable flowering.
Recommendations for forcing irises at home
- For forcing irises at home, take the usual bearded purple irises that bloom in late May – early June (simultaneously with lilacs).
- At the end of June, plant (for growing) on a bed in a garden or vegetable garden apical annual shoots with a fan of leaves. Leaves shorten to 10-15 cm. These plantings remain for next year.
- In the spring and summer of the following year, take good care of the plants so that as many leaves as possible grow in the fan.
- In September-October, two-year-old bushes are transplanted into boxes, vessels, flower pots and left in the open ground, but do not forget to water. Choose plants that have 7 or more leaves in a fan. In early November, bring the irises into the basement or other frost-proof room (4-6 ° C).
- During storage, do not forget to water the plantings, do not let the earth dry out.
- Carry out the forcing at the beginning of February, that is, transfer the plants from the storage place to a warm, bright room with an average room temperature.
- In early March, irises will bloom.