Forcing Iris reticulata

When to force your Iris reticulata bulbs?

If you want to make your reticulate Iris bloom for Christmas or New Year, you need to plan ahead. Ideally, start forcing the bulbs of Iris reticulata during the first half of October.

How to force a reticulated iris bulb?

To make a bulb of Reticulate Iris flower before its usual flowering period, it must undergo a cold period. To achieve this, you need to simulate winter by placing the bulbs in a cold, dark place, such as the refrigerator. This location should maintain a constant temperature of between 2 and 10°C. Generally, all varieties of Iris reticulata can be forced. It is important to choose high-quality bulbs that are firm and of large size (5/+).

Required Materials:

• Bulbs of Iris reticulata
• A wide, shallow pot or container (maximum 15 to 20 cm) for planting the Irises in groups
• Clay balls or gravel
• Horticultural compost
• Sand

Forcing:

• Ensure your pot has drainage holes to allow excess water to escape. For good drainage, place a layer of drainage material at the bottom of the pot, such as clay balls or gravel.
• Fill your pot with substrate to about 2/3 of its height.
• In the container, place the bulbs the right way up, that is to say with the tip facing upwards and without them touching. Space them about 3 cm apart.
• Cover with compost and then add a layer of sand to reach the rim of the container.
• Water.
• Place the bulbs in a cool, dark location that will serve as a cold chamber, such as a refrigerator or unheated cellar, for several weeks until the young shoots appear in a light yellow colour. If you are forcing your bulbs in the cellar, cover them with a black plastic bag or cardboard to ensure good darkness. This process lasts between 6 and 8 weeks, depending on the temperature. During this phase, remember to keep the substrate moist by watering sparingly. If you place a saucer under your pot to avoid dirtying the bottom of your vegetable drawer, remember to empty it after each watering. This prevents the substrate from becoming waterlogged, which could cause the bulbs to rot.

In the refrigerator, avoid placing your bulbs near ripening fruits or vegetables that produce ethene gas, as this can damage the bulbs.

Bulbs of Iris reticulata

What to do after forcing Iris reticulata?

When the shoots are about 5 cm tall, it’s time to take your forced Iris reticulata pot outside.

• Place your forced reticulate Iris in a not too warm location in the house (between 15 and 20°C) and bright, near a window for example, but out of direct sunlight. Be careful, the flower stem may become leggy if it doesn’t receive enough light or if there is excessive heat.
• Rotate your pot a quarter turn every day to allow the Iris to develop evenly.
• Water when the substrate is dry.

The Iris reticulata should flower in about two to three weeks, depending on the temperature of your room. Your Iris will then fill the house with fragrance! However, be aware that the flowering will be brief, with the flowers lasting only 5 to 10 days.

Shoots and flowering of Iris reticulata in pot after forcing

What to do with Iris reticulata bulbs after flowering?

Forced reticulate iris bulbs are sold out. To allow them to store energy, you can replant them in the garden, but it is important to know that they will not flower the following year. You will need to wait 2 or even 3 years before seeing them bloom again.

For further reading

• Find all our tips for growing Iris reticulata in pots
• Discover all our tips for planting Iris reticulata in the ground