Ranunculus are very beautiful bulbous plants. They bloom in all possible colors and are also suitable as cut flowers. For the gardener, the question arises as to how hardy the flowers are, i.e. how much frost the ranunculus can tolerate.
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The ranunculus ( Ranunculus asiaticus) originally comes from the Orient. This explains why it is less suitable for our relatively cold winters, because the ranunculus hardly tolerates frost. Since the above-ground parts of the plant die anyway after flowering, the air temperature plays only a minor role. Depending on how deep the tubers are, light ground frost up to about minus 5 degrees is not a problem. However, anything below that will freeze the ground and destroy the ranunculus bulbs. They are not sufficiently hardy in our latitudes.
Overwinter in the bed
Ranunculus planted out in the garden bed can tolerate slightly cooler temperatures. That depends heavily on the climate of the area. At locations that get really cold in winter, the ranunculus bulbs don’t stand a chance outdoors. They freeze to death and no longer sprout. The situation is different in more sheltered, warmer locations, for example when there is a wine-growing climate. There, the tubers can remain in the ground if given extra winter protection. This should look like this:
- Ensure good drainage before planting
- Tubers rot in places that are too wet
- Stop fertilizing in the fall
- Cut off withered leaves and old flowers close to the ground
- Cover the ground around ranunculus before the first frost
- with fleece, compost or leaves
- Only remove when no more ground frost is to be expected
It is important for the ranunculus to be able to maintain its natural dormant phase, so the following should be observed when overwintering indoors:
- Clean the ranunculus bulbs
- discard dead, dried-out tubers
- Cut off young spring onions at the same time
- wrap in newspaper or paper towels
- store in boxes in a cool, dark place
- Temperatures not above 5 degrees
- not too moist, tubers could rot
Potted ranunculus doesn’t need replanting after winter, as long as the pot is still the right size. They are simply put back outside. Start watering again slowly to wake the tubers from hibernation. They don’t tolerate too much moisture at once.
Separately kept tubers are watered for a couple of hours before planting. If they look old and dried up after hibernating, that’s not a problem as long as they absorb water and become turgid when watered. Simply discard tubers that still look dry after a few hours in the water.
frequently asked Questions
There are no different varieties of ranunculus, instead they are sorted purely by colour. The variety of colors is now so large due to newer breeds that there is something for every gardener.
They like a slightly moist but not waterlogged soil. Partial shade is better for them than full sun. Watering and fertilizing regularly ensures long-lasting blooms.
Especially in areas where late frost is to be expected, they should not be planted before the end of April. The same applies to plants in pots or tubs, although they can be outdoors during the day when the temperatures are warmer.