In autumn they are available everywhere again: lush blooming chrysanthemums in many different colors. But did you know that many species and varieties can be cultivated for several years and even overwintered outside? In this post you will learn how to get the flowers through the cold season.
How can you overwinter chrysanthemums properly?
In order to overwinter chrysanthemums successfully, hardy varieties (garden chrysanthemums) should be planted in the garden and covered with leaves and brushwood, while potted chrysanthemums should be kept cool, bright and frost-free. Choose a partially shaded location for a longer flowering period.
Which chrysanthemums are hardy?
Only garden chrysanthemums or winter asters (Chrysanthemum hybrids) are suitable for overwintering outdoors, whereas the so-called pot chrysanthemums are not hardy. But be careful: when it comes to frost resistance, there are also big differences between garden chrysanthemums. Basically, the rule of thumb applies: the later the variety blooms, the better it tolerates frost.
These varieties are considered particularly hardy:
- ‘Bees’: bright yellow flowers
- 'Brockenfeuer': red to brown-red flowers
- 'Goldmarianne': golden yellow to bronze flowers
- 'Little Amber': semi-double, apricot-colored flowers
- ‘Mei-Kyo’: violet-pink flowers
- 'Poetry': semi-double, white flowers
- ‘Switzerland’: pink-violet flowers
The chrysanthemums listed here usually bloom from October, often into November.
How many minus degrees can chrysanthemums endure?
Even garden chrysanthemums that are considered hardy freeze to death above ground when overwintered outdoors. Flowers and shoots can only tolerate frost down to around minus two degrees Celsius. If they are exposed to the cold for too long, these parts of the plant turn brown and die. Therefore, chrysanthemums should be cut off close to the ground either in autumn or in spring at the latest.
They then sprout again from the roots that survive in the ground - as long as the earth is not too frozen due to prolonged deep frosts. Therefore, cover the root area with leaves and brushwood in autumn to ensure a certain level of protection.
Are potted chrysanthemums hardy?
However, you should avoid overwintering potted plants outdoors, even if they are a hardy variety. Due to the small amount of soil, their roots are at risk, as are the above-ground parts of the plant freezing back - in this case the plant will definitely no longer be able to sprout.
Overwinter chrysanthemums in pots as cool as possible, but frost-free in a bright place. The stairwell or a place on a window sill, for example, is suitable for this if the room is unheated. Temperatures between five and ten degrees Celsius are optimal.
When should you plant hardy chrysanthemums?
You should also plant chrysanthemums that are cultivated for several years and are intended to overwinter outdoors in spring - April / May. Then their roots have enough time to take root. However, specimens purchased in autumn should remain in the pot until the following spring and overwinter frost-free.
You don't have the option to overwinter your potted chrysanthemum frost-free? Then you can try this:
- cut down above-ground plant parts
- Cover the root area with brushwood and straw
- Wrap the pot with fleece (€23.00 on Amazon) or similar for winter protection
- Place the pot on a thick wooden board or similar
- Place the vessel on a heat-emitting house wall
- Choose a location that is as protected as possible
Tip
Where should you plant hardy chrysanthemums?
Basically, chrysanthemums can stand in both sun and shade. For the longest possible flowering period, a partially shaded location is recommended, as intense sunlight shortens the flowering period. The spot in the garden shouldn't be too shady, as it quickly gets too cold and too humid, especially in winter.
