The sun rose, which requires little care, shimmers in the brightest colors. Yellow, orange, red, pink, white and dark red varieties are now commercially available. But what about their winter hardiness?
Are sunflowers hardy?
Most sunflowers are hardy and can survive temperatures down to -20 °C. However, some sensitive varieties, such as the moonspot sunflower, require light winter protection, for example with brushwood, straw or mulch. Sunflowers should also be protected from winter sun and moisture.
Sunflowers are frost hardy down to -20 °C
Most common sunflowers are hardy and perennial. Many specimens even survive frost down to -20 °C! The following well-known sun roses are considered to tolerate frost well and generally do not need winter protection:
- Common Sunflower
- Yellow Sunflower
- Apennine sunflower
- Mountain Sunflower
- Hybrid 'Yellow Pearl'
- Hybrid ‘Roseum’
- Hybrid 'Firedragon'
Protect sensitive varieties from severe frost
But there are also varieties that are more sensitive and can sometimes cause frostbite if left unprotected. These include, for example, the moonspotted sun rose. It needs light winter protection. Many hybrid varieties that have double flowers are also sensitive to frost.
Basically, you should protect your sunflowers in winter if they are in rough locations, were freshly planted in autumn or were freshly propagated, for example from cuttings, and are standing outside.
The right winter protection
But how should you protect the sensitive little sunflowers from severe frost? Fir and spruce branches, brushwood from deciduous trees and straw are well suited. The material is simply placed loosely on the plant.
Alternatively, a layer of mulch in the form of gravel or chippings, which was laid in spring, is also helpful to protect the plants from frost. Apply the winter protection before the first frosty nights in autumn.
Prepare for winter – cut back
Before winter sets in, you should grab the scissors. Cut back the sunflowers. This means they are better protected in winter and in spring they can start the new season with compact growth.
Be careful of winter sun and moisture
In addition to severe frost, there are two other points that sunflowers don't like or tolerate at all. This includes, on the one hand, winter sun. The warmth of the sun stimulates budding. If it is night, the fresh shoots will freeze. On the other hand, sunflowers quickly become damaged if they are left in wet soil for days in winter. Keep them safe from this!
Tip
There are even beautiful wintergreen varieties of sun rose. This includes, for example, 'The Bride' with its silver-colored foliage.
