Depending on the variety, hydrangeas need winter protection to survive the cold season. Otherwise there is a risk of frost damage.
Once hydrangeas have rooted well, they usually survive the winter in our latitudes without any problems. Frost is tolerated down to about minus ten degrees. Additional protection is not necessary. Nevertheless, winter damage is not uncommon. Late frosts can be particularly dangerous for the plants. However, most hydrangeas recover quickly from their cold shock and sprout again.
Why does the frost damage the hydrangeas?
Not all hydrangeas are fully hardy. Permafrost in harsh areas can cause frost damage.
The following species are generally considered to tolerate frost well:
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- Forest Hydrangeas
- Climbing Hydrangeas
- Japanese Hydrangeas
- Plate Hydrangeas
It becomes problematic for the hydrangea when the frost strikes again in late winter. The flower buds of the plants are created in summer. Late frosts damage the buds and the hobby gardener has to do without the abundance of flowers in the coming garden year.
Which hydrangeas are particularly endangered?
Peasant hydrangeas are particularly affected by frost damage. These are among the semi-shrubs. The ends of the shoots do not completely lignify in autumn. The frost can penetrate easily. In harsh winters, the damage isn't just limited to the non-lignified areas: the lignified branches are also damaged.
Tip: If the bark appears brown-black and dry, the branch is frozen.
Rarer fancier varieties that are less well adapted to our climate are particularly sensitive to frost. Here it is worth taking a look at the labels of the varieties. It should be noted there whether winter protection is necessary.
Oak leaf hydrangeas should be planted in a sheltered location and are considered sensitive to frost. Hydrangeas with two-tone leaves are also more likely to suffer frost damage.
Tip: Hydrangeas offered in hardware stores and discounters are adapted to our climate and are robust and winterproof.
Frost damage - what to do?
Hydrangeas are pruned in spring. The hobby gardenerremoves the old blooms over the new buds. If shoots are frozen, they are generously cut back down to the he althy wood. It will often be necessary to remove the shoot completely.
If the shoots are completely frozen, older farmer's hydrangeas may not bloom. The damaged plants can be cut back close to the ground. The buds are formed on the new wood. This ensures that the flowers will bloom in the coming summer.
Tip: Some cultivars will flower despite frost damage.
Only in rare cases do the plants die off completely and have to be replaced by new hydrangeas or other hardy plants in spring.
Preventing frost damage to hydrangeas
Select protected location
When planting, it should be considered that hydrangeas in rough locations are particularly damaged in late winter. A sheltered location is to be chosen. This assumes that the location is not only sheltered from the wind, but also that the sun does not fall on the plants.
This may sound like a paradox, since heat protects against frost damage. A warm location also results in early budding. The onset of late frost can then affect the plants all the more.
Attach winter protection
Frost damage can be prevented with suitable winter protection. It is particularly important to cover young plants with a layer of brushwood or leaves before winter. To ensure that the shoots are well protected, the entire plant can be wrapped in garden fleece.
A layer of mulch around the plant is like a warm blanket. If the location is less sheltered, it is advisable to create a layer of compost or garden soil about eight inches deep around the roots.
Be careful with winter protection!
On the one hand, it is important to protect sensitive or young hydrangeas. At the same time, care must be taken not to suffocate the plants with the protective measures. The hydrangea needs to be able to breathe under its winter shelter. Therefore, use air-permeable materials and never plastic bags. The impermeability to air sets a rotting process in motion and the plants are probably massively damaged after the winter.