Hydrangeas are the stars of every cottage garden. The robust garden plants survive many a cold winter. Sometimes, however, hydrangeas can be frozen in the spring. All measures for prevention and help for this below.

In a nutshell

  • A hydrangea is one of the more robust garden plants
  • Late frosts can be particularly dangerous
  • Frozen shoots are light brown to dark brown and dry
  • No pruning should be done in the fall
  • Winter protection can prevent frostbite

Hydrangeas very hardy

Hydrangeas (Hydrangea) are usually among the more robust garden plants. They are conditionally hardy and survive many a frost period. However, they are very sensitive to late frosts that occur in spring after new growth. Hydrangeas are particularly susceptible, as they already have the flowers for the coming garden season in the previous year. It can quickly happen that the tender buds fall victim to the frost. In other words, they're frozen. These include peasant hydrangeas (Hydrangea macrophylla) and also plate hydrangeas (Hydrangea serrata). Frost damage to hydrangeas is recognizable:

  • on light brown to dark brown shoots
  • Shoot often dry

Sometimes the perennials appear frozen after winter, but they are not. To be really sure whether the shoots are dead, simply scratch the bark lightly with your thumbnail. If it comes off easily and then a green, juicy tissue appears underneath, there is still life in the shoots. On the other hand, a slightly yellowish-green discoloration below the last pair of eyes indicates that the shoot has dried up and is dead.

Notice: Shade-loving hydrangeas are less susceptible to frost damage in winter than hydrangeas that prefer a sunny location.

measures in spring

Normally, in the spring of a hydrangea, only the withered, old flowers are cut off directly above the top pair of eyes. Now, with frozen shoots, only a complete pruning usually helps.
In addition:

  • Cut back to the first living pair of buds
  • if the damage is severe, remove the drive completely
  • don't cut back too early
  • best time at the end of February / beginning of March
  • next to it, thin out hydrangeas well

Sometimes it can also happen that a hydrangea is damaged more severely in very cold winters with severe frosts. However, this is relatively rare. In this case, a complete pruning should be done down to the ground. With a lot of luck and patience, the plant will sprout again. However, there are differences in the individual species and varieties with regard to the flowering splendor to be expected after pruning.

Hydrangea with flower plant in the previous year

  • These include plate hydrangea (Hydrangea serrata), farmer's hydrangea (H. macrophylla), velvet hydrangea (H. sargentiana) and climbing hydrangea (H. petiolaris)
  • the harder the pruning, the lower the blooms
  • in the case of radical pruning, there will be no flowering at all that year

Hydrangea with flowers on the "new" wood

  • These include snowball hydrangea (Hydrangea arborescens) and panicle hydrangea (H. paniculata)
  • Pruning has no effect on flowering
  • Buds are always planted in the same year
  • however, there must be a pair of eyes per shoot

However, if there is no longer a living shoot with a pair of buds, then it is advisable to dig up the hydrangea bush and replace it with a new one.

Notice: When buying, you should already pay attention to the winter hardiness of the corresponding hydrangea, so as not to be nasty surprised in the coming spring. The plant label provides information about the respective winter hardiness. In addition, professional advice is advisable.

Late frosts particularly dangerous

Frosts that occur in April/May, especially after new growth, can severely damage the young and still soft shoots. If the temperature falls well below -5 °C, then it is hardly possible to save this year's blooms. However, if only the young leaves are affected, they are simply removed. They are subsequently replaced by new ones. It is not necessary to cut back the shoots. However, the situation is different when the shoot tips hang down. Then you have to grab the scissors and shorten the affected shoot to the next living pair of eyes. A light winter protection is recommended during this time.

prevent frost damage

In order to avoid frost damage to hydrangeas in advance during the cold season, certain measures should be taken. It starts with the choice of location. This can already prevent damage. Furthermore, this includes:

  • Protection from cold east winds
  • Avoid strong sunlight, especially in winter
  • Sun favors early sprouting
  • late frosts then cause greater damage
  • Do not cut off wilted flower heads in autumn
  • provide protection for underlying buds
  • no pruning in autumn
  • remove dead wood, source of rot, fungi and pathogens
  • Shorten protruding shoots, danger of snow breakage
  • Discontinue nitrogen fertilization from July
  • Organic fertilizer can be added up to August
  • optimal administration of potassium-rich fertilizers such as Patentkali
  • thereby maturation and lignification of the shoots until winter
  • Stop fertilizing completely from September
  • water sufficiently in autumn
  • Avoid waterlogging
  • with root damage plant more susceptible to frost damage

Tip: Administration of potassium-rich fertilizer until September increases the frost hardiness of the plants. The nutrients strengthen the cell walls and at the same time lower the freezing point of the existing cell water. It is also excellently suitable as an autumn fertilization in addition to Patentkali comfrey manure.

Apply suitable winter protection

Although hydrangeas are relatively hardy, it is advisable to apply additional winter protection, especially in harsh areas. Such winter protection is particularly important for young plants that were only planted in the spring of the same year. These are not rooted deeply enough during the short time and frost damage can occur more quickly here. Various protective measures should be taken before winter sets in:

  • Mulch root slices
  • in addition application of 10 cm high layer of leaves
  • additionally cover them with fir branches
  • Pile up the root neck 10 to 20 cm high
  • suitable for garden or compost soil
  • Cover shoots with breathable winter fleece
  • alternatively place wire mesh loosely over shoots
  • then cover with pine sticks
  • Another alternative: Twigs stuck around the plant
  • Hydrangea must be able to breathe
  • After pruning, apply winter protection again if there is a risk of ground frost
  • Completely remove winter protection by mid-May at the latest
  • otherwise fungal infestation is favored by rising temperatures

Tip: Do not use foils or other airtight materials. Underneath, condensation forms and it quickly rots.

Winter protection for potted plants

Of course, a hydrangea in a tub also needs adequate winter protection during the cold season. Otherwise it can quickly happen that the shoots or even the entire plant freezes in spring. The following precautions should be taken:

  • Installation of buckets in a wind-protected place
  • Place bucket on a frost-proof surface
  • suitable wooden board or styrofoam
  • Cover the root disc with leaves, fir branches on top
  • Cover the bucket with bubble wrap, coconut mats or a jute sack
  • Cover shoots with special winter fleece
  • It is better to winter pots with a diameter of less than 35 cm frost-free indoors
  • temperatures between 3 and 5 °C
  • cool temperatures favor flowering

Notice: Not only can frost damage a hydrangea, drought stress in winter has even worse effects on the plant. Sunshine, frost with low temperatures and, of course, a lack of snow cover can quickly lead to the root ball drying out. It is therefore advisable to water the plant on frost-free days.

frequently asked Questions

Which hydrangea varieties are particularly frost-resistant?

When choosing, you should first consider varieties that thrive particularly well in the shade. They are definitely hardier than a sun-loving hydrangea. In addition, the trade offers varieties that are well tolerated by frost. These include:
peasant hydrangea
garden hydrangea
japanese hydrangea
forest hydrangea
climbing hydrangea and
plate hydrangea .
The plant labels provide information about this. Professional advice is of course even better.

How is a blue coloring of the flower heads achieved?

A prerequisite for a blue color is an acidic soil. The pH should be below 4.5. However, normal garden soils do not have this value. Therefore, before planting a hydrangea, the garden soil should be replaced with hydrangea or rhododendron soil. In addition, aluminum must be added to the irrigation water regularly. Special hydrangea blue or alternatively potash alum are commercially available. Please only use according to package instructions. The discoloration lasts for a long time, up to two years.

What must be considered when planting?

It should be noted that there are hydrangea varieties for sunny (panicle hydrangea) and shady locations (including farmer's hydrangea). Furthermore, these perennials love deep, nutritious, humus-rich and loose soil. This should be able to store water well, since hydrangea means "water slurper", which in turn provides information about the water requirements of the plants. It's relatively high. A special hydrangea or rhododendron soil is well suited for planting. In addition, it must be noted that the pH value of the soil must be in the acidic range.

Category:

Garden plants