We clarify: Are hydrangeas hardy?
- Hardy and frost hardy
- The hardiness of the hydrangea species
- The winter hardiness of the cultivars
- The hardiness of the hydrangea in the tub
Hydrangeas are hardy, in their home anyway; At your place of residence, it depends only on the species, variety, breeding goal, rearing, hardiness zone, climate and microclimate - and how you classify this, reveals the article. Whether hydrangeas are hardy depends on many different factors, here "Roadmap for hardy hydrangea", step by step:
Hardy and frost hardy
Winter hardy is the term for cold tolerance of a plant that grows in alien climate and in foreign soil. Winter hardy is not the same as frost hardy, the frost hardiness says something about how insensitive a plant species is in its natural environment against low temperatures.1 out of 5
The hardiness depends on the chemical composition of the plant juices and the construction of the plant, and on the supply of nutrients. Above all, high potassium is recommended for the last fertilization, because potassium regulates the water balance in the cells and thus has a favorable influence on the frost hardness. Hardy are almost all perennial plant species that grow in latitudes above about 40 °, so almost all perennial native plant species, Germany is between the 47th and 55th parallel.
The terms come together in that a plant that is frost hardy in their homeland is often hardy in another part of the world. The prerequisite is that there is frost at all in the homeland of this plant, because of this the hardiness of many hydrangeas fails: hydrangea species have developed mostly in temperate warm to tropical warm temperate areas of East Asia, a few come from (warm) Southeast Asia, South America, Azores, and only a few from the German climate closer North America.
If a plant is hardy in their homeland, it is not winter hardy anywhere in the world. Because the climate in their homeland can still differ significantly from the climate of the new home, a typically rainy winter as with us can prepare a plant from rather dry areas cold-independent problems.
The hardiness of the hydrangea species
Whether or not a hydrangea is hardy or hardy will depend on the species or its origin. And how much the climate in this homeland of hydrangeas resembles ours, not only in terms of the cold.
In the article "Hibernate Hydrangeas" you will find a list of the most frequently sold species and the winter hardiness that is assigned to them.
All hydrangeas, which are unanimously classified in USDA hardiness zone 5 and colder, are likely to have little problems in German winter even with continuous rain and other unfamiliar weather phenomena, which are not many of the species available in our country, eg. Hydrangea quercifolia, Hydrangea petiolaris, Hydrangea arborescens, Hydrangea paniculata and Hydrangea Sargentiana.
All hydrangeas listed for USDA winter hardiness zone 6 to 7 are hardy in most parts of Germany - if they are strong and adult. Hydrangea aspera, Hydrangea involucrata, Hydrangea macrophylla and Hydrangea villosa.
All hydrangeas not enduring USDA hardiness zone 7 or 8, eg. B. the giant leaf hydrangeas, Hydrangea aspera, Macrophylla ', could come in a few particularly warm corners of Germany (on the coast, to Essen, Cologne, Koblenz, Mainz, Ludwigshafen) well over the winter, elsewhere it will be tight ...
The winter hardiness of the cultivars
In the vast majority of cases you do not buy the original type of a particular hydrangea, but a variety of this species.
Breeding can have a positive effect on winter hardiness, but can also make a hydrangea more sensitive to cold, depending on what the breeder had in mind: only large flowers for sale in warm areas or winter hardier plants than the original for many places in the world. How much time he has left for the creation of this breeding result and with what care / knowledge he has taken overall, of course, also plays a role.
There are some cultivars that are known for good winter hardiness, but: It also depends on how a hydrangea was raised, hardened and treated in the course of the sale. As a commodity for the next special offer in a warm greenhouse, from there into a small container with cheap substrate and in the warehouse of a wholesale, with not just plant-appropriate environment and supply. Or as outdoor rearing in a nursery that is in a temperate, similar to your location climate, in good soil and with good root care, carefully hardened - it no longer needs to be explained who can endure more.
The hardiness of the hydrangea in the tub
In the previous text it was about the decision whether a hydrangea is so hardy that it can ever be freely planted in the garden, this hydrangea will be a young plant in many places in Germany, a more or less long time "living in the tub ".
If you want to buy a hydrangea that will last for a lifetime in a bucket, you have to pay attention to the winter hardiness exactly the same, if the hydrangea should stand on a terrace not further shielded from the garden and you do not have a frost-free room (around 5 ° C) have available at the bucket to overwinter.
Balcony or terrace but can also have up to 1, 2 zones warmer microclimate: In the middle of the city, on the south side, totally installed between heated rooms, the tenant underneath is a very old lady and lives at 26 ° C average temperature ... there can You already try it with one or the other hydrangea with tropical homeland ... z. Hydrangea seamannii, which, according to some sources, should withstand USDA hardiness zone 8a, down to -12.2 ° C, others only down to -5 ° C.