climbing hydrangea (Hydrangea petiolaris)
The climbing hydrangea (Hydrangea petiolaris) from the Hydrangeaceae family, grows on walls, facades, pergolas and fences and is an ornament in the garden with its fine white inflorescences. It originates from the forests of Japan, Taiwan and Korea. The decorative climbing shrub is hardy and easy to care for.
The shoots of the climbing hydrangea (Hydrangea petiolaris) form adhesive roots on the side facing away from the light, which then develop into thicker branches. The bark is reddish brown and peels off older branches. Climbing hortensias can reach a height of up to 15 metres on trellises, walls and walls, but initially grow rather slowly. Without climbing help, the climbing hortensia grows into a hemispherical and wide shrub and can also serve as a ground cover.
The leaves of the climbing hortensia are shiny green, ovoid to rounded and about ten centimeters long. They sit on long petioles and turn bright yellow in autumn. With some varieties they remain green in mild winters and adhere to the shoots until next spring.
The sweet-smelling flowers appear from May to July. They are flat and arranged in inflorescences up to 25 centimeters wide. The so-called umbrella panicles have a wreath of sterile white show flowers on the outside. The inner flowers are fertile and have no petals. Climbing hortensias bloom only after about five years of standing.
Location and soil
The climbing hortensia thrives in semi-shade to shade in cool and humid locations on permeable and humus-rich soils. The plants do not tolerate calcareous soil and are sensitive to soil compaction.
Planting and care
Climbing hortensias require a slightly acidic to acidic soil, so you should put some rhododendron soil in the planting hole. The most favourable planting period is March to mid-May. The diameter of the planting hole should be about twice the size of the root ball. Loosen it a little and water it well after planting. In addition, you should immerse dry pot balls in a bucket of water for a few minutes before planting. A mulch layer around the climbing horticulture keeps the soil evenly moist, and the shoots of the plant find support on bare walls similar to ivy, as long as they are not too smooth. This is possible thanks to special adhesive roots. However, young plants can still benefit from a climbing aid to guide the shoots upwards and support growth. You should attach the branches to a wall or fence with wires. Climbing hortensias require sufficient water and should be kept evenly moist, but waterlogging must be avoided. In spring, you can ripen the leaves, enrich them with horn semolina, and spread the plant with rhododendron fertilizer.
Climbing hortensias are compatible with pruning, but as a rule pruning is not necessary if the plants have enough space to spread. If necessary, you can shorten the shoots of young climbing hortensias by about a third directly after planting to stimulate branching. Older plants can also be pruned back into perennial wood without any problems. The ideal period for cutting is February and March.
Climbing hortensias are suitable as decorative climbing plants on walls, pergolas and fences. Then their inflorescences and leaf ornaments come into their own. Together with Clematis the climbing hortensias create a beautiful picture on a wall or facade.
Semiola’ blooms white and is a new variety that keeps its green foliage in mild winters. In spring it shows a copper-red bud and grows up to three metres high. It can also be used without climbing aid and can serve as an attractive ground cover. Silver Lining’ is also often winter green. The variety has fine, white-green variegated leaves and is also suitable as a pot plant on the balcony. ‘Miranda’ flowers creamy white with large flowers and bears yellow-green leaves.
Climbing hortensias can easily be multiplied from spring to early summer by depositing lateral shoots close to the ground. Remove the leaves from the shoots in the middle section and make a so-called wound cut by lifting off a narrow strip of bark with the pocket knife on the underside. Then dig the middle shoot segment lightly into the humus-rich soil and fix it if necessary and keep the soil evenly moist. In the course of the season, the offshoot takes root and can then be separated from the mother plant and transplanted in autumn or spring.
If you want a larger number of offspring, you can also use climbing hortensias from cuttings. The young, slightly woody and flowerless shoots are best suited for this in June and July. The cultivation method otherwise corresponds to the propagation of cuttings of farmer hydrangeas. Alternatively, it is also possible in winter to cultivate from unrooted cuttings – the so-called cuttings.
Diseases and pests
Climbing hortensias are robust climbing plants that are hardly affected by diseases or pests. Sometimes chlorosis can occur. Then the leaves turn yellow and are traversed by green veins. A dose of rhododendron soil or peat can prevent this. Occasionally there are also downy and downy mildew.
I am Don Burke, one of the authors at My Garden Guide. I am a horticulturist that cultivates, grows, and cares for plants, ranging from shrubs and fruits to flowers. I do it in my own garden and in my nursery. I show you how to take care of your garden and how to perform garden landscaping in an easy way, step by step.I am originally from Sydney and I wrote in local magazines. Later on, I have decided, more than two decades ago, to create my own blog. My area of specialization is related to orchid care, succulent care, and the study of the substrate and the soil. Therefore, you will see many articles dedicated to these disciplines. I also provide advice about how to improve the landscape design of your garden.