Enciclopedia Cornales Hydrangeaceae Hydrangeoideae Hydrangea

Hydrangeaceae

Hydrangea

Hortensia

Regno	Plantae
Sottoregno	Tracheobionta
Superdivisione	Spermatophyta
Divisione	Magnoliophyta
Classe	Magnoliopsida
Ordine	Cornales
Famiglia	Hydrangeaceae
Sottofamiglia	Hydrangeoideae
Genere	Hydrangea

Luce

Medium high

Acqua

Medium high

Specie

Hydrangea, commonly referred to as Hortensia or Hydrangea, is a captivating genus of flowering plants known for their stunning and diverse blooms. The genus includes around 70-75 species, each boasting unique flower shapes, sizes, and colors. Hydrangea plants are prized for their ornamental value and are popular both as garden shrubs and potted plants.

Habitat naturale

Hydrangea species originate from temperate regions of Asia and the Americas. They thrive in a variety of environments, often found in woodlands, riverbanks, and mountainous areas. The natural habitat of Hydrangea plants is characterized by moderate to high humidity, mild temperatures, and rich, well-draining soil.

Storia e cultura

Hydrangea plants have a rich cultural history in their native regions. In many cultures, they symbolize gratitude, grace, and abundance. Hydrangeas have been cultivated for centuries and are often used in traditional gardens and floral arrangements. They are especially significant in Japanese culture, where they are celebrated in festivals and used in tea ceremonies.

Utilizzi

In modern times, Hydrangea plants are primarily grown for their ornamental value. Their vibrant and abundant flowers make them popular choices for garden landscapes and floral displays. The wide variety of species and cultivars available allows for diverse aesthetic applications, from the classic Hydrangea macrophylla to the more unique Hydrangea quercifolia with its oak-like leaves.

Conservazione

While many Hydrangea species are commonly cultivated, some are considered rare or endangered in their natural habitats due to habitat destruction and climate change. Conservation efforts are important to preserve the genetic diversity and ecological roles of these plants in their native regions.

Specie e varietà (7)

Hydrangea anomala subsp. petiolaris

Hydrangea arborescens

Hydrangea macrophylla

Hydrangea paniculata

Hydrangea petiolaris

Hydrangea quercifolia

Hydrangea serrata

Guida alla cura

Luce

Indoors, place in the brightest spot available — near a large window with several hours of direct morning sun. Hydrangeas are primarily outdoor plants and require significant light to sustain their blooms. Insufficient light causes rapid leaf drop and flower fade. After blooming, move outdoors or to a sheltered cool spot for summer recovery.

Acqua

Hydrangea is one of the thirstiest houseplants. Keep the soil consistently and thoroughly moist — check daily during flowering, as pots can dry out within 24 hours. Wilting is a stress signal that reduces flower life significantly. Use room-temperature water and ensure perfect drainage. After blooming, water less frequently but do not let it dry out.

Substrato

Use a moisture-retentive, fertile potting mix with some added perlite for drainage. Slightly acidic pH (5.5–6.5) is ideal. Soil pH affects flower colour in H. macrophylla: acidic soil (pH 4.5–5.5) produces blue flowers; neutral to alkaline soil (pH 6.5+) produces pink flowers. Aluminium sulphate acidifies; garden lime alkalinises.

Temperatura e umidità

Indoor flowering temperature 12–18 °C is ideal to prolong blooms. Cooler rooms significantly extend the flowering period. After blooming, plants need a cold dormancy period (4–7 °C) for 6–8 weeks in autumn/winter to set buds for next year — an unheated garage or shed works well.

Concimazione

After blooming, feed monthly through summer with an ericaceous (acidic) liquid fertilizer. Do not feed during the dormancy period. Resume feeding in early spring as growth restarts.

Potatura

After blooming indoors, move the plant outdoors to a sheltered, lightly shaded spot. Deadhead spent flowers. Prune lightly in late summer, removing only dead stems (most Hydrangeas flower on old wood — heavy pruning removes next year's buds). Repot every 2 years.

Propagazione

Talea

The most common method for propagating Hydrangea is by taking cuttings. This involves cutting a healthy stem from the parent plant and rooting it in soil.

Cut a 4-6 inch long stem from a healthy Hydrangea plant, just below a leaf node.

Remove the lower leaves and dip the cut end in rooting hormone.

Plant the cutting in a pot with well-draining potting mix, water thoroughly, and cover with a plastic bag to maintain humidity.

Place in a bright, indirect light location and keep the soil moist until roots develop.

Propaggine

Another method for propagating Hydrangea is by layering, where a low branch is bent to the ground and covered with soil to encourage rooting.

Select a healthy, flexible branch near the base of the plant.

Bury a section of the branch 1-2 inches deep in the soil, leaving the tip exposed.

Secure the buried section with a stone or a U-shaped pin.

Water regularly and check for root development after a few months.

Once rooted, cut the new plant from the parent and transplant it to a desired location.

Domande frequenti

My Hydrangea wilted even though I just watered it — what's wrong?

Wilting immediately after watering usually means root rot from previous overwatering, or the pot is so dry the water ran straight through without absorbing. Submerge the pot in a bucket of water for 30 minutes to fully re-hydrate. If the roots are brown and mushy, root rot has set in.

How do I get my Hydrangea to rebloom next year?

After blooming, move outdoors for summer. In autumn, allow it to go dormant with a 6–8 week cold period (4–7 °C) — an unheated garage works well. Resume normal watering and bring indoors to a bright cool room in early spring. New buds will form and it should rebloom.

How do I change my Hydrangea flower colour to blue?

Blue colour in H. macrophylla requires acidic soil (pH 4.5–5.5) and the presence of aluminium. Apply aluminium sulphate to the soil mix and use ericaceous compost. This only works on pink varieties — white varieties cannot turn blue.

Proponi una modifica