Panicled hydrangea 'Unique'

Panicled hydrangea 'Unique' (Hydrangea paniculata Unique) – a cultivar of panicled hydrangea. The cultivar was obtained by Robert and Jelena De Belder (Jelena and Robert De Belder) at the Hemelrijk estate (Antwerp, Belgium) in the 1950s. It received the Royal Horticultural Society AGM (Award of Garden Merit) in 1993.

It is a deciduous shrub 1.5-2 m in height and up to 3 (5) m in width. It grows rapidly, with an annual increase of about 20 cm. Shoots are stiff, strong, erect, not thick, brown-red in color, pubescent, later becoming glabrous. Bark is brown and peeling. The root system is superficial, well-branched with a large number of fine roots.

Leaves are ovate, green, rough, firm, with a serrated margin, arranged oppositely, less often in whorls of three. They reach 10-14 cm in length and 5-8 cm in width. Autumn coloration is not pronounced.

Flowers from late July until the end of September. Inflorescences are sterile, gathered into broad conical panicles up to 30 cm long, borne at the tips of shoots. Flowers are milky-white when opening, acquiring pink shades as they fade.

Does not fruit.

Hardiness zone: 4 (-29°C).

Location: heat-loving; shaded sites are best for planting. Needs protection from strong and cold winds. Drought-tolerant but prefers moist places. Not recommended to plant near fruit trees. Tolerates urban conditions well.

Soil: grows well on fertile, slightly acidic to acidic soil; does not tolerate calcareous soils. Prefers moist, well-drained soils without waterlogging.

Planting: optimal age for planting is 2-3 years. Planting is best done in spring or autumn. Planting hole size on light cultivated soils - 40x40x50 cm, on loamy cultivated soils - 50x50x60 cm, on heavy clay soils - 60x60x70 cm. It is recommended to place drainage such as gravel or crushed brick at the bottom of the hole in a layer of 5-10 cm. Over the drainage, place fertile soil in a layer of 10-15 cm. Spread the roots evenly over the whole area of the hole, and place the root collar at soil level. Watering after planting per plant: on sandy loam 20-25 L, medium loam 15-20 L, heavy loam 10-15 L. In dry and windy weather it is recommended to spray the plant immediately after planting.

Care: it is recommended to loosen the soil around the shrub at least twice a year to a depth of up to 5 cm. Watering should be done at least 5 times per season. To increase shoot strength you can water along the canopy and at the root with a weak solution of potassium permanganate. Manure or mineral fertilizers are applied at the beginning of growth, during bud formation, and also 1-2 times during the summer. In winter it requires covering with fir boughs or dry leaves.

Pruning: tolerates pruning well. For abundant flowering it is recommended in spring (after bud swelling) to prune diseased shoots; in older plants prune shoots annually to 2/3 of their length.

Propagation: mainly by cuttings. Cuttings can be taken only in the first decade of June; choose a cutting with 5-6 nodes, remove the leaves from the two lower nodes, then bury the cutting in loose, moist soil to two nodes. It is recommended to add some sand to the soil. The remaining leaves should be cut back by 2/3. After that cover the cutting with a 2- or 3-liter jar. Cuttings should be placed in the shade and the soil kept constantly moist.

Pests: aphids (pelargonium, greenhouse, bean), greenhouse thrips, spittlebug (froghopper), spider mite, green tree bug, berry bug, meadow bug, pale shining leaf beetle, nettle leaf weevil, cutworms (caterpillars of nocturnal moths), golden chafer, ("olenka" hairy moth/larva), marsh crane fly, earwig, gall nematode.

Diseases: tracheomycosis wilting, white sclerotial rot, gray mold, common (European) canker, tubercular bark necrosis, powdery mildew, Phyllosticta, Septoria, ring and Ascochyta leaf spot, chlorosis.

Use: Used in single and group plantings, as an accent in tree-and-shrub compositions. Looks impressive in parks and urban gardens, on flowerbeds and in urban landscape compositions. Combines well with other hydrangea cultivars.