Tree hydrangea «Grandiflora»

Synonyms: 'Hills-of-Snow'

Tree hydrangea Grandiflora – a cultivar of tree hydrangea. It was discovered in the wild in 1907 in the state of Ohio (USA). The cultivar received the English Horticultural Society's AGM (Award of Garden Merit) in 1993. Lives up to 40 years.

It is a deciduous ornamental shrub 1.5-2 m in height and 1.5-3 m in diameter. Grows rapidly, annual growth reaching up to 25 cm. The crown is spherical, dense; branches often droop to the ground under the weight of the inflorescences.

Leaves large, bright green, 16-30 cm in length, ovate in shape, 6-10 cm in length, in autumn – green.

Flowers – flat corymbose inflorescences up to 20 cm in diameter, irregular asymmetric shape, consisting of numerous small sterile florets up to 3 cm in diameter, initially olive-green, later – white, and before fading become creamy-white. Blooms very abundantly from June to September. Dry inflorescences persist until spring.

Hardiness zone: 3-9 (-39°C).

Location: Heat-loving, demanding of moisture. Grows well in semi-shaded locations, but more abundant flowering is observed only in full sun. Can tolerate short periods of drought. Requires a site protected from wind.

Soil: does not tolerate lime. Grows well on humus-rich, alluvial and red soils with moderate moisture in areas with high annual precipitation. On podzolized and clay soils that dry out in summer, it significantly lags in growth and suffers from drought. Can tolerate alkaline soil.

Planting: optimal age for planting – 2-3 years. Planting is best carried out 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 at the bottom of the hole in the form of gravel or crushed brick in a layer of 5-10 cm. A layer of fertile soil 10-15 cm is placed over the drainage. Spread the roots across the entire area of the hole and place the root collar at ground level. Water consumption 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 bush 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 the strength of shoots you can water along the crown and at the root with a weak solution of potassium permanganate. Fertilization with manure or mineral fertilizers is carried out at the beginning of growth, during bud formation, and also 1-2 times during the summer.

Pruning: Pruning is done annually at the end of March - beginning of April, a full cutback to the base, starting from 4 years of age. Cut shoots can be used as cuttings.

Propagation: easily propagated by green cuttings and division of the bush. Rooting rate of cuttings 100% without treatment. Also propagates well by layering. Cuttings are best prepared during the flowering period; for this, cut the tips of the current year's shoots. In early April dig a hole 60-70 cm deep and 50 cm in diameter. Place the cutting into it and fill with a pre-prepared mixture. Soil mixture: humus, chernozem, peat and sand in ratio 2:2:1:1. Also add 20 g of urea, 30 g of potassium sulfate and 30 g of superphosphate. Repeat similar fertilization after 2 years.

Pests: aphids (pelargonium, greenhouse, pea), greenhouse thrips, spittlebug, spider mite, green tree bug, strawberry bug, meadow bug, shiny pale leaf beetle, nettle leaf weevil, cutworms (caterpillars of noctuid moths), golden chafer, woolly aphid, marsh crane fly, earwig, gall nematode.

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

Use: used in solitary and group plantings, for attractive freely growing hedges, in ornamental groups, in garden and park compositions.