Hydrangea arborescens 'Annabelle'

Hydrangea arborescens 'Annabelle' (Hydrangea arborescens 'Annabelle') – an old, yet still one of the most popular cultivars of smooth hydrangea. The cultivar was discovered in 1746 in the village of Anna (Ohio, USA); from there it went to the «Gulf Stream» nursery and spread around the world.

It is an ornamental deciduous shrub with a dome-shaped, loose and spreading crown. It reaches 1–1.5 m in height and up to 3 m in diameter. It grows quickly, up to 15 cm per year. Shoots are sparsely pubescent, later glabrous, gray-brown.

Leaves are large, petiolate, ovate with serrated margins, glossy, light green, turning yellowish-green in autumn; they can reach up to 30 cm in length.

Flowers bloom abundantly and annually from late June to October. Flowers are gathered into large spherical inflorescences, 15–25 cm in diameter, greenish at first, later becoming white and staying turgid for a long time.

Hardiness zone: 3-9 (-39°С).

Location: Heat-loving, requires moisture. Grows well in partially shaded places, but more abundant flowering is observed in full sun. Can tolerate short droughts. Needs a sheltered location protected from wind.

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

Planting: the optimal planting age 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 on the bottom of the hole in a layer of 5–10 cm. A layer of fertile soil 10–15 cm is placed on top of the drainage. Spread the roots evenly across the hole and position the root collar at soil 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: 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 during the season. To increase stem strength, water along the crown and at the root with a weak solution of potassium permanganate. Fertilize with manure or mineral fertilizers at the beginning of growth, during bud formation, and also 1–2 times during the summer period.

Pruning: Perform annual pruning at the end of March–early April, a full pruning down to the base, starting from the age of 4 years. Cut shoots can be used as cuttings.

Propagation: easily propagated by softwood cuttings and by division. Rooting of cuttings is 100% without treatment. Propagates well by layering. Cuttings are best taken during flowering; 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 in it and cover with a prepared mixture. Soil mixture: humus, chernozem, peat and sand in a ratio of 2:2:1:1. Also add 20 g of urea, 30 g of potassium sulfate and 30 g of superphosphate. A similar feeding is repeated after 2 years.

Pests: aphids (pelargonium, greenhouse, pea), greenhouse thrips, salivary psyllid, spider mite, green tree bug, strawberry bug, meadow bug, shiny tan leaf beetle, nettle leaf weevil, owlet moths (caterpillars of noctuid moths), golden chafer, hairy bronze chafer, marsh crane fly, earwig, gall nematode.

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

Uses: looks spectacular in solitary and group plantings. Most effective in a solitary planting where the shrub can be viewed from all sides. Used to create edges in woody-shrub compositions and to form informal living hedges. Recommended for cultivation in home gardens.