Deutzia

Family Hydrangeaceae. Name: in honor of the mayor of Amsterdam Johann van Deitz.

Description: the genus contains about 50 species, distributed in East Asia, the Himalayas, and Mexico.

These are showy-flowering deciduous shrubs, spreading or erect in habit, from 0.5 to 4 meters tall.

Showy-flowering deciduous shrubs with opposite leaves and abundant white or pink scentless flowers gathered in terminal raceme-like inflorescences. They bloom on last year's shoots. They grow well on any soil types and are generally very undemanding in cultivation, if not for the almost annual freezing of the shoots on which the flower buds actually form. At -25°C partial freezing of branches is already observed, and at -30°C and below their death above the snow cover level is guaranteed. However, deutzias have a remarkable quality: even after severe freezing up to the snow cover, the shoots regrow and even flower in the same year. In our country, in cultivation, deutzias have become the most widespread. Location: light-loving, drought-tolerant.

Soil: prefer a nutritious, moderately moist soil. Composition: humus, peat-compost, sand (2:1:2), with added lime. If the soils are acidic, add 300 g of slaked lime or 200 g of wood ash per bush into the planting hole.

Planting: Distance between plants in a row 2.5 m, between rows - 2 m. It is better to place the bushes in open or slightly shaded locations away from midday sun. Planting depth 40 - 50 cm, root collar at ground level. The root system of deutzias consists of 1 - 2 large roots going down and a mass of fine fibrous roots. Thanks to the latter, deutzia tolerates transplanting well. Drainage: a layer of sand 10 - 15 cm at the bottom of the hole.

Care: to improve flowering, fertilize from time to time with liquid manure (1:10), 5 - б l per plant. Mineral fertilizer is applied immediately after pruning (Kemira-Universal 100 g/m²). Where plants suffer from early autumn frosts, fertilize only in spring and until the first half of summer so that plants have time to finish growth and prepare for winter. For spring digging per 1 sq. m apply: 300 g of slaked lime (air-slaked lime or dolomite flour), 10 - 20 g of potassium salt, 3 - 4 kg of well-rotted manure or compost.)

In hot dry summers water 2-3 times a month, 15 - 20 l per plant; in normal times watering is moderate and less frequent, 1-2 times with 8 - 10 l per plant.

Along with weed removal, loosen the soil to a depth of 20 - 25 cm. Mulch young plantings with peat to a depth of 5 cm. Thinning and rejuvenation as bushes age. Heavy pruning involves cutting back to a stump. To give the bush an attractive shape, cut off spent branches to the first strong new shoot or to the base. In early June cut off shoots frost-damaged in winter. Deutzias are not trimmed in hedges!

For winter, light covering with dry leaf litter, 10-20 cm thick, bending branches to the ground, earthing them up with soil or snow. Bending to the ground of young plants not higher than one meter is not difficult: such bushes bend easily. But particularly impressive are large plants around 2 meters high. In such deutzias the shoots are tubular-hollow and break easily, so bending and covering them with fir boughs and dry leaves is rather difficult. How to protect the plants from freezing? A. Milyaev from Voronezh suggests the following solution. In late autumn it is necessary to tightly bind the bushes with any breathable material, for example, synthetic material from empty sugar sacks. At the moment of covering in Voronezh deutzias usually have not yet dropped their foliage (in the Moscow region it falls). Therefore the leaves remaining on the branches serve as additional insulation. It is difficult to state unequivocally, but it can be assumed that in severe frosts deutzia shoots do not so much freeze as dry out. With this simple and not very difficult method of sheltering, it is possible to almost completely preserve the bushes from freezing even in winters with temperatures of -30°C. It is worth noting that A. Milyaev never recorded cases of plant rot either.

Pests and diseases: deutzia is resistant to diseases and many pests. Rarely the bumblebee-like weevil chews the leaves. Treatment with phthalophos at 0.15% concentration.

Propagation: by seeds, layers, root suckers, semi-hardwood and soft cuttings. Sowing is done in spring without preliminary seed treatment. It is sufficient when sowing to press the seeds firmly to the soil and not cover them. Seedlings will appear in about three weeks. Seed viability is retained for one to three years. Store seeds in tightly closed containers or sealed polyethylene bags in a cool place. To avoid overdrying of seeds and seedlings, sowing is better done in seedboxes.

Annual seedlings are sensitive to low temperatures and require mandatory covering. Given their low winter hardiness, pricking out is done in spring. Under favorable conditions seedlings will bloom in the third year. Good results are obtained with softwood cuttings. Cuttings are collected in the second half of June - first ten days of July. At air temperatures from 15 to 30°C and artificial fogging (spraying from nozzles) rooting rates are 90 - 100%. They can also be propagated by semi-ripe cuttings, layers and root suckers.

Uses: dwarf deutzias are used as borders; others in small groups near paths, for solitary plantings and underplanting of tree groups. Quite resistant in urban conditions. One of the most important conditions for successful cultivation is correct pruning after flowering. Overgrown bushes must be thinned. They grow quickly and under favorable conditions flower in the third year after sowing. The ornamental value of deutzia has long been recognized by practical gardening. Profuse and colorful flowering and the grace of the flowers give plantings exceptional beauty. It is no wonder that the outstanding explorer of Chinese flora E. H. Wilson placed deutzias on a par with roses, lilacs and hydrangeas.