Bases of young shoots were treated with the Ukorzeniacz B2, preparation stimulating adventitious roots development. Then piles of a mixture of white peat and hortisol were made around the shoots. The shoot growth was accompanied by increasing the height of piles. After one vegetative period the rooted layers were removed off from half of the piled plants, and after two vegetative periods – from the other plants. The quality of the rooted layers was estimated and in spring 1998 and 1999 new plants grew from them. On average 85.2% of Paeonia lactiflora Pall. shoots piled over one vegetative period, and 75% of those piled over two vegetative periods took roots. A higher rooting quality was recorded in two-year layers. Regardless of the piling period, new plants were developed from the all rooted layers in ‘Avelanche’, ‘Lady Dormouth’ and ‘Reine Hortense’ cultivars. These and other cultivars whose layers rooted in over 70% cases, i.e. ‘Baroness Schröder’, ‘La Rosi?re’, ‘Marechal McMahon’, ‘Monsieur Jules Elie’, ‘Profesor Wóycicki’, ‘Thér?se’ and ‘Ursynów’, can be propagated with vertical layers.

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