EFFECT OF THE CUTTING LENGTH AND PROPAGATION PERIOD ON THREE THUJA OCCIDENTALIS VARIETIES

Abstract

Thuja occidentalis L. is originated from Eastern North America and it is cultivated in Europe as an ornamental tree. Thuja can be multiplicated generatively and vegetatively, however nurseries are propagating them by vegetative method because in this way the plants inherit the genetics from the mother plants. Furthermore, it is a faster method. Tree highly used Thuja occidentalis varieties: `Europa Gold` (TOE), `Smaragd` (TOS), and `Danica` (TOD) were selected for the research and were subjected to two different propagation periods (May and July). There were selected 5–10 cm, 10–20 cm, and 20–25 cm length stem cuttings. Our data showed different results at the selected varieties: at TOE, the 20–25 cm length cuttings reported a higher rooting at the July propagation period; at TOS were determined that the 10–20 cm cuttings and the May propagation period obtained the highest rooting percentage; in the case of the TOD an increase in rooting percentage was observed at the cuttings propagated in May, moreover the 5–10 cm length. It can be concluded that propagation time and stem cutting length could be an important factor, however is a variety-dependent process.