Influence of the amount of water on the growth of one species and four hybrids of Paulownia in the first year of cultivation in Central Europe

<br>A lack or, conversely, an excess of water during the first growing seasons can bring about a slowdown in the growth of plants, their stagnation or even death. The necessary amount of water is not known for most hybrids of Paulownia. Therefore, one species and four hybrids were subjected to three regimes of watering to find out their impacts on plant height, radial growth, the amount of leaf biomass and leaf area. We planted 30 plants of each species/hybrid into plant pots under a shelter. At the end of the growing season, we measured the above-mentioned parameters. Our results showed that: (<i>i</i>) generally, amean precipitation of50 mm per month inthe growing season ('per month') seems tobeinsufficient for optimal growth ofPaulownia plants inthe first years after planting; (<i>ii</i>) each species/hybrid reacts differently tothe amount ofwater – P. Shan Tong grows better with 100 mm per month, <i>P. tomentosa</i> with 150 mm (and more) per month and the growth parameters ofthe others did not change (and remained low) with different amounts ofwater (P. Hybrid 9502, P. Bellissia^® and P. Clon <i>invitro</i> 112^®).