Nutritional requirements of Clematis vitalba L (old man’s beard)

Abstract The nutritional requirements of the naturalised vine, Clematis vitalba, were investigated in order to determine soil factors which might restrict its growth. Topsoil samples (0–10 cm), collected from 19 sites where C. vitalba has naturally established in New Zealand, had moderately acid to near neutral pH values, high to very high percentage base saturation, and medium to very high concentrations of the exchangeable cations Ca, Mg, and K, but tended to have low plant-available P and phosphate-extractable sulphate concentrations. Extractable-Al concentrations were very low. Profile descriptions at these sites showed that almost all soils were being or had been rejuvenated by alluvium, colluvium, or tephra. The soils had few physical impediments to root growth, so plants were readily able to exploit the soils and their nutrients. In a glasshouse experiment, growth of C. vitalba increased with increasing rate of lime (CaCO3) and with increasing rate of applied P. Greatest growth in these conditions ...