Evaluation of five introductions of the subtropical grass Hemarthria altissima at a frost-prone site in Northland

Abstract

Hemarthria altissima accessions ‘Bigalta’, ‘Floralta’, PI 349753, PI 364884, and PI 364891 were planted on a valley flat near Whangarei in 1982 using stem pieces as propagules and irrigation to promote establishment. Under weedy conditions the first three established in 15 months, whereas the others had to be replanted with turfs to obtain satisfactory establishment in 2 years. In 1984–85 there were no damaging frosts and all lines had high annual dry matter (DM) yields of up to 21 and 16 t/ha under mowing heights of 3 and 8 cm respectively. Under the same treatments ‘Grasslands Wana’ cocksfoot produced 16 and 15 t DM/ha. Frosts to -5.5°C in winter 1986 severely damaged ‘Bigalta’ and PI 349753 irrespective of mowing height and their 1986–87 yields were reduced to 4–7 t DM/ha. These frosts had only minor effects on PI 364884 and PI 364891 and their yields remained high. ‘Floralta’ rated intermediate in response to 1986 frosts. In winter 1987 ‘Bigalta’, PI 349753,and ‘Floralta’ were eliminated by frosts, whereas PI 364884 and PI 364891 were severely damaged by frosts under 3 cm mowing but little affected under 8 cm mowing. Although none of the five hemarthrias was completely winter-hardy, the results suggested that PI 364884 and PI 364891 could be grown at frost-prone sites if close grazing was avoided.

Keywords:

• mowing trial
• winter hardiness
• summer production
• frost damage
• plant establishment
• vegetative propagation
• Hemarthria altissima
• limpograss