(229) Fertility Affects Cutting Production and Quality of Rooted Cuttings of Iva imbricata

Abstract

Seacost Marshelder (Iva imbricata Walter [Asteraceae]), a dominant Atlantic and Gulf region seashore plant, is a broad-leaved plant with a potential for building and stabilizing foredunes in the South Atlantic coast of the United States, and is recognized as an important food for beach mice. Two experiments were conducted where nursery liners were potted as stock plants and produced at four rates of fertility using Osmocote Plus (15N:9P2O5: 12K2O; 8–9 m formulation) applied as a top dress at 5.5, 11.0, 15.0, and 21.0 g/3.7-L container. The experiment was arranged as a CRD with 12 single-plant replicates of each fertility rate. Stock plant growth, cutting production, and subsequent rooting characteristics (percent rooting, root number, length) were evaluated for cuttings harvested at each of four harvests (30-day interval). Stock plant height increased as fertility rate increased for all harvests. After the first harvest, plant height did not differ among fertility rates above 5.5 g. Growth indices demonstrated that a 21.0-g application of fertilizer was necessary to increase stock plant size. The number of cuttings produced per stock plant increased linearly with increasing rate of fertility for all harvests. Cutting weight of individual cuttings increased linearly with an increase in fertilizer rate for harvests one and two, but cutting weight did not differ thereafter. The rooting response differed depending on the time of harvest. Percent rooting decreased with an increase in fertility rate for harvests two and three. Increased fertility rate did result in a decrease in root number for harvest one, but no further decrease was evident thereafter. Root length did not differ among harvest dates or fertility rates.