Effects of Irrigation Frequency and A Water-Absorbing Polymer Amendment on Ligustrum Growth and Moisture Retention by a Container Medium

Amending a 2 pine bark: 1 Canadian peat: 1 sand (by vol) container medium with 0, 1.2, 2.4, 3.6 or 6 kg/m3 (0, 2, 4, 6 and 10 lbs/yd3) of a water-absorbing polymer, Moisturite3, did not influence the volume of water held at tensions less than 100 cm (39 in). Greenhouse-grown Ligustrum japonicum wilted when irrigated (920 ml/application; 31 oz) every 12 days; however, more frequent irrigation treatments (every 6 and 3 days) reduced shoot and root dry weights. Dry weights were not affected by polymer amendment rates nor were container medium temperatures different 1, 2 or 3 days after irrigation.