Assessment of Fresh Miscanthus Straw as Growing Media Amendment in Nursery Production of Sedum spectabile ‘Stardust’ and Hydrangea arborescens ‘Annabelle’

The aim of this research was to assess the influence of fresh miscanthus straw shreds as a component of growing media in nursery production of perennial Sedum spectabile ‘Stardust’ and woody shrub Hydrangea arborescens ‘Annabelle’. A total of five substrate mixes composed of peatmoss and miscanthus straw were used: 100%P, 70%P:30%M, 50%P:50%M, 70%P:30%M, 100%M. Each substrate was subjected to three fertilizer treatments: Basacote, Basacote + YaraMila, and YaraMila. The growth response of both tested species was very similar. In general, plants performed best in 100%P, and the quality decreased with increasing miscanthus straw amendment; however, differences in height and dry weight at the level of ~9% suggest that Sedum plants obtained market value with up to 50% miscanthus amendment and Hydrangea plants with up to 30% miscanthus mixed in media. The most favorable effect on the tested parameters was a combination of Basacote + YaraMila, which delivered more soluble salts, and in higher rates than Basacote and YaraMila used separately. Decrease in EC and nutrients in the substrate with increase in miscanthus straw amendment suggest that uniform irrigation among all the treatments contributed to nutrients leaching from miscanthus media due to its lower water holding capacity.