Prime Time for cool season grasses
We all love warm season grasses. In fact, Panicum, Miscanthus, and Hakonechloa are some of our personal favorites when it comes to ornamental grasses. But warm season grasses have their limitations in our climate since they require long days and warm temperatures to establish roots and grow, and they are some of the last perennials to break dormancy in the spring. On the other hand, cool season grasses will soon flourish as we head into the early spring months of April and May, and some evergreen varieties, like Festuca ‘Elijah Blue’, even put on growth beginning in late winter. While warm season grasses are not well- suited for fall planting, we can pot cool season grasses later in the season and still rely on them to root in before winter in preparation for spring sales.
One of our favorite cool season grasses is Sesleria autumnalis. Although this plant can be difficult to produce because of limited propagation windows, it’s a low- maintenance and adaptable grass once established in the landscape and it thrives in cool temperatures. We like to pot our Sesleria as early as possible in the season to allow it to establish roots before the heat and humidity of summer set in. Since it has no major pest or disease issues and is fairly drought tolerant, we couldn’t ask for a more trouble-free plant than Sesleria.
Calamagrostis ‘Karl Foerster’ is our most popular cool season grass, and also happens to be our top-selling plant overall year after year. Its popularity is probably due in part to its adaptability, low maintenance, and long-lasting blooms. ‘Karl Foerster’ can tolerate heavy clay, compacted soils, and urban environments, and is one of the first ornamental grasses to bloom, producing its characteristic wheat-colored seed heads in late spring to early summer. After it’s cut back in early spring, new growth begins to emerge quickly and this aggressive grower bulks up in no time. It is important to remember that ‘Karl Foerster’ is susceptible to rust, so siting it in a well-drained area will make it less prone to disease issues.
Festuca ‘Elijah Blue’ and Helictotrichon ‘Sapphire’ are two of the best drought-resistant cool season grasses that we grow. Each of these clump-forming blue grasses adds an interesting element of color and texture to the landscape, especially when they are used to highlight the blue flowers of companion plants or to complement the green foliage of other grasses. As with other cool season grasses, both Festuca and Helictotrichon thrive in cooler northern climates and do not perform well in extreme heat and humidity. These two cultivars are also especially sensitive to overwatering.
As spring approaches, we often receive early requests for warm season grasses at times when they are not naturally growing in the landscape. We have found that it works best for us and our nursery to work with nature and offer warm season grasses later in the season when they are actively growing in our climate. Cool season and warm season grasses complement each other so perfectly; while the Fescue and Sesleria are thriving in early spring, the Panicum and Miscanthus are still dormant. And just when the cool season grasses begin to slow down during the heat of summer, the warm season grasses are in their prime. By combining these two classes of grasses, we can take advantage of their differences to create low-maintenance, year-long interest in the landscape.
