Each summer the front entrance to the Gardens is filled with containers of all sizes featuring annual plants bursting with color. This summer is no exception; although this year these containers feature “More than Meets the Iowa”. With the 2013 theme being all about Iowa, horticulture staff have used Iowa’s prairie landscape as inspiration for the front entrance. Rather than the traditional petunia, sun-loving coleus and verbena the containers are planted with prairie plants. While it may seem odd to use perennials in annual summer containers, there is really no rule book that says you can’t try it. This summer the containers are overflowing with prairie grasses like tufted hair grass (Deschampsia cespitosa), prairie dropseed (sporobolus heterolepis), and various cultivars of switchgrass (Panicum). Flowering plants include interesting and new cultivars of prairie favorites like coneflower (Echinacea purpurea ‘Pow Wow Wild Berry’), anise hyssop (Agastache foeniculum), and spiderwort (Tradescantia ‘Sweet Kate’) as well as plants almost exclusively associated with prairies such as yellow coneflower (Ratibida pinnata) and scaley blazing star (Liatris squarrosa).
When selecting perennials to use in container gardens bloom time and interest are important considerations. Many perennials have a limited season of bloom, making them difficult to use in a container where color and bloom is wanted all season. Select perennials for this type of use that have interesting foliage, such as many of the prairie grasses used in the containers at the front entrance of Reiman Gardens or plants like hosta (Hosta) or coral bells (Heuchera). Other perennials can be encourage to rebloom throughout the season with deadheading, such as bee balm (Monarda), Shasta daisy, (Leucanthemum), and Culver’s root (Veronicastrum). Still others like many of the new varieties of black-eyed Susan (Rudbeckia) and coneflower (Echinacea) do a good job of reblooming all season on their own.
When using perennials in annual containers they don’t have to be tossed at the end of the season. Any cold hardy perennial should be pulled from the container in the fall and planted in its new permanent home before the ground freezes. Overwintering can be done in the container, but only if that container is heeled into the ground to protect the roots which tend to be less cold hardy than the crown. Be sure to water fall planted perennials well throughout the season and most benefit from an extra layer of mulch to get them through the first winter.
Stop out to the Gardens and see all the containers newly planted with colorful perennials and annuals and keep an eye on them all summer. They only get better with time!
Prepared by Aaron Steil, Manager of Public Programs