Article and photos by Michael Strengari
Designing containers is a gratifying activity and can immediately transform an outdoor space, no matter the size. After joining the talented team at Mt. Cuba Center in Hockessin, Delaware, I was tasked with creating container displays, with the caveat of using all native plants from the eastern temperate forest region (with some wiggle room). I was ready for a new challenge! Over the past few seasons, I relied on my previous container design experience to create appealing displays that enhance the garden spaces and to share with guests the beauty of our local flora.
By now most gardeners are aware of the ecological benefits of using native plants in gardens. Why not use them in containers? Container gardening with native plants allows individuals with limited space to support biodiversity while beautifying their outdoor area, even if all they have is a front stoop in the city. If you do have a large garden with plenty of in-ground space, using native plants in containers is a great way to highlight your favorite plants and grow those that you may not have the proper soil conditions to grow in the ground. Container gardening offers the ability to create the conditions to suit very specific plant needs. For example, I love bog plants, but the wooded hill I live on is certainly not boggy. Growing bog plants in containers allows me to enjoy these wonderful species, even on my patio.
While many of the basics of container gardening with native plants is just like using other ornamental plants, it does present some unique challenges. One difficulty of container gardening with native plants is that many that are available are perennial, and some of those grow slowly. Many do not grow to become a worthy specimen plant in just one season. That is where some basic plant knowledge comes in handy. I never buy a gallon-size bluestar (Amsonia hubrichtii), false indigo (Baptisia), or even a culver’s root (Veronicastrum virginicum) and expect them to become a robust showstopper in just one season. Instead, I shop for plants that will fill out much faster, like beebalm (Monarda), tickseed (Coreopsis), or Hibiscus. Another challenge is the ephemeral nature of the bloom time with perennial plants. To address that challenge, I look for plants that have a longer bloom time, an interesting seed structure, pleasing foliage, or a combination of all three. When there is a plant I want to display regardless of having those characteristics, I just plan on switching out the single plant or whole container to give the opportunity to display something else that looks great.
Pitcher plants for all-season interest
We display pitcher plants (Sarracenia) in containers annually. They are surprisingly easy to grow, offer a full growing season of interest and beauty, and allow for educational engagement. Sarracenia are aesthetic oddities. In spring their flower buds are hanging orbs that open to shower head-shaped structures. Flowering is followed by a flush of foliar growth in a multitude of colors with gorgeous venation patterns. Sharing their unique adaptations always fascinates guests. Creating a stunning container display with pitcher plants is a breeze.
- Use a sturdy container and cover the hole so that it will drain slowly.
- Mix an equal amount of peat moss and sand for the potting media.
- Don’t fertilize or add compost.
- Don’t worry about maintenance, which is minimal. Simply cut back pitchers as they turn brown.
- Overwinter containers in a cool space where they will not freeze (a garage or basement works great).
- Divide and re-pot pitcher plants once every two years.
Containers with a purpose
We plant containers for many reasons. I like to use containers that support garden spaces to help set the mood, define a space, add seasonal excitement, or frame a view.
Pink muhly grass (Muhlenbergia capillaris) and willow-leaf sunflower (Helianthus salicifolius ‘Autumn Gold’ ) in foreground
This set of matching containers flanks the intersection in front of the Main Terrace. Not only are they beautiful on their own, but they are placed in that location to remind guests to pause and hopefully admire the view over the hills of the Delaware piedmont. Sunflowers line the steps up to the terrace, drawing the guest to another space.
Sometimes simple is more pleasing to the eye than a busy container. I am beginning to use mixed containers more sparingly in favor of containers highlighting a single native plant. I find it is easy to set the mood of an area using different types of plants. Plants with many brightly colored flowers show excitement, while plants with lush green foliage evoke a sense of calm and relaxation.
This pair of containers in the shade of the Main Terrace highlights two of our native woodland plants. Just like a woodland, they should conjure up a peaceful feeling. These containers invoke the same philosophy while bringing a little bit more color to the space. Cover the soil with some native moss. It adds a little charm, and no one wants to look at potting mix. Please source your moss from a grower rather than wild collecting it.
Left container featuring ostrich fern (Matteuccia struthiopteris) with pincushion moss (Leucobryum glaucum). Right container filled with wild ginger (Asarum canadense).
Woody plants not only anchor a container grouping but can also be used as a focal point. This stunning young magnolia is drawing guests in with its massive flower. When not in the flower the large tropical leaves continue to create a lush green in this relaxing space.
Container groupings are an easy way to make an impactful seasonal display. Some plants can be displayed throughout the whole season while other containers can be swapped in and out to create seasonal magic. In mixed containers, if one plant is losing its aesthetic appeal, it can be swapped out quickly with another. Combining multiple textures, plant forms, and types can display a diverse array of the plants we promote.
Container fertility
When planting containers, I prefer to use a potting mix without any added fertilizer. Most of our native plants’ nutrient requirements are much less than exotics. Instead, I opt to add a bit of compost to the mix, though usually no more than one fourth of the potting mix is added compost. I fertilize biweekly with a balanced organic liquid fertilizer after watering. This approach allows me to use a sustainable product and have full control of the amount of nutrients available to the plants.
Michael Strengari is a Senior Horticulturist at Mt. Cuba Center, where he works in the Formal Garden. During his career in horticulture, he has gardened private estates, public institutions, and his home. He is a graduate of the Longwood Gardens Professional Gardener Program. Throughout his career he has shared his enthusiasm for gardening and knowledge as an instructor, speaker, and mentor to students and colleagues. With an eye for design and a passion for native plants, he hopes to continue to inspire the public by creating and maintaining beautiful garden spaces. While he is proud of the many gardens and displays he has created, he is most rewarded by the connections that these projects make with the public. When he is not in the garden, you can find him exploring nature with his dog, reading a thriller, or relaxing on the beach with his partner.