While clearing leaves from perennial beds and cutting spent stalks of perennials, my mind was busy plotting to make this season’s container display exceptional.
Every year I settle (loosely) on a color scheme and begin acquiring annuals from mid-April through mid-May, purchasing healthy plants and carefully tending them as they transition from the greenhouse to the outside world. This process of "hardening off" involves keeping the starts watered and in a partly sunny area allowing the plants to adapt to the fluctuations in day and night-time temperatures outside of the safety of the greenhouse. Most importantly, monitor the low temperature predictions and be ready to pull the annuals inside if temperatures dip below 40 degrees.
The bulk of my container choices are stalwart species that have performed consistently well in my garden for years, however, I'm always on the lookout for exciting new cultivars introduced by plant breeders. Be open to new introductions, do a bit of research and incorporate one or two into your plan. Sometimes the new addition inspires a completely fresh combination of plants. That serendipitous moment is one of the best parts of container gardening- it's never static and the creative process adds to the fun. It is wise to hold off on purchasing a few plants until later in May, when minimum night-time temperatures no longer dip below 60 degrees. Late May and early June are prime time to find exciting tropical plants and interesting heat loving vegetables which would languish in the cooler days of early May.
The urge to get planting before our average last frost date- May 26 in the Pittsburgh area, can be satisfied by flowers that relish cooler temperatures including: pansies and violas, snapdragon, African daisy (Osteospermum), Nemesia, and forced bulbs. This year I've decided to fill the entire cache of containers dotting my landscape with good quality soilless mix and am direct sowing the seeds of cool season vegetables in advance of the warmer temperatures that are a good two months away. You can also purchase seedlings of cool season vegetables from garden centers, especially plants that take months rather than weeks from seed to harvest, such as broccoli or cabbage.
The energy I have heading into gardening's "prime time" will allow me to get a head start on the laborious process of filling the pots with fresh soil, while the temporary inhabitants of each pot will provide fresh produce for my kitchen.
Of course, you can plant cool season vegetables in the vegetable garden, or even in the mixed border, but my strategy is to get the containers out and filled, making them do double duty with a fresh spring look followed by a summer show.
Once we head into consistently hot weather these many of these cool season veggies bolt i.e. produce flowers and seed and their leaves become tough and bitter. The timing is perfect to enjoy cool season annuals at their peak, then follow them up with tomatoes or geraniums, examples of plants that relish heat and humidity.
For optimal performance of cool season vegetables provide at least six hours of sun. Some ideas to inspire include:
- Choose a mesclun mix with a range of colors from pale green to burgundy, add pansies with the same bronze and golden shades, top off with bright yellow daffodils.
- Plant some pepper-y flavored dark green arugula alongside the frilly leaves of parsley. Add colorful bulbs- tulips, daffodils and grape hyacinths to name a few, for a bit of flower power.
- Anchor a container with the dramatically colored stems of Swiss chard. Choose flowering or foliage plants to pick up the stem color of the chard- including bright yellow calendula or dwarf snapdragons.
- Plant beets, radish or carrots along the edges of a container, allowing them to stay in place for a bit longer to harvest. In late May center a tropical plant in the container, such as hibiscus, or an heirloom tomato. Harvest the root vegetables and be sure to utilize their flavorful greens. Plug in some nasturtium seeds or add some other "spiller" annuals to trail down the sides of the container once the vegetables are mature.