Think Spring...Container Style! - May 12, 2014
By: Lindsay Hendricks, Horticulturist at Green Bay Botanical Garden
“If we had no winter, the spring would not be so pleasant…”—Anne Bradstreet
What better way to welcome spring than with a pretty spring container? To get started all you will need is a container, soilless media, and some cool-season plants.
First, choose a container that has drainage holes and can accommodate the mature size of the plants. And why not spice things up a bit and choose bright, glazed pottery or an old leaky watering can over traditional terra cotta? Second, choose a high-quality soilless media (not potting soil) that contains a mix of peat moss, perlite, and other nutrients essential to plant growth. Here at the Garden we use Fafard 3B—it may cost a little more but when it comes to soilless media, you get what you pay for. And because it is too heavy to support container plant growth, never use topsoil or garden soil in any container. At the Garden, we also add slow-release fertilizer—Osmocote—to our soilless media to help feed our plants every time we water. Add 1 pound of Osmocote for every 2.8 cubic feet of soilless media used. To avoid areas of highly concentrated fertilizer, make sure to mix the media and fertilizer thoroughly before adding it to a container.
Now you need to select your plants. But what is a cool-season plant, you ask? Have you heard the phrase “some like it hot, some like it cold”? Well some plants like to grow in warm weather while others prefer to grow in cool weather. For example, zinnias, geraniums, and begonias like warm temperatures and will not thrive in cool spring conditions. However, annuals such as pansies, trailing pansies, snapdragons, alyssum, nemesia, and osteospermums thrive in cooler temperatures and can even tolerate a light frost. Want to add interesting foliage and some pizazz to your salads? Add cool season edibles such as lettuce, Swiss chard, beets, and kale to your spring container. If you plan ahead you can also use bulbs such as tulips, daffodils, or hyacinths in your spring containers, but they must be planted the prior fall. However, if you are short on time head to your local garden center and purchase pre-chilled bulbs. Just make sure to acclimate them to the outdoors before planting. Finally, no matter which plants you choose, make sure they share similar requirements for light and soil moisture if they are to be in the same container. Like I always say “Don’t plant a cactus with a hosta!”
Now onto the fun part, designing your container. To start you can follow the ‘Thriller, Filler, Spiller’ rule. A thriller is a plant that grabs your attention with tall, upright form or bold foliage, such as Swiss chard or Redbor kale. A filler is a plant that fills the majority of the space in your container such as pansies, snapdragons, lettuce, or osteospermums. Finally, a spiller is a plant that cascades down the sides of the container, such as alyssum or a trailing pansy. To take your container to new heights (literally) try adding branches of curly willow, pussy willow, or forsythia. Feel free to ignore this rule though, and design a container that looks pleasing to you…that is the beauty and fun of container gardening!
After creating your masterpiece, you will want to follow a few simple steps to keep your container blooming as long as possible. First, check for water daily especially on those warm, sunny days. Simply stick your finger into the soil up to the second knuckle: If the soil feels dry, add water. If the soil feels wet, don’t water. And since annuals are heavy feeders, you will need to fertilize weekly with a water soluble fertilizer such as Miracle Grow. You can also add a slow release fertilizer, such as Osmocote, to your soilless media at planting time. Keep up on deadheading (removing spent flowers) to encourage repeat blooming.
When your lettuce starts bolting, you will know it’s time to transition your container to warm-season plants…the ones that like it hot! There are two ways to go about the transition. The easiest way is to toss all your spring bloomers in the compost and start over from scratch. The second option—for everyone out there (like me) that just can’t bear the thought of throwing a living plant in the compost pile—is to simply pull out your tired looking plants and replace them with warm-season plants. Typically I will remove my pansies and snapdragons (sometimes the whole root mass) from containers and transplant into flowerless-gaps in the garden. Then I fill the gaps in the containers with warm-season plants such as zinnias, petunias, angelonia, or geraniums. At this time I also harvest and edibles and enjoy them in my salads. If there were any bulbs in your container, once the blooms and foliage have faded, gently lift them from your container and plant them in the ground for a beautiful display the following spring.
So gather up your favorite containers, soilless media, and spring flowering plants and get ready to have some fun! Follow the thriller, filler, spiller rule or come up with your own. Remember to check for water daily, fertilize weekly, and deadhead regularly. Once summer rolls around you can completely redo your containers or transition them into summer blooming beauties. Be creative, and most of all have fun. Now, who’s excited for spring!?