For my window boxes I usually choose primroses in the spring and petunias in the summer and early autumn. This year I wanted to save money by not having to replant mid-season, so I decided to try Swiss Giant Pansies. What a great choice! The resulting plants are doing wonderfully and since I didn’t use the whole seed pack, my lovely window boxes cost me just pennies!
Plants in window boxes need to be able to endure three primary challenges, which I am sure are shared by many other window box gardeners:
Eaves block the summertime sun.
Being up under the protection of the eaves on the south facing side of the house, my window boxes get the most direct light during early-mid spring and mid-late autumn. They get the least direct light during the summer when the sun rises above the eaves for most of the day. This can make sun-loving plants like marigolds or petunias grow gangly or make them reluctant to bloom. Pansies, I thought, might prefer not being bombarded with high summer afternoon sun.
Small shoes for plant feet.
Window boxes have limited root space, since they are just relatively small pots. Some plants like to spread their roots while others are quite happy in a cramped space. Besides succulents (like Hen and Chicks) pansies have always been the happiest outdoor potted plants that I’ve had. In fact, I have a pot of pansies that has reseeded itself for the past 3 summers in a row! Pansies don’t mind the limited space… in fact, they seem to thrive. Just one more reason to try pansies in window boxes.
Window Boxes are typically up next to the house where the solar heat can collect and make temperatures toasty. Yet on a spring night the temperature can still drop below freezing. Plants in window boxes need to be hardy and willing to endure extreme variations in temperature, especially if they’re going to last all season. Pansies are perfect! While they prefer cool sunny spring days, they’re also very happy to endure heat (if they’re not in direct sun).
I decided that pansies were indeed worth a try, so in mid spring I bought some Swiss Giant Pansy seeds and planted them in starter trays in the greenhouse. I thought perhaps late-April was too late, but I was wrong. I had pansy sprouts within two weeks and by June I had nice young plants ready for my window boxes. By July the waves of blossoms began and even now in mid-August they’re still going! In fact, it seems I need to prune them some. 🙂
Note: Deadhead your pansies to promote new blossoms. You can even carefully prune off parts of the plant that get to leggy to encourage the plant to grow more compact.