I stumbled into learning about cool-season hardy annual flowers a couple of decades ago. My interest had been sparked by flower farming and I wanted to jump in with both feet, but we were heading into winter, what now?
While I knew practically nothing about farming at this point, I did know this: I didn’t have funding to start purchasing quantities of bulbs and perennials, the classic fall plantings. Then I read about a group of flowers that could be started from seed and preferred cold weather. I learned these cool-season hardy annuals didn’t just survive cold weather, but in fact, it is their secret sauce!
There are so many misconceptions about cool-season hardy annuals and much of it is rooted in the word “annual”. The most well-known and popular annuals are warm-season tender annuals like tomatoes, basil, zinnias, and others. Folks instantly think of this group and their needs when they hear that word “annual”.
But, oh boy, have we been missing out on some of the best flowers to grow! There is a whole pack of cool-season hardy annuals to include in the cash crop lineup: bells of Ireland, snapdragons, sweet William, poppies, sweet peas, and others. Some of the most beloved spring flowers and those in high demand in the commercial floral trade.
These cool-season annuals follow the same life cycle as warm-season annuals but have a very different planting timeline and few of us get it right. The secret ingredient that determines success and longevity of harvest is when they are planted.
Optimal Planting Times
6-8 weeks before the first fall frost for those hardy annuals
that are winter hardy in your growing zone. There are several for even the coldest zones.
Very Early Spring Planting:
6-8 weeks before the last spring frost for those hardy annuals not winter hardy in your growing zone. Plus a repeat planting of some of the fall plantings to extend the bloom season.
Tips for success:
- Fall planting should be done in a timely manner for the best success. Transplants need time to become established and direct sown seeds need time to germinate into a small plant before below freezing weather sets in.
- Early spring planting beds must be prepared in fall and held over until early spring. Soil is typically frozen, wet, and or covered in snow that prevents preparing beds at the proper planting time.
- All hardy annuals appreciate excellent drainage as moisture lingers in cold soil.
- The wind protection of lightweight row covered low tunnels gives significant benefits beyond temperature control.
- Whenever a plant is winter hardy in your growing zone, it is beneficial to fall plant it. These well-established plants bloom earlier, have better disease and pest resistance, produce more abundance and stem length, and produce quality longer into the heat and humidity of summer.
This group of hardy annual flowers has become known as Cool Flowers in the flower farming industry. They are named for my book Cool Flowers on this subject that has rekindled the practice of cool-season hardy annuals playing a major role in fields and gardens worldwide.
Do a little digging and you’ll find that this practice of planting cool-season hardy annuals on the brink of cold weather beginning or ending was practiced in days gone by our grandparents and beyond. I contend that as folks became disconnected from gardening and home seed starting in the past decades, this group of plants and their awkward planting times plants fell to the wayside.
Once I learned the needs of these cool-season hardy annuals and found their best planting times for my farm, they have become the most carefree crops I grow. The bonus, they typically produce in spring which is the highest demand season of all.
It is so special to me that cool-season hardy annuals are affectionately known as Cool Flowers…
Lisa Mason Ziegler is a cut-flower farmer, author and nationally recognized speaker on organic cut-flower farming.