Start Planting Cool Season, Hardy Annuals for Spring Flowers

snapdragons in the spring

Now is the time to start thinking of planting cool season hardy annuals. This is a group of annuals (grow and die in one season) that can survive the winter and thrive in cool spring weather. In the Washington DC metro area, they are planted in the fall and bloom in the spring. They spend the winter getting established so when spring arrives, they are ready to bolt out the door waving their pretty flowers before the warm season summer annuals appear.

Examples of cool season annuals are snapdragons (Antirrhinum majus), calendula (Calendula officinalis), bells of Ireland (Moluccella laevis), delphinium (Delphinium), lisianthus (Eustoma), love in a mist (Nigella), sweet peas (Lathyrus odoratus), sweet William (Dianthus barbatus), and bachelor buttons (Centaurea cyanus). Many of these make great cut flowers.

I credit everything I have learned about cool season hardy annuals to Lisa Mason Ziegler and her book, Cool Flowers: How to Grow and Enjoy Long-Blooming Hardy Annual Flowers Using Cool Weather Techniques.  Lisa manages a commercial cut flower business in Newport News, which is in Zone 7, similar to my Northern Virginia garden. In addition to growing and selling cut flowers, she writes books, gives lectures, provides free videos as well as Facebook Live presentations, and manages a website called The Gardener’s Workshop.

Several years ago I was inspired by her book to plant calendula and snapdragons in the fall. I was starting them in the beginning of the growing season and was not having great success. The weather became too hot before the snapdragons could bloom and the calendula foliage was covered in powdery mildew because of the summer’s heat and humidity. When I tried her method of starting them in the fall, they both bloomed early enough the following spring that I was able to enjoy the calendula flowers before powdery mildew set in and cut many snapdragons for indoor arrangements.

calendula flowers in the spring

This year, I plan to grow sweet peas, which I have not been able to master in the spring. Our springs are just too short to have a long blooming period. I bought a package of Botanical Interests ‘Old Spice Blend’, a fragrant, heirloom blend of various flower colors. Interestingly, sweet peas are deer resistant and attract pollinators but I am going to grow them for indoor flower arrangements so I can enjoy their beautiful, fragrant flowers in the office.

Although Lisa provides specific information for 30 flowers in her book, in general, we should start 6 to 8 weeks before the average first frost. In Northern Virginia, 8 weeks is August 31 and 6 weeks is September 15. She recommends to err on starting later rather than earlier. Some seeds can be sowed directly in the garden while others work well as transplants. Sweet peas can be done either way so I am going to do both as an experiment to see which works better in my garden. I will start half of the seeds indoors under lights and half outdoors, directly in the garden. In order to have transplants large enough to move into the ground around September 15, I would have to start sowing seeds around September 1. Then I can sow the remaining seeds around September 15. September is still a very hot month so I will have to remember to water often. If this works, next year I will post a photo of the sweet peas.

If hardy annuals are something you would like to try, you can catch up by visiting Lisa’s website, listening to her videos, and reading her book. Although she sells seeds and gardening products, you can also purchase seed packets at your local independent garden center. Good luck!