Top 5 Cold Hardy Annuals You Can Start TODAY!

January is the time of year when gardeners are dreaming up their garden for the year and go on a seed shopping frenzy! Before you buy, I wanted to share some of my tried and true cold hardy flowers that have become favorites over the years. Bonus? They make wonderful cut flowers!

Feverfew (Magic Lime and Virgo), Sweet William (Jolt Pink Magic), Scabiosa (Fata Morgana), Orlaya and Snapdragon (Costa Silver)

First thing's first. Know your growing zone!

Here in Knoxville, TN I garden in USDA Hardiness Zone 7a (find your gardening zone here). Knowing your hardiness zone tells you when your first and last average frosts are which in turn help determine:

• when to start seeds

• what plants constitute as an annual or a perennial

What is an annual vs a perennial?

Simply put, a perennial plant will come back year after year while an annual plant must be replanted each year (annually). Cold hardy annuals are a special kind of annual that thrive in cold weather conditions. They can survive freezing temperatures, are typically the first blooms in mid spring and will often reseed themselves for the following spring.

How do I know what is cold hardy annual?

The back of your seed packets will offer guidelines as to when to start seeds and what type of plant they are. They will usually note if they're a "tender perennial" (meaning they may come back each year depending on your growing zone or may need to be replaced after a couple seasons), perennial or an annual. Most hardy annual seed packets may say "cold hardy up to Zone 7" or "frost hardy" or "sow as soon as the ground is workable".

My top 5 favorite cold hardy annuals to grow

1. Scabiosa (pincushion flower)

   
   

Scabiosa is one of my new favorite flowers to grow. It can overwinter well and becomes a pollinator's paradise in early summer. You can grow these in successions and are considered cut and come again flowers. (Note: some scabiosa are sold as perennials at the hardware store. These plants will come back year after year and make a wonderful addition to your landscape-- and are short! If you're growing these for cut flowers and want long, straight stems, you'll want to start these from seed.) They come in mostly berry tones (pinks and reds) with occasional purples and a creamy yellow (fata morgana). The seeds are plentiful and very easy to collect. For the longest vase life, harvest these when the outer petals start to open but the central petals are still closed and look like little balls. Scabiosa will continue to open in the vase!

2. Feverfew (Matricaria)

   
   

Y'all. I LIVE for the fragrance of feverfew. If allowed to self-sow, they will continue to come back year after year. Or you can start seeds every fall/winter. They overwinter well without protection and come in a variety of flavors. My favorites are the Magic Single (photo on the right) and Magic Lime Green (photo on the left). Virgo (center photo) was a new-to-me variety that grew impressive, straight 4' stems! All of the blooms congregate to the top of the stem while the other Magic varieties are more spread for a broader coverage look. If you're after that cottage garden look for your landscape or bouquets, you want to grow feverfew. They will produce a wonderfully strong, straight stem their first flush and produce shorter but still full blooms in subsequent flushes. Feverfew can also be dried out and saved for year round enjoyment. Harvest when 3/4-fully open for full enjoyment.

3. Sweet William (Dianthus)

   
   

This was a new-to-me flower last year and I am HOOKED! In the carnation family, their vase life is impressive, just as the classic carnation I grew up enjoying each Valentine's Day. These flowers are interesting little green spikey balls before they bloom and then open to the most delicate little ball of flowers. They come in a variety of pinks and reds--some mixed, some uniform in color. If allowed to go to seed, they will easily self-sow and you'll have more plants in their place the following spring. I've found they offer one great, usable stem for bouquets and if cut to the ground, they will send up smaller, narrower stems throughout the growing season. Harvest when the majority of the flowers are open and they will give you a 10-14 day, vibrant vase life.

4. Snapdragons

I love snapdragons. They offer such a unique visual to any bouquet and pollinators love them. There are so many varieties and colors it can be hard to choose which ones to grow. Snapdragons are categorized into 4 different growing groups based on their light needs and heat tolerance (you can find more information here). I swear by Potomac snapdragon and the Opus III Early Bronze varieties. They seem to be the most heat tolerant with our early summers, overwinter well with protection and can be grown in many successions through the entire growing season fall to summer. When overwintered, they are the flowers I expect to have over Mother's Day and fill the lull between spring blooms and the beginning of summer annuals. They grow one very strong and sturdy stem and if cut above a set of leaf nodes, they will usually grow two narrower, smaller stems from that node. Depending on what your growing goals are, you may choose to plant multiple successions to guarantee that one usable stem or just enjoy having these spikey blooms waving in the breeze and seeing little bumblebee bums hanging out of the blooms. Harvest when the bottom 1/3-1/2 of the buds are opened for the longest vase life.

**Note: If you want to have STRAIGHT stems, you MUST support these plants! They will grow any which-way and you will end up with very wonky stems otherwise. I like to use some sort of grid netting (Horotnova is a love-hate relationship among flower farmers) placed ~6" above my snapdragons (sometimes a second layer 6" above that one) to allow the stems to grow up through the squares to provide support for the tall stems.

5. Rudbeckia

Rudbeckia - Black Eyed Susan. A classic summer flower. Did you know they come in many different mixes? The classic bright yellow petals and Sahara and Caramel mixes have become a fast favorite among growers. Some come as more of a bush variety with multiple flowers branching from one stem and some (as pictured above) are multiple single stems coming from the same plant. They overwinter with no protection and can also be started in the spring for multiple successions throughout the growing season. Harvest by cutting down the ground once the flowers are completely opened.

Bonus: Orlaya

This is such a beautiful addition to the landscape or your arrangements. Orlaya is very hardy and self-sows like bananas. Grow one plant, let it self-sow and you'll have 50 the next spring. They are a little fussy when it comes harvesting and it takes a few times to get the timing right, but once you figure it out, they make a very whimsical element to your arrangements. I've learned to harvest when the outer ring of flowers are open and the most central ones are almost completely opened to give the longest vase life.

Overwintering Hardy Annuals

I know I've been talking a lot about overwintering these hardy annuals. What does that mean? Overwintering is simply planting these seedlings in the fall (about 6 weeks before your first frost), allowing them to grow until winter and they will pause their growth during the coldest part of the winter. Some plants prefer protection from the elements like a frost cloth or a plastic row cover, and others do well with no protection. Once early spring arrives and the temperatures start to warm up, these flowers continue their growth and are some of the first to bloom in spring with your tulips, ranunculus, daffodils and anemones (or shortly after).

When to start seeds

In Knoxville, I will start these seeds in July, plant them out in September and let them do their thing until spring. Giving them about 6 weeks before your first frost allows their root system time to develop and mature before frost arrives. This gives the plant a better chance of survival over the winter. I also plant these hardy annuals in successions. Successions give you continuous blooms instead of one harvest from one planting. For example, with snapdragons, I will plant some in the fall in September and then start another succession in December-January and plant them out in March. Then I'll start another succession in mid February and plant out in April. Then I may start another succession in June for a fall harvest in September before starting my overwintering succession. Depending on space, I may only start seeds for my fall planted snapdragons, two more successions and call it good for the growing season. Then replace the snapdragons with a fast growing, heat lover like zinnias, celosia or sunflowers.

The point is, it's not too late to start these seeds and get them in the ground in March for some early spring blooms I know you'll fall in love with.

What are you looking forward to growing this season? What does your garden plan include for 2025? What questions do you have? Stay tuned for an article on summer lovin' annuals you'll want to add to your grow list this season.