A Grower's Guide to Snapdragon Group Numbers and Season Planning

It’s no surprise I’m often asked why we offer such a wide variety of snapdragons! These stunning, whimsical flowers have a lot more going on than meets the eye, and when you dig a little deeper, it all comes down to understanding their “group” classification.

Snapdragon varieties are divided into Groups 1 through 4, and knowing these groups can be a game-changer if you’re a gardener or grower looking to get the most out of your blooms. Each group is assigned based on how these flowers respond to light, day length, and temperature—essential elements that directly impact when and where they thrive.

Let’s start with Group 1, the “cool season” snapdragons. These are perfect for short days, low light, and cool temperatures. Think fall and winter greenhouse settings, or early spring if you’re in a mild climate. Their natural resilience in lower temperatures lets them bloom beautifully when other flowers might not stand a chance. This makes Group I varieties a favorite for extending the season when most flowers are out of production.

Group 2 varieties take things up a notch with a bit more flexibility, handling moderate heat and light. They’re perfect for bridging cool and warm seasons, allowing growers to extend blooming into late spring and early summer. If you’re working with spring field plantings, Group 2 snapdragons can help you hit your stride right as the temperatures start warming up.

Now, Group 3 snapdragons are what I like to call the “sweet spot”. These varieties are moderate-to-warm season champs, thriving under medium-to-long days and higher light levels. Whether you’re dealing with a mild spring or an unpredictable summer, Group 3 offers incredible versatility and consistency. These varieties can seamlessly fill in gaps in your growing calendar, ensuring you always have vibrant, sturdy stems and high-quality blooms ready for market or home decor.

Finally, Groups 3-4 and 4 are your classic warm-season choices, needing long days, high light, and warm temperatures. Their slower growth and delayed blooming make them ideal for summer production, allowing them to develop those tall, strong stems and full, showy blooms. However, remember that even these heat-tolerant varieties can have their limits—too much heat over a prolonged period can stress any snapdragon.

The beauty of understanding these group classifications is in planning a continuous cycle of blooms. By strategically planting a mix of Group 1, 2, 3 & 4 varieties, you can enjoy (and sell!) a consistent flow of snapdragons nearly all year long. This approach isn’t just practical; it also helps with resource efficiency. Selecting varieties suited to your current conditions can reduce the need for artificial lighting and heating, saving on costs and reducing your environmental impact.

For those of you selling cut flowers, mastering these group numbers is essential. Knowing which varieties will produce long stems and lush blooms under specific conditions allows you to meet market demands with top-quality flowers, keeping your customers delighted year-round.

And here’s a fun fact: snapdragons aren’t the only ones with group numbers—Lisianthus uses a similar system to guide their growing conditions too!

So there it is! By understanding snapdragon group numbers, you’re not only growing flowers but also crafting a reliable, blooming schedule that’ll keep your garden and customers happy through the seasons. Embrace the power of this system, and you’ll be unlocking your garden’s potential in ways you may never have expected.