I am NOT an expert on this topic. I just want to share a little secret with you that the big box stores selling delphiniums in July have lied to you about. There are major differences between annual flowers. Not every annual flower seed likes the warmth of summer as many are led to believe. Here’s the big thing: not every seed or plant being sold during a particular time of the year is actually meant for that time of year! Read that again. Yes, I mean that. You would think that a retailer selling a product would sell that product during the time that it should be planted but that’s just plain NOT true.

I’m sorry to be the bearer of bad news but now you know!

There are two groups (generally; we’re not going to touch on biennials right now). There are cool season annuals and there are warm season annuals. Cool flowers are just another name for cool season annuals. As a general rule, these are your spring blooming flowers and they either don’t like growing in the warmth or they need to be started in cool weather in order to thrive.

All of those garden favorites from your grandmother’s garden: snapdragons, poppies, larkspur, Canterbury bells, delphinium, sweet peas…these are all cool flowers and they will likely fail you every single time if you start them in the heat of summer.

Most people can understand this concept if you relate cool flowers to spring bulbs like tulips or daffodils: those bulbs must be planted in the fall in order to flower in the spring. The reasoning for this is temperature. The bulbs MUST have a minimum period of cold temperatures in order to flower. This is why you don’t see tulips in the deep south. If you do, they’ve 100% been pre-chilled artificially (in a special cooler) for that period of time and then planted ready to bloom.

Cool season annuals are a bit similar, though each has different needs. I don’t want to get too far into the weeds here but even within cool flowers there are differences in starting needs. Some need a freezing period, some need a cool period, some actually do OK with a warm start but then need cool temperatures to grow on, and some need a little of each. BLAH! It’s complicated. I totally agree. That’s why I started this post with the disclaimer that I’m not an expert. I’m absolutely still figuring it out myself. I’ve improved a lot in the past 5 years. Especially with my germination success. I still sometimes struggle with those varieties that are not winter hardy but still require a longer cool period. The timing is the trickiest part.

What this all means is that there are many plants (flowers and veggies too) that can actually (and SHOULD actually) be started WAY before you ever thought. Like a month + before spring actually starts. Some even earlier and some started in the fall just like the bulbs I talked about.

Let’s take a favorite of mine as an example: snapdragons. I will touch back on how my overwintered trial did this season. Right now, if I’m being honest, they look like total and utter poo. I think I let them get a little too big and didn’t pinch them hard enough before being smashed by several snowfalls (snow is great for cold hardy flowers otherwise). I have started several hundred (thousands?) more to be planted this spring just in case. I can’t go through another snap-less season!

So snapdragons are a very hardy cool flower. In our central PA zone 6a (leaning 5b), they do very well IF planted at the right time. Finding that right time is the tricky part. Snapdragons need about 16 to 17 weeks to grow to full blooming maturity. That’s quite a long time in plant world. This adds another layer of trickery to snaps. Our local last frost date is about the first week of May. Snaps are hardy and can take freezing temps if hardened off well. Starting at the end of March to the beginning of May is when I would be planting out snap seedlings if I were a local home gardener. But to do that, you need to have baby snaps to plant. That means having planned to start them many weeks back, about 10 to be specific. That means starting seeds inside at the end of January/early February to have seedlings big enough to tolerate those early spring conditions.

So now that I’ve confused you even more…let me break it down a little better. Think about what cool flowers you love and would like to grow next season. Buy them this summer or fall so you have your seeds ready to go. Take a look at the seed packet of each… but be wary because nearly every single one will say “plant after all danger of frost has past” and if you listen to that for cool flowers, you’ll be missing out on your perfect planting time. The seed packet should tell you days to maturity and when to start (ex. 3-4 weeks before last frost, 10-12 weeks before last frost, etc.). This is a guide. From there, use my posts about timing your planting/seed starting to help you: Part 1 and Part 2. For snaps who need about 10 weeks to becoming transplantable seedlings, you’ll want to shoot for a late January/early February start (if you’re in my general area). From there, they should be about big enough to harden off and transplant outside between late March/early May. They will thrive in the cool nights and increasingly warming days but can take pretty cold temps too.

If you want to learn more about cool flowers, there is the cool flowers bible conveniently titled Cool Flowers by Lisa Mason Zeigler. I refer to it all the time. Far more than any other flower book I own.

I do hope you’ll experiment with cool flowers in your own garden, if not this year surely next!

If you want to get a head start on your garden with some cool flower favorites, you might be in luck. I’ll be offering a limited number of Cut Flower Garden Collections that I carefully curated and grew here on the farm just for you to plant in your own gardens. More info to come soon. They’ll be ready for very late April/early May planting!