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How to Grow

10 self-seeding flowers that will re-seed on their own even if you live in a cold climate like we do here in Zone 3. Calendula, borage, cosmos, black eyed susans,

10 Flowers That Easily Self Seed In Zone 2-4

by on September 20, 2024
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There’s nothing I love more than letting the garden do the work for me. As a self proclaimed “lazy gardener” it’s such a gift to watch what new flowers (and herbs!) sprout in the Spring without having to directly sow them again. While some gardeners find self-seeding flowers a nuisance, I rejoice in them! Less work in the garden is a beautiful thing, right?

This post covers 10 self-seeding flowers that will re-seed on their own even if you live in a cold climate like we do here in Zone 3. I’ve even heard other gardeners share that some of these flowers on this list (borage specifically) will re-seed in grow zones as cold as Zone 0. How amazing is that?

*Note: As I’m editing this blog, I’m already thinking of dozens of more self-seeding flowers I could add to the list. Here’s a few that come to mind:

Settle in and take some notes on what flowers to add to your garden for next season, or on what flowers you should leave in your garden this Fall to allow Mother Nature to do her work.

Our self seeded flowers in our Zone 3 garden. Pictured: borage, dill, bee balm and poppies.

How To Get Flowers To Naturally Reseed in Your Garden Next Season

Let’s start with the how — how can you get your flowers to multiply the following season without planting more? There’s four easy things I do to ensure my annual flowers reseed in Zone 3;

First, I don’t clean up my flowers in the Fall. Instead, I leave the entire plants in the ground so the seed heads can fall to the soil to reseed. Easy as that.

Plus this saves you from doing more Fall garden clean-up, so it’s a win-win! Further more, leaving plants in your garden over Winter provides shelter for insects and pollinators.

I will also help Mother Nature along a little bit, breaking open some seed heads and patting them into the soil. That’s the second step to this and really easy to do with flowers, like poppies (pictured here) and calendula.

Next, is mulch. In the Fall, I like to put down a layer of straw mulch to protect the soil from the harsh Winter elements. I’m cautious with not laying too much mulch where my flowers are reseeding so that they don’t get smothered and/or displaced.

The final step happens in the Spring. I am cautious with weeding in these areas to ensure I don’t pull up any flowers that are germinating. You could put some stakes in the ground around the area where your flowers are reseeding to be sure not to pull them up while weeding.

And that’s it! It’s really so easy to let flowers reseed each season.

Are Self-Seeding Flowers And Perennials The Same Thing?

No, self seeding flowers and perennials are not the same thing and here’s why.

Self seeding flowers can be either perennial or annual flowers that have seed heads that die and drop to the soil at the end of the season. It’s those newly fallen seeds that will reseed the following year. This is unlike perennials as the original root of the plant is no longer living.

For annual self-seeding flowers, the plant’s lifecycle is just one growing season. For perennial self-seeding flowers, the plant’s lifecycle can go on for many years with the plant going dormant during the Winter and coming back each Spring.

Both perennial and annual flowers can reseed themselves.

10 Of The Best Self-Sowing Flowers For Northern Gardens

Alright, let’s get into the list!

Here are 10 of the easiest and best flowers that will reseed themselves each season even in cold climate gardens like Zone 2-4.

1. Calendula (Calendula officinalis)

Calendula is one of my fav hardy annuals to grow in Zone 3 not only because it will easily self-seed each season, but because of its medicinal properties. I love infusing into oil and then using on my skin throughout Winter. Plus you’ll really easily impress friends by gifting them your own homemade garden body care.

I love planting a mixed variety of calendula seeds so that I have a sea of orange and yellow as they continue to reseed.

In my garden, calendula flowers throughout most of the season. I’m often deadheading spent blooms and dropping them to the ground, meaning there are lots of seeds dropping to the soil consistently throughout the season. This leads to my calendula multiplying ten fold each year!

In my opinion, calendula is a must-grow self-seeding flower especially if you’re in a cold climate.

2. Cosmos (Cosmos bipinnatus)

I am completely in love with growing Cosmos and have let them re-seed along my garden walkway each season, resulting in these massive 5 feet tall plants as you can see above!

Cosmos are so easy to grow, heat-and drought-tolerant, making them a perfect choice for low-maintenance gardens.

Pro-Tip: Cosmos actually prefer poor to average soil, as rich soil can lead to excessive foliage and fewer blooms.

So avoid fertilizing or amending your soil where you plant your cosmos. I think this is the reason they do so well along my garden path where the soil is somewhat neglected.

3. Black-eyed Susan (Rudbeckia hirta)

We recently landscaped our front entryway with a few black eyed susan plants and wow are they ever prolific! They have self-seeded like crazy already and make for lovely cut flowers in bouquets.

Black eyed susan’s are perennials in Zone 3 so while they will reseed, the original plants will also come back each season. A win-win if you ask me.

4. Poppies (Papaver spp.)

I have let my poppy bed run wild and re-seed over the last few years, resulting in a gorgeous, overflowing raised bed of mixed poppies. This reel on my Instagram shows them off!

Fav Variety: If you’re looking for a stunning poppy to grow, try these Peony Poppies, linked here. Their frilly petals look like peonies and steal the show in bouquets.

After flowering, poppies form seed pods that release hundreds of tiny seeds, which scatter easily and lie dormant until the next season. You’ll notice your poppies will be one of the first things to sprout in the early Spring. They are extremely cold-tolerant.

5. Nigella (Nigella damascena)

Nigella is a whimsical, delicate flower that drop dozens of seeds when the pods open.

I’ve never personally grown nigella but have heard from other Zone 2-4 gardeners that it does well in cold climates and will easily reseed as long as the soil isn’t disturbed in the Spring since the seeds are quite fine and delicate.

To get your nigella to self-seed, leave the entire plants and allow the seed pods to open on their own.

6. Hollyhocks (Alcea rosea)

If you’re looking to make a statement and add some height to your garden, hollyhocks are the flower to go with. I absolutely love the cottage-feel of our hollyhocks and have watched my beds multiply with them over just a few seasons!

While technically biennials (plants that take two years to complete their life cycle), hollyhocks reseed themselves so well that they often return year after year. In fact, I’ve never had to wait two years to enjoy hollyhocks blooms here in Zone 3.

For best self-seeding success, leave the entire stalks in the ground at the end of the season and allow the seeds to disperse naturally. Then in the Fall, simply pull up the dead stalks and watch for new germination in the area.

7. Larkspur (Consolida ajacis)

Larkspur is a new flower for our garden, having just planed it this year. But already it’s thriving in our Zone 3 garden and I plan to let it reseed. It’s also a perennial hardy to Zone 3.

The above photo is actually from some larkspur plants I saw on a trip to B.C. a few years back, which inspired me to plant them in our own garden. Aren’t they just stunning?

Pro-Tip: Larkspur is cold-tolerant and prefers cool soils. try transplanting established plants in the Fall instead of Spring.

The delicate flowers on larkspur resemble miniature delphiniums and reseed readily. In fact, once established, larkspur can create a sea of blossoms in following years with very little maintenance.

8. Bachelor’s Button (Centaurea cyanus)

In my opinion, bachelor buttons are maybe one of the easiest flowers to grow! Plus they self-seed each year, so if you’re brand new to the whole flower growing thing they may just be the perfect choice for your garden.

Bachelor’s buttons, or cornflowers, are charming, old-fashioned blooms that come in shades of blue, pink, white, and purple. I love these simple, little flowers and have let them sprout throughout my veggie beds for the last few years.

For best self-seeding results, let bachelor button seed heads dry on the plant and then leave the entire plant in the ground at the end of the season to ensure reseeding.

9. Sunflowers

Sunflowers are wildly easy to grow and will reseed themselves in your garden…as long as the birds don’t eat all the seeds first.

Like the other flowers from this list, simply leave the sunflower heads on the plants to form and dry for the best chance of reseeding.

I love allowing my sunflower patch to self-seed each season since sunflower heads drop so many seeds, it usually results in the number of flowers I have each year multiplying by 100x.

10. Borage (Borago officinalis)

Borage

Last but certainly not least is one of my fav self-seeders, borage. If you’ve grown borage before then you know it really can pop-up like a weed in the garden year after year. I personally love it and use the edible flowers for garden cocktails as well as bouquets.

Borage has a deep tap root and will quickly re-seed in the Spring. The seeds are extremely tiny and fine, making it almost impossible to see them. So best practice is to leave the entire plants in the ground to die back, waiting til Spring to clean up.

As I mentioned in the intro, I’ve been told that borage will self-seed even in Zone 0. So it’s really a plant that will work for all gardeners, everywhere!

And there you have it!

Those are 10 flowers that will easily self-seed in your garden year after year even in cold climate, Northern gardens like we have here in Zone 3.

If there’s other flowers on your own lists that you’ve had success with self-seeding, please comment below! I’d love to hear them and I answer all comments.

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Latest Comments

  1. September 24, 2024

    My borage self seeds everywhere and I love it. Tried Cosmos for the first time this year and loved them, so hope they self seed as well!

    — Matt
  2. October 1, 2024

    Borage is like a weed, it’s wild!! I do love it too though so not complaining.

    — Maggie