As the Ground Thaws in March, I'm Sowing These 8 Flower Seeds for a Head Start on Summer Color
Lots of hardy annuals are tough enough to be sown outside as soon as your soil is workable. Stockpile these seeds now, have your trowel at the ready, and watch that weather forecast!
I can’t wait to get cracking in the garden now the evenings are getting lighter and spring is just around the corner. So many flowering plants can only be sown after your last frost date – but not these tough cookies! They're tenacious enough to cope with a little cold weather and you can start seeds in the ground as soon as your soil has thawed.
All these colorful garden gems are hardy annuals, which means they’re cold-tolerant to some degree, and complete their lifecycle in a year. Because their goal is to germinate, then grow flowers to attract pollinators so they can set seed to ensure there’s another round of this game of life next year, they’re fast workers. And they really want to grow! So all you need do is give them a fair chance.
As soon as your soil thaws enough to be workable, direct-sow these hardy annual seeds where you want them to grow. It helps if the ground has warmed up a bit, so look out for the moment in your garden when those pesky weed seeds start springing up everywhere. That’s a great indicator that the soil is warm enough for these resilient plants to germinate and get off to a good start.
You’ll have to accept that there’s an element of luck involved, because if you’re hit with a lengthy blast of bad weather when the seedlings are small, they may not survive. But all these seeds are so tiny that you get hundreds in an average packet, so simply have another go once that cold blast has passed. Depending on how exposed your garden is, they’ll typically cope with a light frost. And, if a particularly hard late frost is forecast, you can always throw over some horticultural fleece, like this lightweight fabric from Amazon, to keep them cozy overnight.
As a back-up policy, I always like to start just a few seeds indoors at the same time I direct-sow outdoors. Most of these plants hate to have their roots disturbed so sow them in biodegradable pots, like these starter pots from Amazon, so you can put them straight into the ground, pot and all, in a month or two. They don’t need rich, fertile soil, so choose a seed starting mix that prioritizes drainage above nutrients, such as this mix from Amazon. Invariably, I don’t need ever these Plan B plants, and my neighbors get lucky.
Obviously, the closer you sow to your last frost date, according to your USDA zone, the better the chances of survival. And of course, germination might take a little longer. But I’m always surprised by how these plucky plants shrug off any unseasonal weather, and getting them started early means I get to enjoy their colorful petals as soon as possible. I always scatter whatever’s left in the seed packets after my last frost date, too, for a second, later flush.
So far, so easy. But the best thing about my favorite hardy annuals below? Precisely because they're annuals, they make vast quantities of seed. You can either collect and save some seed at the end of summer, or let nature do the work for you and leave the seedheads in place to self-sow. Enjoy your super-colorful summer!
Hardy Annuals to Sow Early
Ooh will you just look at the lovely hues of this corn poppy! It boasts double blooms in shades of dusky rose to a beautiful burgundy, often shot through with a smoky, silvery sheen. Each and every flower has a unique color combo, and they’re super-easy to grow. They happily self-seed, so sow these once, around a month before your last frost date, and you’ll have these pretty petals for years to come.
These painterly blooms are so dramatic for their diminutive size, and they grow so profusely, you’ll quickly have a bank of individually patterned flowers. Their filigree foliage is light and airy, so this is a great plant to squeeze into a bed as it won’t smother other growth. The shapely purple seedpods are divine, too. This isn’t quite as tough as some of the others, only hardy to -5°C, but definitely worth an early punt.
Bring a vintage palette of blush pinks, rosy reds and creamy whites to your garden with this charming annual. It’s ridiculously easy to grow and pollinators will adore it as much as you do. Tough as they come, direct sow from March and they’re quick to flower, blooming all through summer if you deadhead regularly. Centaurea cyanus petals are edible, so sprinkle a few into a salad for a pretty garnish.
A wonderful filler for bouquets as well as borders, the vibrant green colour of Ammi visnaga umbels are a fantastic foil for other flowers. Also known as Bishop’s Flower, the blooms fade to a clean white. It’s hard to believe that the tiny seeds grow into such statuesque plants, with stems reaching up to 50 inches high. It needs a little more warmth than the others to germinate, which can take up to 30 days, so be patient.
Nemophila menziesii may only grow to 4 inches tall, but its delightful saucer-shaped flowers will be noticed by every garden visitor, thanks to that bright blue hue. It’s native to North Western America and positively prefers the cold. Sow as soon as the soil can be worked but only a ⅛ inch or so deep, as the seeds need light to germinate. In warmer zones 8–10, it’s best to sow these beauties in late fall.
Iberis umbellata is a darling of a hardy annual (don’t mistake it for the perennial candytuft, Iberis sempervirens). Though it’s not as tough as others, it’s so quick and easy to grow that it’s worth sowing once you’re fairly sure you’re free of frost. If you’re lucky, you’ll have flowers by May and you can keep sowing every two or three weeks for blooms until October! This is a particularly pretty variety, and grows to 10 inches.
I’m guilty of sometimes overlooking what I think of as a basic plant – but then along comes a cultivar that shows me how wrong I am. This apricot, salmon-pink tone is simply gorgeous, and it still has all the benefits of a regular Calendula officinalis: pollinators love it, it’s useful in the veggie patch as natural pest control, and its petals are edible. Sow it as soon as your ground thaws and you’ll have blooms by June.
Here’s another corn poppy that’s far less delicate than its dainty appearance suggests. It grows a lovely mix of pink, red, white and silvery grey flowers, and the petals have a shell-like luster, hence their name. They grow as single and double blooms, too, adding to the variety, and bring a dreamy, romantic vibe to a border. These gently self-sow, too, so they’re an effortless garden addition.
