12 Flower Seeds to Sow in April for a Garden That Blooms All Summer and Into Early Fall

How to fill in your flower beds and borders with generous, non-stop blooms through summer and into fall? Easy, sow annuals (and some perennials) in April and your garden will fill with colorful blossoms for months on end!

Yes, many annuals bloom virtually all their lives, attracting butterflies and pollinators to your green haven – some are very sweetly scented as well, and April may be your last chance to sow them in your garden.

To be honest, it depends on where you live. If you garden in a cold region (like USDA zone 5 and below), you will have time till May, but if you are in a warm place, it’s really time to hurry up.

Some perennials too are very generous with their blooms through the summer season, and I find that a mix of both adds texture and variety to flower beds, borders and even wild prairies!

But when exactly should you sow them? Is your garden ready? The soil itself will tell you; when it is steadily above 60°F (16°C), your seeds will feel warm enough to germinate. But again, don’t wait too long, because if it reaches 85 to 90°F (29 to 32°C), then it will be too hot for them, and your garden will remain flowerless and empty…

But which varieties to choose, to make sure your garden literally explodes with flowers and colors all through summer? Let’s see some classic long bloomers now!

1. Zinnia (Zinnia elegans)

Why would I definitely sow zinnias in my garden in April? Because the bloom incessantly from June till frost! But this is not the only reason… These annuals are super easy to grow, they require little care and they are very healthy – they will only catch diseases if you grow them in very humid places and soil. So, they are perfect for beginners and if you don’t have too much time for gardening.

What’s more, their blooms are come in bright colors, like the shocking pink ‘Royal Purple’ or delicate ones, like ‘Raspberry Limeade’, lime yellow with touches of green. On top of that, the blooms can be fully pom-pom double, like the snow white ‘Purity’ or single, like ‘Scarlet Flame’.

To the wide range of shapes and colors that zinnia offers you, you will also get rich and dense foliage. In fact, you need to sow them quite apart, 6 to 18 inches (15 to 45 cm) depending on the variety, ¼ inch deep (0.5 cm) and in full Sun – then you can almost forget about them, just basic maintenance and they will regale you with blooms for months. Just behead the spent flowers.

2. Verbena (Verbena peruviana, Verbena X hybrida, Verbena canadensis)

Add charm to your garden from may till frost by sowing verbena in April! Yes, this annual will start flowering in about one month and keep going forever…

It comes in many sizes, from 6 inches tall (15 cm) to 6 feet (1.8 meters)! So, you can grow it in containers, flower beds or even tall borders. Drought tolerant and suitable to any soil type, it is a very easy annual to grow as well – and one of the few that bloom in part shade.

But despite being so sturdy, it is extremely elegant, with round clusters of little flowers in pink, purple, white and red shades. Some variety even give you two colors per inflorescence, like ‘Lanai Peach’ (pale pink and rose), or multi-colored blossoms, like ‘Superbena Sparkling Ruby’ (white to magenta).

Finally, you can also get trailing varieties (Verbena canadensis), which you can use to drape pots and hanging baskets, or as ground cover.

Sow it ¼ inch deep (0.5 cm) and 12 to 18 inches apart (30 to 45 cm) and enjoy its blooms till the end of the season.

3. Echinacea (Echinacea purpurea)

Another classic marathon bloomer, but this time a perennial, is echinacea, A.K.A. coneflower. Its large blooms will fill your garden with energy and pollinators from June to at least September, or beyond in warm climates.

And don’t worry if you live in a cold country, because this is a very cold hardy perennial, down to USDA zone 3. At first, it will form a basal rosette of large leaves at the base, then you will see long stems (24 to 60 inches tall, or 60 to 150 cm!) grow up and up, till the buds appear and then open, revealing a dark cone shaped center, surrounded by iconic daisy like ray petals.

Yet another variety that will survive and bloom no matter what, super easy to grow and ideal for beginners, coneflower comes in warm colors and white, from the classic rose pink ‘Ruby Star’ to crazy shapes, like ‘Double Scoop Cranberry’ that looks like an anemone-flowered dahlia, with a round pom-pom of small blooms instead of the cone in the center.

Surface-sow them in full Sun at a distance of 12 to 18 inches (30 to 45 cm), sit back, relax and enjoy the spectacle.

4. Candle Larkspur (Delphinium elatum)

What about if you want to add a vertical accent to your beds or borders through the summer months? I have the answer for you: sow candle larkspur (delphinium) in April!

This perennial will give you long spikes of blooms from June to August, growing up to 8 feet tall (2.4 meters), unless you pick a dwarf variety (3 to 4 feet tall, or 90 to 120 cm). And this towering display will rise up above a dense basal tuft of wide leaves in deep green, like a natural bouquet.

I’ve picked another super easy and “safe” plant to grow, which tolerates almost any soil type (apart from heavy clay) but with an added bonus: it is a magnet for butterflies and hummingbirds as well!

What’s more it can add very vibrant shades of blue to violet to your summer garden, a color range which is not very common to get in this season. The deep purple ‘Faust’ cultivar, winner of the Royal Horticultural Society Award of Gardeen Merit may be the most famous cultivar of all, but if you have a moon garden, you could pick the snow white ‘Jill Curley’.

Sow it in full Sun, only 1/8 inch deep (0.3 cm) and 16 to 20 inches apart (40 to 60 cm), and soon, its spikes will rise up to reach the sky.

5. Moss Rose (Portulaca grandiflora)

How about for small places? There’s a relative of the humble purslane (Portulaca oleracea), which grows even through tarmac, that you can easily grow: moss rose!

A semi-succulent annual you can sow in April and it will just keep blooming from May/June till frost – literally non-stop. Sun loving but drought tolerant, moss rose is so called because its double varieties look like little roses indeed – well, not so little, up to 1.5 inches across (4.0 cm).

Only 3 to 6 inches tall (8 to 15 cm), moss rose has a spread of 10 to 20 inches (25 to 50 cm), with a draping habit, so it is ideal for border fronts, rock gardens, ground cover or edges. It even naturalizes in the right conditions, so you won’t need to sow it again.

I like to get a sowing mix packet, which is the easiest and most fun option, or you could pick a shade that suits your garden, with single or double blooms. Whichever you choose, its blooms with shine on top of the finely textured emerald green leaves till the end of the season.

Just scatter the tiny seeds on top of the soil and lightly press it, as it grows, you can thin it out to 6 to 12 inches (15 to 30 cm) – and use the extra plants to fill in containers.

6. Sweet Alyssum (Lobularia maritima)

Let’s meet another small beauty that definitely punches above its weight – or height in this case: sweet alyssum. Only about 6 to 8 inches tall (15 to 20 cm) and 10 to 12 inches in spread (25 to 30 cm), this little annual will flower from May to October or November.

If you sow it in April, you will see its first blooms in early June though – still its globular clusters packed with rounded flowers will attract butterflies, bees and even birds to your garden – even if you only have a small yard.

Drought tolerant and fragrant, it is very low maintenance (you don’t even need to deadhead it!) and it comes in white, like the famous ‘Snow Princess’ but also in apricot, salmon, lemon, red and purple.

It prefers morning sunshine and afternoon shade, so, sow it in full Sun or part shade. Scatter the seeds on the soil 8 to 10 inches apart (20 to 25 cm), gently press them, water and wait for the results!

7. Cosmos (Cosmos bipinnatus)

If you are looking for light elegance through summer, then cosmos is the annual for you. Flowering generously from June to October, it will offer you broad, paper thin and fringed petals in shades from white to pink, purplish and red with small golden centers.

But don’t be deceived by its ephemeral elegance, the blooms can be 4 inches (10 cm) across! And in fact, pollinators and hummingbirds won’t be fooled, and they will flock to your garden.

The green bush of thinly cut leaves underneath forms an intriguing backdrop for its long-lasting floral display, making it ideal to bring a touch of class to natural looking borders.

Sow cosmos 1/8 to 1/4 inch deep (approximately 0.3 to 0.6 inches) and 12 to 18 inches apart (30 to 45 cm) in full Sun, and water it regularly, in your garden or in containers as well.

8. Globe Amaranth (Gomphrena spp.)

If you like spherical flowers, you will love globe amaranth! And so will pollinators… And if you sow it in April, it will bloom from June till frost.

Growing to 6-24 inches tall (15-60 cm), this annual is very easy to grow and low maintenance, so perfect for amateurs and beginners, but loved like experts too, like me.

Available in white, pink, red, rose, purple and now also orangish, it is perfect for hot summers, as it is heat and drought tolerant. What’s more, globe amaranth grows in any type of soil, including heavy clay, so whichever your garden’s conditions it will fill it with lots of flowers.

Each “bloom” is actually a globular inflorescence with little tubular shaped florets, perfect for butterflies. They grow on broad, lance shaped leaves, and each “ball” is 1 to 1.6 inches (2.5 to 4 cm). But it’s the overall effect that’s breath-taking.

Sow it 1/8 to ¼ inches deep (0.3 to 0.6 cm) and 12 to 18 inches apart (30 to 45 cm) in full Sun, and in a few weeks your garden will fill with colors and pollinators.

9. Yarrow (Achillea millefolium)

On to a totally different bloom shape: take aa look at yarrow… Its clusters are round but almost flat, and they are perfect “landing pads” for pollinators, all the way from June to September, as long as you sow it in April or May at the latest.

Up to 4 inches wide (10 cm) these clusters of hundreds of florets come in red, like ‘Sassy Summer Sangria’ golden yellow, white and pink, but now you can also find other shades, like the coral ‘Sassy Summer Sunset’.

Whichever color you choose, yarrow is a super low maintenance, drought and heat tolerant perennial that never disappoints.

It is ideal for borders, as it grows to 2 to 4 feet tall (60 to 120 cm), but also wild prairies and cottage gardens, thanks to is very natural look, also enhanced by the super fine foliage that accompanies the long blooms.

Surface sow yarrow in full Sun 12 to 18 inches apart (30 to 45 cm) and enjoy its blooms till fall.

10. Pot Marigold (Calendula officinalis)

You won’t just get long-lasting flowers if you sow pot marigold in April, you will also keep mosquitoes and pests away (in your vegetable garden too)!

Super easy to grow in full Sun or part shade, pot marigold will only require basic care and beheading to keep giving you new flowers from May till the first frost! And this drought tolerant marathon bloomer is suitable to many spaces, from containers to formal gardens, for edging and mass planting or even ground cover.

In fact, it is also fairly compact (1 to 2 feet tall and wide, or 30 to 60 cm), but tough.

You can get it in warm shades from off white to red via golden yellow and orange, in single and double flowers. For a very striking effect I would suggest ‘Neon’ with shiny orange to reddish petals, but you can also get a romantic and delicate effect with the pinkish ‘Orange Flash’.

And to obtain all this, all you need to do it to sow pot marigold ¼ to ½ inch deep (0.5 to 1.0 cm) and 8 to 12 inches apart (20 to 30 cm) in your garden.

11. Nasturtium (Tropaeolum majus)

Exotic looking (and fully edible), nasturtium is grown as an annual all over the world, and it will bloom from June to at least October – but I have seen it in flower in winter too in hot countries.

And what will you get for little effort in April? To start with a carpet of trailing and crawling tender looking round leaves (excellent ground cover and rock gardens). On top of them lots of funnel shaped blooms that open to a disc of about 1.5 inches across (4.0 cm).

The most common type has orange to reddish blooms and pale green, even bluish foliage, but if you want some striking varieties… ‘Black Velvet’ has very deep, indeed velvety, purple flowers and bright green leaves. On the contrary, ‘Empress of India’ has energetic red-orangish blossoms and almost black leaves!

But you can choose other varieties, in all warm shades. But keep in mind that while it only grows to 12 inches tall (30 cm), it can spread to 10 feet wide (3.0 meter) – though it is usually about 3, or a meter.

Sow nasturtium ½ to 1 inch deep (0.5 to 2.o cm) and 10 to 12 inches apart (25 to 30 cm) for a dense effect – and only once, because it self-seeds!

12. Love-in-a Mist (Nigella damascena)

And the final annual I have to propose to you mixes elegance with striking sculptural qualities: love-in-a mist, which blooms all through summer.

In fact, look at nigella from afar, and all you will see is a light, lace like clump of leaves, like a cobweb, dotted with blooms that look a bit like cornflowers. They can be white, like ‘Miss Jekyll Alba’, or blue, even intense, like ‘Miss Jekyll dark Blue’. And they look round…

But get closer and you will see that the 1.5-inch heads (4.0 cm) are formed by two rows of pointed petals that look like stars, and they are decorated by a set of thin pointed and cut sepals, that look like rays.

Despite its elegant look, love-in-a-mist is ideal for beginners, because it is low maintenance and perfect for naturalistic border fronts or beds, but even containers, as it only grows too 2 feet tall (60 cm).

Find a sunny spot this April, sow the seeds 1/8 to ¼ inches deep (0.3 to 0.6 cm) and 8 to 9 inches apart (20 to 22 cm) and enjoy!