Blossoming Beauties: 5 Summer Annuals for Your Sunny Colorado Garden

Are you ready to add a burst of vibrant color and charm to your sunny Colorado garden this summer? Look no further than these five popular annuals, each handpicked to thrive in the sunshine and liven up your outdoor space. From bold hues to delicate petals, these summer stars are sure to dazzle your senses all season long.

(Zinnia elegans)

Zinnias are the epitome of summer cheer, boasting a rainbow of hues ranging from fiery reds to sunny yellows and soft pinks. These hardy annuals thrive in full sun and well-drained soil, making them a perfect choice for beds, borders, and containers. One of the best features of zinnias is their long-lasting blooms, which attract butterflies and pollinators, adding life and movement to your garden. Whether you opt for compact varieties like ‘Profusion‘ or towering giants like ‘State Fair,’ zinnias are sure to steal the summer show with their vibrant colors and effortless charm.

(Tagetes spp.)

Marigolds are beloved for their cheerful blooms and pest-repelling properties, making them a must-have for any summer garden. These sun-loving annuals come in a variety of sizes and colors, from compact orange ‘French Marigolds‘ to tall and stately ‘African Marigolds.’ Not only do they add a bright pop of color to your garden, but they also help deter pests like aphids and nematodes, making them excellent companions for vegetables and other plants. Plus, their spicy fragrance adds an extra layer of charm to your outdoor space, making them a favorite among gardeners and pollinators alike.

(Cosmos bipinnatus)

If you’re looking for a carefree and whimsical addition to your garden, look no further than cosmos. These dainty annuals boast delicate, fern-like foliage and an abundance of daisy-like flowers that dance atop slender stems. Cosmos thrive in full sun and poor soil, making them an ideal choice for Colorado’s challenging growing conditions. Whether you choose classic white ‘Sensation‘ or vibrant ‘Sonata Red Shades,’ cosmos are sure to add a touch of ethereal beauty to your garden while attracting butterflies and beneficial insects.

(Petunia x hybrida)

Beloved by gardeners for their vibrant colors and versatility, they will thrive in Colorado’s summer temperatures. With hues ranging from delicate pastels to bold jewel tones, these annual flowers add a burst of color to any garden or container. They are low-maintenance, requiring only ample sunlight and well-drained soil to flourish. Their cascading habit makes them perfect for hanging baskets, while compact varieties are ideal for borders and edging. Additionally, petunias attract pollinators like butterflies and hummingbirds, enhancing biodiversity in the garden. With their long-lasting blooms and easy care, it’s no wonder these vibrant plants remain a staple for Colorado gardeners seeking plenty of bright summer colors.

(Verbena x hybrida)

For cascading color and continuous blooms all summer long, look no further than verbena. These trailing annuals are perfect for hanging baskets, containers, or spilling over the edges of beds and borders. Verbena’s clusters of tiny flowers come in a range of shades, from soft pastels to vibrant jewel tones, attracting butterflies and hummingbirds to your garden. Plus, verbena is heat and drought tolerant, making it an excellent choice for our sunny and arid climate.

These five popular low-maintenance annuals are sure to add beauty, color, and pollinator-friendly blooms to your summer garden. Whether you’re a seasoned gardener or just starting out, these versatile plants are guaranteed to thrive and bring joy to your outdoor space all season long.

Hardening Off Annuals


The gradual process of hardening off is a crucial one, like the slow but steady  way we brace our entry into a chilly lake in summer. Jumping in all at once is a shock to our system, but if we start by sticking a toe in and slowly working our way in, the total immersion is not nearly so stressful.

Plants need a period of time to get used to their new homes.  The adjustment period is called “hardening off.”  We recommend a hardening off period of about three to five days.  This will give the foliage tissue time to toughen up so the plants don’t go into shock.


1.   Put new plants outside in a place that is protected from sun and wind.  Make sure they get watered as needed.

2.   If nights will be cooler than 38-40 degrees, bring into the garage or house.

3.   Move the plants out a littler farther each day toward the place in which they will be growing.

4.   Leave the plants out at night unless there will be low temperatures.  They still might need covering at night if there is a drastic change in the weather.

5.   Plant on a cloudy day and they will take right off.  Using a root stimulator when planting will help.


The process above can be sped up, but it is basically the same.


The process here is somewhat different since you are acclimating your plants to hot sun and drying winds.

1.   Put plants in a cool, protected place for a day or two.

2.   Gradually move plants towards their new location over a period of three or four days.

3.   Plant in the cool of the evening or on a cloudy day.

4.   Be prepared to shade with a shingle or board until plants are settled in.

5.   Water as needed.  Always check the soil first.