Annuals in Denver | O'Toole's Garden Centers

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Annuals

Ask any recent newcomer to Colorado how it went when they tried to transplant their favorite flowers from back home. Colorado gardeners have learned to identify and adapt to the unique, varied climate conditions and growing seasons we find here in Colorado. Our hot summer days with intense high altitude sunlight and drying winds, combined with cool nights, can work to the gardener's advantage with proper planning. At O'Toole's Garden Centers we have 37 years of experience identifying the annuals that are perfectly suited for Colorado that will provide a dynamic blast of color to your garden this year. Here are just a few of the hundreds of annuals we carry at all three of our locations.

Pansy

Pansies are some of the hardiest, easiest and most versatile annuals available. With proper care they can bloom from spring to fall and they will often re-seed themselves the following year. Pansies bloom with the full rainbow of colors, in solid shades and in distinctive two-tone patterns called faces. Pansies are equally useful in mass plantings of color, borders, pots and hanging baskets, edgings or covers for spring bulbs.

Petunia

Petunias are the heart and soul of any annual garden. They are grown in every color under the sun, from reds and pinks, blues and purples, whites and even black! They can have spreading, mounding or trailing growth habits, which makes them suitable for just about any garden application. For sheer color, petunias are essential.

Geranium

There are several distinct varieties of this old garden favorite. Ivy geraniums have a trailing growth habit and glossy green leaves beneath showy flower clusters. Zonal Geraniums grow more upright with big masses of flowers and soft, green or two-toned leaves. Scented Geraniums have vivid foliage, dainty flowers and aromatic leaves. Regal or Martha Washington Geraniums are tall and bushy with rich and showy floral display.

Sweet Potato Vine

Sweet Potato Vines are vigorous and heat tolerant annuals grown for their dramatic foliage. Their trailing growth habit makes them the perfect “spiller” for patio pots or hanging basket. Sweet Potato Vine’s dense leaves grow in shades of green, lime, red and purple.

Spikes

Variously know as Spikes, Cabbage Palm, Cordyline or Dracaena, these easy-to-grow annuals add a great foliar accent to containers or pots. Their tall, blade-like leaves make a perfect “thriller.” Spikes come in shades of greens and purples, making them very versatile, contrasting flowering annuals.

Snapdragon

Snapdragons, with their towering spires of vibrant flowers, are a classic cut flower. They make perfect sunny borders and vertical accents as well. Though they may overwinter, their best treated as annuals. Their sprays of two-lipped blossoms bloom in reds, oranges, purples, yellows, whites and pinks.

Impatiens

Impatiens are the shade annual par excellence. Known for their almost neon purples, pinks, whites and blues, impatiens add a blast of color in the garden or containers. New Guinea Impatiens have striking foliage, elegant flowers and can take more sun than other varieties.

Begonia

Begonias are among the most popular shade-loving annuals. They provide a splash of color with vibrant foliage, showy flowers and sometimes both. Begonias bloom in a variety of colors, from reds and pinks to oranges and creamy whites. Begonias are perfect in the garden, in pots or in hanging baskets. Begonias thrive in filtered shade with rich, well-drained soil and moderate water.

Dahila

These popular and varied annuals, sometimes called African Daisies, offer a wide variety of flower forms and colors. Osteos are drought tolerant and can stand poor soil, but they look their best with well-drained, rich soil and regular irrigation. They look wonderful along driveways or paths or in borders, rock gardens and containers.

Osteospermum

These popular and varied annuals, sometimes called African Daisies, offer a wide variety of flower forms and colors. Osteos are drought tolerant and can stand poor soil, but they look their best with well-drained, rich soil and regular irrigation. They look wonderful along driveways or paths or in borders, rock gardens and containers.

Marigold

Marigolds are considered as among the easiest and most versatile flowers to grow in a garden because they tolerate most soils.

In temperate climates, seeds are sown in spring for blooms that last through the summer and into the fall.

One of the most popular and easiest to grow annuals, Marigolds add a bright splash of yellow, orange or red to the garden. These natives of Mexico and Central America love the sun and are drought tolerant.

Bacopa

Long blooming and versatile, bacopa has become an annual garden staple. Its long, trailing growth habit makes it perfect as a hanging basket or patio pot “spiller.” It blooms profusely, with cascades of little five-petal flowers in white or purple. Bacopa are fairly low maintenance and do best with a little protection from the hottest summer sun.

Alyssum

Sometimes known by its scientific name, lobularia, Sweet Alyssum blooms with masses of white, clustered flowers with a sweet fragrance. Alyssum adds a splash of color when massed in landscape, in combination with other annuals or in hanging baskets or containers.

Callibrachoa

Available in nearly every color under the sun, also called Million Bells, calibrachoa is a modern garden essential. Calibrachoa blooms with hundreds of miniature petunia-like flowers, forming a blanket of brilliant color from summer to early fall. Calibrachoa also drops its spent flower heads, so you don’t need to deadhead. Though it creates a dramatic effect anywhere in the garden, calibrachoa is most popular as a great container spiller.

Stock

Stock is an old fashioned garden staple from the Mediterranean region. Stock is known for its profusely blooming flowers and spicy-sweet aroma. Stock blooms in shades of pink, purple, white and red. It’s sweet perfume makes great cut flowers as well.

Cosmos

Cosmos are known for having maximum impact with minimal trouble. They have bright, daisy-like flowers in variety of colors and forms. Cosmos prefer the full sun and can take dry conditions and less-rich soil. They also attract butterflies and birds and make great cut flowers. The variety Cosmos atrosanguineus, or Chocolate Cosmos, has pronounced chocolate scent.

Salvia

Annual Salvias come in much more vibrant colors than their perennial cousins, bursting with vivid reds, blues and purples. They love full sun areas and their aromatic flowers attract butterflies, bees and hummingbirds. Annual salvias are equally at home on patios as they are along walkways or in flower beds.

Lobelia

Lobelia is blooms with tiny flowers of blue, white, pink or purple. It can have trailing or mounding habits, making it very versatile for container planting or in the garden. Easy to grow and relatively headache free, lobelia provides bright color from spring to summer.

Sunflower

American natives, sunflowers are grown for beauty as well as harvested for seed.

Sunflowers have big, daisy-like flower faces of bright yellow petals (and occasionally red) and brown centers that ripen into heavy heads filled with seeds.

Tall and course, Sunflowers have creeping or tuberous roots and large, bristly leaves. Some sunflowers grow to over 16 feet in height.

Zinnia

Zinnias are recommended for beginning gardeners.

Zinnias are undemanding annuals that simply need full sun, warmth, and well-drained soil rich in organic matter.

Zinnias don't like being transplanted. Sow seeds in peat pots that can be directly transplanted into the garden.

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