Do Dahlias Grow In Colorado – A High-Altitude Gardener’S Success

ByRimon Chowdhury Updated on

Have you ever stood in a garden center, mesmerized by the explosive, geometric beauty of dahlia tubers, only to wonder, “Could these possibly survive our wild Colorado weather?” It’s a question every local gardener asks. Our sunny days are glorious, but our late frosts, intense sun, and unpredictable hail can feel like a gauntlet for delicate flowers.

I’m here to promise you something exciting: not only can you grow dahlias in Colorado, but you can grow them spectacularly. With a few key adjustments for our unique climate, you can fill your garden with these breathtaking blooms from mid-summer until the first hard frost.

This comprehensive do dahlias grow in colorado guide will walk you through everything. We’ll cover choosing the right varieties, pinpointing the perfect planting time, mastering summer care, and even tackling the crucial task of saving your tubers for next year. Let’s get growing!

So, Do Dahlias Grow in Colorado? A Resounding Yes!

Let’s get this out of the way first: Yes, dahlias absolutely thrive here. In fact, some aspects of our climate give them a distinct advantage. Dahlias are native to the mountainous regions of Mexico, so they’re no strangers to high altitudes and significant temperature swings.

Our intense, high-altitude sunshine fuels vigorous growth and vibrant bloom colors. The cool nights we experience, even in summer, allow the plants to recover from the heat of the day, leading to stronger stems and longer-lasting flowers. The primary challenge isn’t our summer—it’s our winter.

Dahlias grow from tender tubers that cannot survive our frozen ground. This simply means we treat them as “tender perennials.” We plant them in the spring after the frost danger has passed and dig them up in the fall to store indoors. It’s one extra step, but the rewards are immeasurable.

The benefits of do dahlias grow in colorado are clear: you get a non-stop flower factory for your garden, a constant supply of incredible cut flowers for your home, and a vibrant hub for happy pollinators.

Choosing the Best Dahlia Varieties for the Centennial State

While most dahlias will perform well, setting yourself up for success starts with smart selection. With our sometimes-shorter growing season, focusing on certain characteristics can make a big difference.

Focus on Faster Bloomers

Look for varieties described as “early-blooming” or those with a shorter “days to maturity” number (often 80-90 days). This ensures you get the most out of our frost-free window. Varieties like the ‘Karma’ series or many of the collarette and anemone types tend to flower a bit earlier.

Consider Plant Size and Wind

Colorado is no stranger to gusty winds. While the giant “dinner plate” dahlias are stunning, their heavy heads can be more susceptible to snapping. If you live in a windy spot, consider focusing on varieties with smaller, 4-6 inch blooms. Ball, pompon, and waterlily types have incredibly strong stems that stand up better to the elements.

Where to Buy Quality Tubers

Your success begins with a healthy tuber. A good tuber should be firm and plump, like a small potato, with at least one visible “eye” (a small nub where the sprout will emerge). Avoid tubers that are soft, mushy, or completely dried out.

  • Local Garden Centers: A great option for seeing what you’re buying. They often carry varieties known to perform well locally.
  • Online Specialist Growers: Companies that focus solely on dahlias often have a much wider and more unique selection. Order early (in January or February) as popular varieties sell out fast!
  • Local Flower Farmers: Many Colorado flower farms sell their excess tubers in the spring. This is a fantastic way to get proven local performers and support a local business.

How to Do Dahlias Grow in Colorado: Your Planting Playbook

Timing and location are everything when it-comes to planting dahlias in our state. Follow these do dahlias grow in colorado best practices for a strong start.

When to Plant Your Tubers

The golden rule for planting dahlias in Colorado is: wait until after the last frost. For most of the Front Range, this means waiting until after Mother’s Day. If you’re in the mountains, you may need to wait until late May or even early June.

READ MORE  Dahlia Flower Growing - Your Step-By-Step Guide To A Stunning Cut

Planting too early risks having a tender sprout emerge only to be killed by a late-season snow or freeze. Patience is your best friend here. The soil should be at least 60°F (15°C). A soil thermometer is a cheap and invaluable tool for any serious gardener.

The Perfect Spot: Sun, Soil, and Shelter

Dahlias are sun worshippers. Find a location that receives at least 6 to 8 hours of direct sunlight per day. Morning sun is particularly valuable. In Colorado, the afternoon sun can be scorching, so a spot with a little late-afternoon shade can actually be beneficial, preventing wilt and stress.

They also demand well-draining soil. If you have our common heavy clay, you must amend it. Clay soil holds too much water, which is the number one cause of tuber rot. We’ll cover soil prep next!

Prepping Your Soil for Success

This is arguably the most important step for a thriving dahlia patch. Taking the time to prepare your soil before planting will pay dividends all season long.

  1. Loosen the Soil: Dig down at least 10-12 inches to loosen compacted soil, allowing roots to spread easily.
  2. Add Organic Matter: This is the secret to improving clay soil. Mix in a generous 2-4 inch layer of high-quality compost. This improves drainage, adds vital nutrients, and promotes a healthy soil ecosystem. This is a core principle of sustainable do dahlias grow in colorado gardening.
  3. Avoid High-Nitrogen Fertilizer: At planting time, you can add a small handful of a low-nitrogen fertilizer (like bone meal) to the hole. Too much nitrogen will give you big, bushy green plants but very few flowers.

The Planting Process, Step-by-Step

Don’t worry—this is the easy part!

  1. Dig a hole about 4-6 inches deep and wide enough to comfortably fit your tuber.
  2. If you plan to stake your dahlia (which you should for any variety over 3 feet tall), put the stake in the hole now, before the tuber. Driving it in later risks piercing your precious tuber.
  3. Lay the tuber horizontally in the hole with the “eye” or sprout pointing upwards. If you can’t find an eye, don’t panic! Just lay it flat, and it will find its way up.
  4. Gently backfill the hole, covering the tuber with 4-6 inches of your amended soil.
  5. Do NOT water your tuber after planting. This is a critical Colorado tip. There is enough residual moisture in the soil to get it started. Watering before you see green growth is the fastest way to rot your tuber. Wait until the first sprouts appear above the soil.

The Ultimate Colorado Dahlia Care Guide

Once your dahlias are in the ground, a little consistent care will keep them blooming their hearts out. This do dahlias grow in colorado care guide covers the essentials.

Watering Wisely in Our Dry Climate

Once your dahlias have sprouted and are actively growing, they need consistent moisture. A deep watering 2-3 times per week is much better than a shallow sprinkle every day. Use a soaker hose or drip irrigation for the most eco-friendly do dahlias grow in colorado watering method. This delivers water directly to the roots, reduces evaporation, and keeps the foliage dry, which helps prevent powdery mildew.

Feeding Your Flower Factory

Dahlias are heavy feeders. Start fertilizing them about a month after planting and continue every 3-4 weeks until early September. Use a liquid fertilizer that is low in nitrogen and high in potassium and phosphorus (the last two numbers on the N-P-K ratio). Look for a “bloom booster” or tomato fertilizer.

Staking: A Non-Negotiable Step

I can’t stress this enough: stake your dahlias! A single Colorado thunderstorm with high winds can snap an unsupported plant in seconds. For taller varieties, place a sturdy stake (like a 5-6 foot T-post) at planting time. As the plant grows, use soft garden twine to loosely tie the main stem to the stake every 12-18 inches.

Pinching and Deadheading for More Blooms

When your dahlia plant is about 12 inches tall and has 3-4 sets of leaves, perform the “pinch.” This means snipping off the top 3-4 inches of the central stalk, right above a set of leaves. It feels scary, but this encourages the plant to branch out from the base, resulting in a bushier, sturdier plant with many more flowers. For a continuous supply of blooms, you must “deadhead,” which is simply cutting off spent flowers. Cut the stem deep into the plant, just above a set of leaves, to encourage new buds to form.

Common Problems with Do Dahlias Grow in Colorado (And How to Fix Them)

Even with the best care, you might encounter a few issues. Here are some of the most common problems with do dahlias grow in colorado and how to handle them.

READ MORE  Growing Dahlias In San Francisco - Your Ultimate Fog City Flower Guide

Pests to Watch For

  • Earwigs and Slugs: These critters love to munch on tender leaves and petals, leaving ragged holes. Slug bait can be effective, or you can trap earwigs in a small container with a bit of oil and soy sauce.
  • Spider Mites: These thrive in our hot, dry conditions. You’ll see fine webbing on the undersides of leaves. A strong blast of water from the hose can dislodge them. For heavier infestations, use an insecticidal soap.

Diseases

Powdery Mildew is the most common issue, appearing as a white, dusty coating on leaves, especially later in the season when nights are cool and damp. Ensure good air circulation by giving plants enough space. You can treat it with a potassium bicarbonate or neem oil spray.

Environmental Stress

Hail is the bane of the Colorado gardener. If a hailstorm shreds your dahlia’s leaves, don’t give up on it! Clean up the debris, give it a dose of liquid fertilizer to encourage new growth, and it will often recover and still produce blooms.

The Big Decision: Overwintering Dahlia Tubers in Colorado

Because our ground freezes solid, you must dig up your dahlia tubers if you want to grow them again next year. This is the final, crucial step in our do dahlias grow in colorado tips.

Wait until after the first hard frost has blackened the foliage. This signals the tuber to go dormant for winter. Cut the stalks down to about 4-6 inches. Carefully use a pitchfork or shovel to dig around the clump, giving it a wide berth to avoid damaging the tubers. Gently lift the entire clump from the ground.

Hose off the excess dirt and let the clump dry for a day or two in a cool, sheltered place like a garage. Once dry, you can pack them for storage. Place the tubers in a cardboard box or plastic bin filled with a medium like peat moss, wood shavings, or vermiculite, ensuring the tubers aren’t touching. Store the box in a cool, dark place that stays between 40-50°F (4-10°C) all winter. An unheated basement or insulated garage is often perfect.

Frequently Asked Questions About Growing Dahlias in Colorado

Can I grow dahlias in pots in Colorado?

Absolutely! Container gardening is a great option. Choose a large pot (at least 5 gallons or 12-14 inches in diameter) with excellent drainage. Potting soil dries out much faster than garden soil in our climate, so you will need to water more frequently, possibly even daily during hot spells.

When will my dahlias start blooming?

This depends on the variety and when you planted them, but generally, you can expect the first blooms to appear in mid-to-late July. They will then continue to bloom prolifically until the first hard frost, often in October.

Are dahlias deer or rabbit resistant?

Unfortunately, no. Dahlias are quite tasty to deer and rabbits. If you have a lot of wildlife pressure in your area, you will need to protect your plants with fencing or a reliable repellent spray.

Your Colorado Dahlia Adventure Awaits!

So, do dahlias grow in Colorado? You now know the answer is a huge, bloom-filled YES! It might seem like a lot of information, but it boils down to a few key principles: plant them late, give them sun and rich soil, support them, and dig them up before winter.

The joy of walking out to your garden on a crisp August morning to see a riot of dahlia color is one of the great rewards of gardening in our beautiful state. You have the knowledge and the plan. Now go forth and grow something spectacular!

Rimon Chowdhury
Latest posts by Rimon Chowdhury (see all)

Similar Posts