Growing Dahlias in Every Climate: What Matters Most

As California’s largest dahlia tuber supplier, we are often asked by customers across the state—and well beyond—whether dahlias will grow successfully in their particular climate. Gardeners in Sacramento wonder how dahlias will handle summer heat and humidity compared to the cool, foggy Mendocino Coast. Southern California growers ask whether dahlias can thrive in hotter, drier conditions. And beyond California, we regularly ship tubers to gardeners growing beautiful dahlias in places as varied as Arizona and Texas; Georgia and Mississippi; and Alaska and Maine.

The short answer is reassuring:  Dahlias will thrive in all of these climates.

At EarthSpoke Farms, our experience—both on our own fields and through our customers nationwide—has led us to a simple conclusion: nearly all dahlia cultivars can perform well in nearly any climate when the fundamentals of care are done right. Climate matters, of course, but good growing practices matter far more.

We believe it makes sense to start with those core practices, because they set gardeners up for success regardless of which cultivars they choose.

Foundational Growing Practices That Matter Everywhere

Across climates, the most successful dahlia growers tend to focus on the same essentials.

• Sunlight and Airflow.  Dahlias perform best with abundant sun and room to breathe. In warm or hot climates, morning sun followed by light afternoon shade can help prevent heat stress and sun scorch, while good airflow—supported by thoughtful spacing and site selection—reduces humidity around leaves and flowers, helping to limit mildew and other fungal issues. Planting dahlias 12 to 18 inches apart typically provides sufficient airflow.
• Watering with Intention.  Dahlias prefer deep, consistent watering rather than frequent shallow watering. In hot or arid climates, this may mean watering more deeply but less often. In humid regions, careful attention to soil moisture helps prevent rot and disease.  We water our dahlias through a drip system for 45 minutes at a time once every four days – hotter climates will require watering every two to three days.  Other farms prefer overhead watering, so you cannot go wrong with either approach. 
• Excellent Drainage.  This is non-negotiable. Whether you garden in heavy clay, sandy soil, or coastal loam, dahlias perform best when excess water can move away from the tubers. In clay soils, drainage can be improved by incorporating organic matter such as compost or well-rotted manure to create better soil structure, planting in raised beds or mounded rows to lift tubers above saturated ground, and avoiding low spots where water naturally collects. Amended soil, improved structure over time, and thoughtful site selection make a tremendous difference.
• Healthy Soil.  Dahlias are heavy feeders, but they respond best to balanced fertility. Building soil with organic matter, providing steady nutrition, and avoiding excessive nitrogen will encourage strong plants and abundant blooms rather than lush foliage alone (dial back nitrogen when buds begin to form). 
• Heat Management.  Mulching—by applying a layer of organic material such as straw, compost, leaf mold, or wood chips over the soil surface—helps moderate soil temperature, retain moisture, and reduce evaporation, which is especially valuable during hot or dry periods.  In particularly hot climates, consider watering early in the day and providing shade during extreme heat to help plants continue blooming through the toughest parts of summer. Afternoon shade can be provided by situating dahlias near taller plants, using shade cloth during peak heat, or taking advantage of structures like fences or trellises that soften late-day sun without blocking morning light.

These practices are not cultivar‑specific. They are the foundation that allows any dahlia to do what it was bred to do.

Learning from Hot and Humid Climates

While we believe care practices matter most, it is still useful to look at real‑world data from challenging environments. The Georgia Dahlia Society has helpfully documented cultivars that perform well in hot, humid conditions—a climate that can place real stress on dahlias. Georgia’s growing conditions may differ from your conditions, yet their observations provide valuable insight for growers everywhere.

Our own analysis of the Georgia Dahlia Society data, along with discussion among growers in the dahlia community, suggests two patterns that are worth noting—especially for newer growers:

• Bloom Size.  Small to medium blooms tend to fare better in sustained heat and humidity. As a general guide, blooms up to six to eight inches are often more resilient than very large or dinner‑plate types.
• Flower Form.  Certain forms appear to be more forgiving under stress. Ball and mini-ball forms, in particular, tend to hold up well, perhaps because their tight, self-supporting shape slows moisture loss in hot conditions (fewer thin edges are exposed to sun and susceptible to evaporation).  In general, the more wispy or open the petal structure, the more fragile the bloom can be under challenging conditions.

It’s important to note that these same traits—smaller bloom size and simpler forms—often correlate with cultivars that are simply easier to grow overall, regardless of climate.  In our foggy and cool climate, the morning dew or afternoon misting can weigh down extra-large decorative blooms in ways that present their own challenges.   

A Starting Point, Not a Limitation

For beginning dahlia growers, starting with cultivars known to be resilient can build confidence and early success. From there, many gardeners naturally branch out into more complex blooms and forms.

That said, starting “small” is not required. Most dahlias will grow just fine in most places if the care instructions are followed. Dahlia cultivar choice can help, but good cultivation practices matter far more.

Cultivars with a Track Record in Heat and Humidity

For gardeners interested in cultivars that have performed well in hot and humid conditions, here are several cultivars that we sell, which are noted by the Georgia Dahlia Society or discussed within the broader dahlia community as relatively easy to grow:

• Bloomquist Alan
• Bloomquist Dawn
• Bloomquist Jean
• Bloomquist Mojo
• Bloomquist Tory P
• Cornel
• Crichton Honey
• Duet
• Ferncliff Copper
• Gitts Attention
• Hamari Gold
• Hamilton Lillian
• Jessie G
• Jomanda
• Just Peachy
• L’Ancresse
• Magic Moment
• Mingus Wesley
• Otto’s Thrill
• Penhill Watermelon
• Rip City
• Robann Royal
• Rose Toscano
• Valley Porcupine
• White Nettie

And here is the selection of small and medium ball and mini-ball dahlias that we sell:

• 20th Ave Memory
• 20th Ave Tradition
• Bloomquist Champion
• Bloomquist Crave
• Bloomquist Darrell
• Bloomquist Refreshing
• Bloomquist Wonderful
• Blyton Softer Gleam
• Brown Sugar
• Caitlin's Joy
• Camano Zoe
• Clearview Peachy
• Copper Boy
• Cornel
• Cornel Bronze
• Creamy
• Crichton Honey
• Ferncliff Rusty
• Hy Suntan
• Isabel
• Jessie G
• Jowey Mirella
• Jowey Nicky
• Jowey Paula
• Jowey Winnie
• Julio
• L’Ancresse
• Linda's Baby
• Lipoma
• MM Buttercream
• Orsett Beauty
• Pink Pearl
• Robann Royal
• Robin Hood
• Rosemary Dawn
• Skipley Moonglow
• Valley Rust Bucket
• White Nettie

Our Takeaway

Climate matters, but it does not define what you can grow. With thoughtful site selection, good soil, consistent care, and attention to your local conditions, dahlias will reward gardeners in nearly every corner of the country. Our goal at EarthSpoke Farms is to help you succeed—whether you’re gardening in coastal fog, summer heat, southern humidity, or northern cold.

If you focus on the fundamentals, the dahlias really will do the rest.