Dahlia FAQs

Everything you need to know to grow beautiful dahlias with Roam Flora.

New to dahlias? Welcome! Whether this is your first tuber or you're adding to an ever-growing collection, we're here to help you grow something beautiful. Dahlias are wonderfully rewarding, and once you get the hang of them, it's hard to stop growing more!

Ordering & Shipping

When will my dahlia tubers ship?

We ship our dahlia tubers in the spring, once weather conditions are suitable and the risk of freezing during transit is sufficiently low. We can't guarantee exact shipping dates, but we'll do our best to get your order to you as soon as conditions allow.

Can I reserve items in my shopping cart?

Unfortunately, no. Adding tubers to your cart does not reserve them. All orders are processed on a first-come, first-served basis, and your tubers are only secured once checkout is successfully completed.

What happens if a tuber I ordered becomes unavailable?

On rare occasions, a tuber may become unsuitable for sale during storage or our final quality checks. If this happens, we'll email you to discuss your options. You can choose a different available variety or receive a refund for the unavailable item. We will never substitute a tuber without your approval.

What should I do when my order arrives?

Please unpack and inspect your tubers as soon as possible. Each tuber is guaranteed to arrive in excellent condition with at least one visible growth eye.

If you have concerns about the condition of a tuber, emailinfo@roamflora.ca within 10 days of delivery. Include your order number and clear photographs so we can assess the issue and help you.

Do you offer local pickup?

Yes! Local pickup is available at our Roam retail shop in Ottawa.

Roam Flora — Retail / City Shop
356 Woodroffe Avenue, Unit E, Ottawa, Ontario

You'll find us in the mini-mall behind Cadmans Bagels, near the corner of Carling Avenue and Woodroffe Avenue.

Please note that farm pickup is no longer available. Seeds may also be available to purchase at the shop when you collect your order.

Growing Dahlias

When should I plant my dahlias?

Here in the Ottawa area, dahlias are generally planted outdoors after the danger of frost has passed and the soil has warmed, typically in late May or early June. Timing varies with the weather each spring.

If you want to get a head start, you can start your tubers indoors in pots a few weeks earlier and transplant them outside once conditions are suitable. Keep young plants protected from frost.

Where should I plant my dahlias?

Dahlias love sunshine! Choose a spot that receives around 6–8 hours of direct sunlight per day. They grow best in fertile, well-draining soil with consistent moisture.

Avoid areas where water collects after rain, as soggy soil can cause tubers to rot. A little shelter from strong winds is also helpful, particularly for taller varieties.

How deep should I plant my tubers?

Plant tubers horizontally, with the crown and growth eye facing upward, approximately 4–6 inches deep. Cover with soil and leave enough room for the plant to grow.

If you're planting multiple dahlias, spacing them around 18–24 inches apart is a useful starting point, although larger varieties may need more room.

Which way up does a tuber go?

Look for the crown, where the tuber connects to the old stem. This is where the growth eyes develop. Position the crown and eyes facing upward, with the tuber body extending below.

Some tubers have very obvious eyes, while others can be tricky to read. Don't worry if yours isn't immediately obvious!

My tuber doesn't have a sprout. Is something wrong?

Not necessarily! Dahlia tubers are often sold dormant, meaning they haven't started producing visible shoots yet. A dormant tuber can still be perfectly healthy.

The growth eye is usually located near the crown, where the tuber connects to the old stem. Sprouting may take time, especially if the soil is cool.

Be patient and avoid digging up your tuber repeatedly to check on it. Consistently warm soil and good drainage are your friends.

Should I water my tubers right after planting?

If you're planting dormant tubers directly into the garden, avoid keeping the soil overly wet before shoots emerge. Cold, wet soil is one of the quickest ways to encourage rot.

Once shoots begin growing, water more regularly and increase watering as the plant develops. Dahlias need consistent moisture during active growth, especially during hot, dry weather.

If you're starting tubers in pots indoors, use a well-draining potting mix and water sparingly until growth appears.

Do dahlias need fertilizer?

Dahlias are hungry growers and appreciate fertile soil. Start with healthy soil enriched with compost, then use a balanced or bloom-oriented fertilizer according to its label as your plants grow.

Avoid excessive nitrogen, which can encourage lots of leafy growth at the expense of flowers. More fertilizer doesn't necessarily mean more blooms!

Do I need to stake my dahlias?

Many varieties benefit from staking, especially tall plants with large, heavy blooms. It's much easier to install stakes or supports at planting time than to add them once a large plant is established.

Tie stems loosely as they grow, leaving enough room for the stems to thicken. Smaller varieties may need little or no support.

When will my dahlias bloom?

Dahlias generally begin flowering in mid-to-late summer and continue until the first hard frost. The exact timing depends on the variety, when it was planted, and the growing conditions.

Starting tubers indoors can help you get an earlier start, but some varieties naturally flower sooner than others.

How do I get more flowers?

The secret is regular picking and deadheading!

Remove spent blooms before they form seeds, and harvest flowers regularly for bouquets. This encourages the plant to continue producing new flowers throughout the season.

Consistent watering, adequate sunlight, and good air circulation also help keep plants healthy and productive.

Why is my dahlia growing lots of leaves but not many flowers?

A few things could be happening:

• Not enough sun: Dahlias need plenty of direct sunlight to flower well.
• Too much nitrogen: Excessive nitrogen can encourage leafy growth rather than blooms.
• Inconsistent watering: Plants under stress may produce fewer flowers.
• Crowding: Plants competing for light and airflow may not perform as well.
• Timing: Some varieties simply take longer to begin flowering.

Give your plant time, check its growing conditions, and remember that not every variety follows the same schedule.

Cutting Flowers

When should I cut dahlias for a bouquet?

Unlike some flowers, dahlias don't continue opening much after they've been cut. Choose blooms that are fully open and feel firm, with fresh petals and no signs of fading.

The best time to harvest is early in the morning or during the cooler part of the day. Use clean, sharp snips and place the stems in water promptly.

How do I keep cut dahlias fresh?

Start with a clean vase and fresh water. Remove any foliage that would sit below the waterline, and change the water regularly.

Keep your arrangement away from direct sunlight, heating vents, and ripening fruit. Harvesting fresh, fully open blooms and keeping them hydrated will help extend their vase life.

Pests & Problems

What pests should I watch for?

Slugs and earwigs can be troublesome, particularly when plants are young or blooms are developing. Aphids, spider mites, thrips, and other insects may also appear during the season.

Check your plants regularly, especially the undersides of leaves and the growing tips. Catching problems early makes them much easier to manage.

Why are my leaves turning yellow?

Yellow leaves can have several causes, including overwatering, poor drainage, underwatering, nutrient deficiencies, or pests.

Check the soil moisture first. If the soil is constantly soggy, allow it to drain and dry slightly before watering again. If it's very dry, water deeply. Also inspect the foliage for insects or unusual markings.

A few yellowing lower leaves on a mature plant aren't always a cause for concern, but widespread yellowing deserves a closer look.

Why don't my blooms look exactly like the photos?

Dahlia colours and flower forms can vary slightly with weather, temperature, light, and the stage of the bloom. Some varieties change colour as the season progresses, and flowers on the same plant may show subtle differences.

If you believe your plant has produced a completely different variety from the one you ordered, please emailinfo@roamflora.ca during the growing season with your order number and clear photographs of the foliage and blooms. We work hard to keep every variety correctly identified, but occasionally mistakes happen.

Fall & Winter Care

Are dahlias perennial or annual plants?

Dahlias are technically tender perennials. They can grow year after year from their tubers, but they aren't reliably winter-hardy in Ottawa's climate.

You can grow them as annuals and start fresh each spring, or dig up and store your tubers over winter to grow again next year.

Do I need to dig up my tubers in the fall?

In Ottawa, we recommend lifting and storing your dahlias before the ground freezes. Dahlias don't tolerate frozen soil, and winter moisture can also cause tubers to rot.

After frost blackens the foliage, cut back the stems and carefully dig up the tuber clumps, taking care not to damage them.

How do I store my tubers over winter?

Once lifted, gently remove excess soil and allow the tubers to dry appropriately before storage. Remove damaged or rotting material, and store healthy tubers in a cool, dark location that stays above freezing.

A storage medium such as vermiculite can help manage moisture. Check your tubers periodically throughout winter for signs of shrivelling or rot. The goal is to keep them dormant without allowing them to freeze, dry out completely, or remain too wet.

Every storage space is different, so you may need to adjust your method to suit your conditions.

Can I leave my dahlias in the ground over winter?

We don't recommend relying on this in Ottawa. Our winters are generally too cold for dahlias to survive reliably in the ground, even with mulch. Digging and storing the tubers is the safer option if you want to grow them again next year.

Can I divide my tubers to grow more plants?

Yes! A healthy tuber division needs a piece of the crown with at least one viable growth eye. A tuber on its own, without an eye, will not produce a new plant.

Division is usually easiest once the eyes are visible, which is why many growers divide their stored clumps in spring before planting.

Still have questions?

We're always happy to help you along your dahlia-growing journey!

Email us atinfo@roamflora.ca with your question, and we'll do our best to point you in the right direction.

Happy growing,

The Roam Flora Team