The illustrated growing guide

Dahlia

Dahlia pinnata hybrids

Family Asteraceae

Est. zones 8-10

Botanical illustration of Dahlia — Bulb · Dahlia pinnata hybrids

The cut-flower champion of fall — one tuber returns fifty stems when everything else quits. The dig-and-store ritual is 30 minutes for next year's hundred dollars of tubers.

Bulb

Where to buy the plant — 3 nurseries

Dahlia — a print from the Garden Blooms collection

From the print shop

Growing dahlia? Hang it.

Our Garden Blooms collection carries dahlia — Dahlia pinnata, print Nº 3, “Dahlia.”

16 designsfrom $21.99white or black groundmatte poster, unframed

Shop Garden Blooms botanical prints →

Overview

Will dahlia suit your garden, and what goes wrong.

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Will it fruit where you are?

Enter your ZIP — we look up your USDA hardiness zone (2023 map) and check it against what dahlia actually needs.

Life cyclePerennial zones 8–10, annual elsewhere

Dahlia at a glance

Life cyclePerennial zones 8–10, annual elsewhere

Mature size1-6 ft by class

PollinationOpen-centered types feed bees; dinnerplates are for you

Chill requirementNot yet established

Bloom seasonJuly - FROST — peak season is September/October

Harvest seasonNot yet established

Growth rateFast from May tubers

Common dahlia problems

Slugs (spring shoots)
Earwigs
Japanese Beetles
Spider Mites
Powdery Mildew
Tuber Rot in storage

Growing

Light, water, soil, propagation and the season’s jobs.

How to grow dahlia: light, water & soil

LightFull Sun

WaterModerate — deep soak 2-3x weekly once budded

SoilRich, well-drained · pH 6.2 - 6.8

FertilizerLow-nitrogen feed monthly from July (N = leaves, no blooms)

PruningFrost blackens tops → cut, dig tubers, dry, store in vermiculite at 40-50°F — Pinch at 12 in for branching; disbud side buds for dinnerplate size; stake anything over 3 ft AT PLANTING.

Spacing18-24 in

How to plant & propagate dahlia

PropagateOffsets, division, or bulbils

When to spray dahlia

Growing season. Slug bait at emergence; mildew late is cosmetic.

Timing only — the label is the law

This is when to watch and when a treatment is worth considering, not a recommendation to apply any product. Read and follow the product label before you spray — under federal law the label is the legal instruction, and using a pesticide against it is illegal.

Check the pre-harvest interval. Every product that’s cleared for an edible crop sets a minimum number of days between spraying and picking. Find it on the label before you spray anything you intend to eat.
Check the re-entry interval before you or anyone else works in the treated area again, and use the protective equipment the label names.
Confirm the product is registered for dahlia in your state. A product legal on one crop is not legal on all of them, and state registrations differ — your state pesticide agency or local extension office can confirm both.
Rates and mixing instructions come from the label, never from us. We don’t publish them because they differ by product and formulation.

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The year

What dahlia asks for, month by month.

The dahlia year, month by month

MonthJanFebMarAprMayJunJulAugSepOctNovDec

Bloom

What each band means

Bloom — flowers open — pollinators working, frost on blossoms is the danger.

The dahlia year as text

Jan quiet month
Feb quiet month
Mar quiet month
Apr quiet month
May quiet month
Jun quiet month
Jul bloom
Aug quiet month
Sep bloom
Oct bloom
Nov quiet month
Dec quiet month

These are the species' typical months — expect them a few weeks earlier in warm zones and later in cold ones. Watch the plant, not just the calendar.

Ecology & uses

What it does for the garden, and what it is grown for.

Dahlia in the garden system

Nectary/insectary

AttractsBees

MoistureFacultative / average

DeerBrowsed — protect young plants

OriginIntroduced

What dahlia is grown for

! Some parts toxic — see notesMildly toxic to pets

UseCutting gardens

UseFall weddings

UseTuber trading

Edibility, identification, and traditional-use notes here are general reference — not medical or veterinary advice, and not a claim that any plant treats or prevents anything. Medicinal ratings record how strongly a plant features in herbal tradition, nothing more. Never eat or dose a plant you have not positively identified. More on how to use this library.

Cultivars

Named varieties of dahlia, ruled as a catalogue.

Best dahlia varieties & cultivars

'Café au Lait' (the wedding one); 'Bishop of Llandaff' (dark leaf, single); ball types (best vase life); 'Thomas Edison'

Sources & plant ID

Where the care distinctions come from, and how the plant is filed.

Research basis

Sources behind this profile

No extension citations are attached to dahliayet. The care figures below come from the library's own catalogue rather than a traced primary source.

Plant ID

BinomialDahlia pinnata hybrids

FamilyAsteraceae

TypeBulb · Tender Perennial

USDA symbolDAPI3

OriginIntroduced

Invasive riskLow

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Where to buy

Third-party nurseries — not Story Thyme Farms.

Third-party nurseries, not Story Thyme Farms. Prices are theirs.

Story Thyme Farms may earn a small commission from these links, at no cost to you — it never changes what we recommend.

Botanical InterestsDecorative Double Blend Dahlia Seeds$2.69↗Botanical InterestsCactus Flowered Blend Dahlia Seeds$2.69↗EtsyBrowse growers↗

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Questions

Dahlia questions, answered straight.

Is dahlia safe for kids and pets?

With care. Mildly toxic to pets Site it accordingly if children or pets roam the garden. This is general reference, not medical or veterinary advice — call a vet or poison control if something has actually been eaten.

How do you propagate dahlia?

Offsets, division, or bulbils.

Elsewhere

Where dahlia sits in the library.

Grows in the same world