Dahlias: Care, Overwintering & Feeding

Profile

Plant group

Dahlias for borders and containers

Growth & habit

Upright herbaceous stems with mostly opposite, toothed leaves. Underground swollen storage roots, not true bulbs.

Family

Aster family (Asteraceae)

Origin

The genus originates in Mexico, Central America and parts of South America; garden cultivars are bred hybrids.

Height

About 30–180 cm depending on cultivar; distinguish compact bedding and tall cutting types.

Bloom

Summer until the first frost; flower form and start vary by cultivar.

Toxicity

Not intended for eating. Plant material may irritate skin; wear gloves. Ingestion may cause digestive upset; keep away from pets.

Care calendar

Flowering / flower development

Jan
Feb
Mar
Apr
May
Jun
JulIndicative season
AugIndicative season
SepIndicative season
OctIndicative season
Nov
Dec

Summer flowers until the first frost; starting early and cultivar affect timing.

Guidance for Germany and Central Europe. Position, weather, species and cultivar shift these windows; indoor and container plants also depend on their winter conditions.

Your seasonal care plan

January

Check stored tubers for rot and severe shrivelling; keep frost-free.
February

Plan cultivars and positions; inspect damaged tubers separately.
March

Start tubers in suitable bright, frost-free conditions; identify growing points.
April

Grow young plants in good light and harden off gradually; protect from frost.
May

Plant after local frost risk ends; support tall cultivars immediately.
June

Check moisture and nutrient supply; feed growing plants according to need.
July

Remove faded flowers, adjust supports and inspect foliage for pests.
August

Maintain even root-zone moisture, cut flowers and remove diseased leaves.
September

Enjoy flowers; do not extend feeding beyond actual need.
October

After frost damages growth, lift tubers carefully, allow to dry and label.
November

Store tubers frost-free with ventilation; avoid wet material and rot.
December

Inspect stored tubers regularly; do not fertilise dormant tubers.
Planting outdoors

Months: May · Jun

Plant outdoors only after frost risk has passed.

Highlighted months are guidance, not fixed dates. Observe the plant, root ball and weather; water, feed and repot according to actual need.

Seasonal care intensity

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Seasonal guidance for Germany. Needs depend on location, weather and species. Check moisture in winter too; these markers are not a feeding schedule.

Peak care Active Reduced care

Care tips

Support tall cultivars early.
Keep roots evenly moist, not wet.
Overwinter dormant tubers frost-free.

Plant knowledge at a glance

Position, benefits & character

Pruning & growth habit

Upright herbaceous stems with mostly opposite, toothed leaves. Underground swollen storage roots, not true bulbs.

1. Remove faded flowers
Cut spent heads back to a strong pair of leaves. Distinguish buds from spent heads.
2. Autumn cutting
After foliage dies, shorten stems, lift tuber clumps carefully and label them.

Nursery forms

This overview explains nursery supply forms. It does not indicate current availability in the GREEN24 shop.

Container-grown

Common form

Available as potted plants, rooted young plants or dormant tuber clumps. Check the crown for a growing point and sound tissue.

Young plant

Common form

Available as potted plants, rooted young plants or dormant tuber clumps. Check the crown for a growing point and sound tissue.

Bare-root

Common form

Available as potted plants, rooted young plants or dormant tuber clumps. Check the crown for a growing point and sound tissue.