Dahlias are half hardy, so keep them protected from frost. Pot tubers individually between February and April and grow them on in a greenhouse or bright indoor position. Alternatively, start them outside in May, once the risk of frost has passed.
'Mercator'
Feel like a touch of Christmas in the middle to end of summer? Dahlia 'Mercator' could do that for you. This very large cactus dahlia looks a lot like a bunch of candy canes shooting out from the centre. Thin red stripes appear on the long vanilla tubular petals providing that image of the Christmas treat. They are also reminiscent of a Mercator Projection – a cylindrical map introduced during the 16th Century and used nautically because its course lines are straight. In the flower the red lines radiate straight from the centre. This flower can reach 9inches or 22,5cm, so it’s “map” will certainly give your garden direction.
The flower of Dahlia 'Mercator' can reach 9 inches or 22,5 cm, so it’s map will certainly give your garden direction.
Quantity
Plant profile
Plant calendar
For planting out later, use a snug-fitting 15–20cm pot filled with peat-free multipurpose compost. For a patio display, plant directly into a container at least 30cm wide and keep it somewhere bright and frost free until it can move outdoors.
Position the old stem facing upwards, with the tubers covered and the stem stump level with the compost. Tubers naturally vary in size and shape and may arrive without visible buds. Bent necks are usually fine if they remain firmly attached, so do not remove them.
Water after planting, then allow the compost to become almost dry before watering again while the tuber remains dormant. Once shoots and leaves are growing strongly, water more regularly, always allowing excess water to drain away.
Plant out after the last frost, once the plant is around 20–30cm tall and its roots hold the compost together. Space dahlias approximately 30–50cm apart in borders, allowing less room for compact varieties. Water thoroughly after planting.
Water regularly during active growth and deadhead or cut flowers often. Dahlias usually bloom from July or August until the first frost, although later-planted tubers may start in late August or September. In autumn, lift, clean and dry the tubers, then store them somewhere cool, dry, airy and frost free.
- Botanical name
- Dahlia 'Mercator'
- Flower colour
- Yellow, red
- Tuber size
- 1
- Established height
- 70cm-1m
- Established spread
- 30-50cm
- Growing skill
- Easy to grow
- Habit
- Upright
- Hardiness
- Half hardy
- Leaf colour
- Green
- Mouse resistant
- No
- Plant spacing
- 5 tubers per m2
- Pollinator friendly
- No
- Position
- Sheltered
- Rabbit resistant
- No
- Scented
- No
- Soil acidity
- Any
- Soil moisture
- Free draining
- Soil type
-
Loam
Sandy
Multipurpose compost
Loam-based compost - Suitable for
-
Large containers
Borders
Gravel gardens
Coastal gardens
Cottage gardens
Low maintenance gardens
Cut flower gardens - Sunlight
-
Full sun
Partial shade - Toxicity
- No report
- Years to establish
- 1st year
Expert care from
choice to delivery
Our horticulturalists prepare every bulb and plant with the utmost care. From selection to packing, each one receives expert attention before beginning its journey to your garden.