Tartan Dahlia Tubers

• Variety: Tartan
• Type: Decorative (dinnerplate)
• Colour: Blackcurrant-purple and white, sharply bicoloured
• Flower size: 15 to 20cm across
• Height: 110cm
• Spread: 70cm
• Flowering: July to first frosts
• Cutting: Yes. Strong stems, dramatic in arrangements
• RHS AGM: No
• Sold as: Single tubers, hand-graded, Dutch first-class quality
• Plant outdoors: March to July, when soil reaches 15°C (typically May in most of the UK)
• Delivered: From March. Collection from Castle Cary also available

Dahlia Tartan: The Boldest Bicolour in the Border

Some dahlias are subtle. Tartan is not one of them. The flowers are a sharp, high-contrast split of blackcurrant-purple and bright white, with long wavy petals that swirl the two colours together like a fabric pattern. At 15 to 20cm across, these are dinnerplate-sized blooms on a 110cm plant, and they're not trying to be quiet about it.

The purple is deep and rich, almost black towards the centre, and the white is clean and bright. The ratio shifts from flower to flower. Some blooms are mostly dark with white tips, others more evenly split. The overall effect across a plant is striking from twenty metres away, which is either exactly what you want or too much, depending on your taste. There isn't really a middle ground with Tartan.

Stems are strong enough for cutting, and the flowers last well in water. It needs staking at 110cm, but any tall dinnerplate dahlia does. Fresh green foliage provides a clean backdrop for the dramatic flowers.

Placing Tartan in a Scheme

The trick with Tartan is to give it simple neighbours. The bicolour pattern is already doing a lot of visual work, so anything too busy alongside will compete. A pure white dahlia with a quieter flower form is the natural partner: White Swan (white decorative, 120cm) or Boom Boom White (white ball, tight spheres that give structural contrast). For a moody scheme, the deep burgundy of Dark Spirit picks up Tartan's purple tones without adding another pattern. Ornamental grasses are the right softener here: Pennisetum with fluffy seedheads brings a meadow feel that calms everything down.

Why Ashridge?

Our dahlia tubers are Dutch first-class quality, imported direct and hand-graded. We reject undersized tubers so you get a clump with viable eyes, ready to grow. Delivered by next-day courier from March, with our one-year plant guarantee, Feefo Platinum Service Award, and gardeners in Somerset on the end of the phone. Browse our full decorative dahlia range or the complete dahlia collection.

Frequently Asked Questions

Is Tartan similar to Cafe au Lait Twist?

Both are bicoloured dinnerplates, but the effect is completely different. Cafe au Lait Twist has soft raspberry streaks over cream, romantic and variable. Tartan is a hard, high-contrast split of blackcurrant and white, bold and graphic. Twist suits a wedding table. Tartan suits someone who likes their garden to have a bit of swagger.

Will Tartan grow in a pot?

At 110cm with flowers up to 20cm across, Tartan is really too big for a container. It'll be top-heavy, constantly thirsty, and the flowers will catch wind. Grow it in deep border soil with proper staking. If you want a bicoloured dahlia for a pot, Checkers (burgundy and white, more compact) is a better choice. Our pots guide covers what works in containers.

How do I stop the flowers getting battered by rain?

You can't, really. Large flat-petalled decorative dahlias like Tartan hold water in their blooms, and a heavy downpour will damage open flowers. Staking helps stop stems snapping under the weight. Picking flowers before forecast rain and enjoying them indoors is the pragmatic answer. The plant will produce more. If rain is a constant problem in your garden, ball or cactus types like Ariston shed water far better.

Is Tartan good for cutting?

The flowers are dramatic in a vase and the stems are strong enough. The bicolour pattern makes each bloom a talking point. Cut only fully open flowers, early in the morning. Condition stems in hot water for an hour. Expect four to five days of vase life. The large heads drink a lot of water, so keep the vase topped up.

When should I plant Tartan dahlia tubers?

Plant outdoors from March to July, but the soil needs to be at least 15°C, which in most of the UK means waiting until May. You can start tubers indoors from March in pots of damp compost to get a head start. Our starting dahlia tubers in spring guide explains the process.