White Onesta Dahlia Tubers

• Variety: White Onesta
• Type: Decorative (waterlily form)
• Colour: White with soft greenish-yellow centres
• Flower size: 10 to 15cm across
• Height: 90cm
• Spread: 50cm
• Flowering: July to October
• Cutting: Yes. Long-lasting in a vase, prolific flower production
• 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

White Onesta: A White Dahlia with a Fresh Green Heart

White Onesta sits somewhere between a decorative and a waterlily in form. The flowers are a clean white with soft greenish-yellow centres that give each bloom a fresh, dewy quality, as if it's just opened. At 10 to 15cm across, the blooms are generous without being overwhelming, and the plant produces them in quantity all summer.

At 90cm with a compact 50cm spread, it's manageable in the middle of a border or in a large pot. The habit is neat and the flowering is prolific. It's one of those dahlias that just keeps going without asking for much in return: feed, water, deadhead, and it'll reward you from July to October.

The green-centred white colour makes it a natural for pastel schemes and white gardens, but it also works as a calming neutral among bolder dahlias. In a vase, the blooms last well and the subtle green centres add a freshness that pure-white varieties lack.

Placing White Onesta

White with green centres suits gentle, romantic schemes. Plant alongside Gerrie Hoek (shell pink waterlily, 120cm behind) and Cafe au Lait (milky coffee dinnerplate) for a soft palette that runs from white through pink to warm neutral. For contrast, the near-black of Dark Spirit (90cm, same height) makes the white sing. Grasses like Pennisetum villosum (feathertop grass) and white Veronicastrum provide a tranquil backdrop.

Why Ashridge?

Our dahlia tubers are Dutch first-class quality, imported direct and hand-graded. We discard 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 human support from the team in Somerset if anything isn't right. Browse our full decorative dahlia range or the complete dahlia collection.

Frequently Asked Questions

Is White Onesta a waterlily or a decorative dahlia?

It's catalogued as a decorative but the flower form leans towards waterlily, with broad, overlapping petals arranged in a relatively flat, open shape. The distinction matters less than the effect: elegant, understated, and easier to blend into mixed plantings than a fully double ball or pompous decorative. Our dahlia types guide explains the classifications.

Will White Onesta grow in a pot?

At 90cm with a compact spread, it's well suited to containers. Use a pot at least 30cm across and deep, feed fortnightly from June, and water regularly. It may need a light stake in an exposed spot. Our container guide has the detail.

What makes the centres green?

Newly opened blooms show greenish-yellow centres before the innermost petals fully develop. The green fades to soft cream as each flower matures, but since the plant produces new flowers continuously, you'll always have some fresh blooms with that distinctive green heart alongside older, fully white ones.

Is White Onesta good for cutting?

Very. The prolific flowering means you can cut generously without depleting the garden display. The blooms last well in water, and the green-centred whites add a fresh note to arrangements. They work particularly well mixed with deeper-coloured dahlias or with garden roses in similar soft tones. Only pick fully open blooms.

How do I keep White Onesta flowering all summer?

Deadhead regularly, feed fortnightly with a liquid fertiliser from June, and water in dry spells. That's the formula for every dahlia, and White Onesta is no exception. The more you cut, the more it flowers. Full seasonal care is in our dahlia growing guide.