Dahlia 'Penhill Watermelon’

Similar to ‘Labyrinth’ in glamour and soft, curvy beauty, but more floriferous and with a good vase life. It’s one of the new on-trend must-have dahlias for the garden and vase. More
1 tuber 229333-1 £4.50
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3 tubers 229333-3 £10.95
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1 x 3 litre pot 229333-3L £10.50 Delivery late May
When in stock, please allow up to 5 days for despatch.
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This comes highly recommended from flower growers such as Rachel Siegfried (Green and Gorgeous) – it’s like ‘Labyrinth’ in glamour and soft, curvy beauty, but more floriferous and with a good vase life. It’s one of the new on-trend must-have dahlias for the garden and vase.

Our dahlias:

  • are first class, healthy tubers – the largest and best you can buy.
  • come with full planting, spacing and cultivating instructions for beginner gardeners
  • tubers should be potted up when they arrive and be kept in a light, frost-free place until the frosts are over and then be planted into the garden.

This can be gift wrapped in our exclusive hessian sack, with ribbon and a Sarah Raven gift card. You will be able to add this to your basket once you begin the checkout process. To add a gift message to your order, simply fill out the details at the delivery stage of the checkout.

Please note: only items which are showing ‘in stock’ can be gift wrapped.

Genus Dahlia
Group/Species Decorative Group

Broad and flat petals, normally bluntly pointed, with no central disc showing. Click here for more information about dahlia groups.

Variety Penhill Watermelon
Type Tender Perennial
Common Name Dahlia
Border Position Cutting Garden
Bulb Size I
Soil Type Broad Tolerance
Scent Unscented
Site Full Sun
Moisture Moist but Well-drained
Height 1.5m (5ft)
Spacing 75cm (30in)
Sowing, Seeds, Planting Plant just under the soil surface after the last frosts. Alternativley pot them up undercover March or early April in a generous pot (at least 2 litre) filled with multi-purpose potting compost. Place them in a light, frost-free place and keep the compost moist. Pinch out their growing tips when they have reached about 8" tall. They will have formed bushy plants by the time the frosts have ended and will be in flower by the beginning of July. If you don’t have anywhere to grow the potted tubers, you can put them straight into the ground when the frosts are nearly over, mulching them or protecting with a cloche or protective horticultural fleece if the foliage appears before the frosts are over, but this will delay flowering.
Care Tips Support with a stout stick, tie in every couple of weeks. In the south you can mulch deeply and overwinter them in the ground, alternatively, lift and overwinter your dahlias frost free undercover.
Flowering July - November
Vase Life Only pick dahlias in full flower. Recut the hollow stem ends under water to avoid airlocks.
Cooking Notes All dahlia flowers are edible. I use the petals scattered over salad and to decorate a range of puddings.
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
  • Sow Under Cover/Plant Indoors
  • Direct Sow/Plant Outdoors
  • Flowers/Harvest
Advice & Videos
Understanding dahlia groups

A list of the different dahlia groups, along with some classification info and an example of a variety in each group.

History of the dahlia

First discovered by Aztec Indians and used for food and medicine, this tuber has an interesting history of cultivation.

How to plant and grow dahlia tubers

Discover how to grow strong, healthy dahlias – how to plant, look after and overwinter them, and what to do with your bulbs when they arrive.

How to overwinter dahlia tubers

Sarah discusses the best options for overwintering dahlias – lifting or mulching.

Sublime dark dahlia flower arrangement

Sarah shows you how to make a gorgeous large arrangement of dahlias.

Planting narcissi bulbs with dahlias

Have a beautiful display of flowers in your garden from March to the first frosts with this simple planting technique.

New favourite dahlia arrangement

Sarah shows you how to make a quick arrangement of colourful dahlias.

Growing dahlias in pots

Sarah shows you her favourite dahlia varieties for pots, and gives you some tips on how to grow them successfully.

How to take dahlia cuttings

Watch and learn how to take dahlia cuttings – turn 1 tuber into 10.


Bulb Delivery - When in stock, please allow up to 5 days for despatch.

Click here to find out more information about our delivery rates and times.

Dahlia 'Penhill Watermelon’ reviews

* * * * * Average based on 27 reviews

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Reviewed 12th September 2019 by Lorna

Tall, strong growing plants with very attractive flowers as described. One of the better larger-flowered dahlias in my experience.

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Reviewed 6th August 2019 by Victoria

This has just started flowering and is NOTHING like the colour expected. It is a horrible mushy brownish colour which my children think should be put on the compost heap. I will definitely be moving it or even removing it for next year. Not impressed.

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Reviewed 5th August 2019 by Angela

Excellent dahlias with beautiful colours. Followed your dahlia advice to number of stems - heartbreaking! - and have strong healthy dahlias.

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Reviewed 3rd August 2019 by Graham

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Reviewed 3rd August 2019 by Jenifer

Really has the "Wow" factor, gorgeous colour

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Reviewed 2nd August 2019 by Sarah

Lovely heavy flowers, can droop with the weight

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Reviewed 2nd August 2019 by Carole

I have been growling dahlias for years and have never grown any like these.
I noticed SARAH Raven said if we liked LABYRINTH to try this. Warning, when staking, extra stakes must be included as flowers are huge. Love them!!

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Reviewed 1st August 2019 by Caroline

Fabulous! Huge plants, massive flowers, despite torrential rain and wind!

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Reviewed 1st August 2019 by Philippa

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Reviewed 31st July 2019 by Patrick

No flowers yet, so bit disappointed

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Reviewed 31st July 2019 by Miranda

Good service. Post office did not call on delivery so took another day to get them in that awful heat. Someone was also at home when they attempted to deliver. It would be good to have the option of where to leave a parcel. I don't remember seeing that.

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Reviewed 31st July 2019 by Corrie

Good quality plant, well packaged and watered

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Reviewed 31st July 2019 by Sue

Plant was unlabelled and not nearly as far on as I’d expected

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Reviewed 31st July 2019 by Juliet

Excellent service and rhizomes in good condition. However, I think I may have done something wrong in the growing process as although the plants have grown to about 24 inches and have abundant healthy green foliage there is no sign of any flowers. I started them off in pots and planted them out at the end of May in a sunny position and have kept them well watered in dry weather and fed them very so often with liquid garden feed. I would value your advice I. This matter.With many thanks

Reply from the Sarah Raven Team:

"Consumer Called needed personal info removed"

Posted 1st August 2019

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Reviewed 31st July 2019 by Gillian

Still waiting for it to flower

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Reviewed 31st July 2019 by Juliet

The tubers arrived safely and now the plant has grown well in my garden - no flowers as yet but the buds are there so I am forever hopeful.

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Reviewed 31st July 2019 by Bernard

Some of the Tubers were in a poor state and some that have been planted did not throw any shoots.

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Reviewed 31st July 2019 by Elizabeth

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Reviewed 31st July 2019 by Chris

Excellent Dahlia, good service from Sarah Raven

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Reviewed 31st July 2019 by Erica

Prompt arrival I have lots of leaf no buds yet

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Reviewed 31st July 2019 by Jayne

Good healthy growth but no sign of buds developing might get something by October!

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Reviewed 11th May 2019 by Holly

Very happy with my purchase.


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Reviewed 20th September 2018 by Angie

What a corker, it's huge and frilly and absolutely lovely. I agree with the previous review that it is much more yellow than the photo online. A great dahlia to add colour from a distance. Only drawback being it is so heavy and some stems are not strong enough to support the flower head but I will be planting it again next year.

A Beauty!

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Reviewed 20th September 2018 by Francina Hollis

The size of these dahlias are simply stunning! I particularly love the velvety, flowy petals and their wonderful hues in coral, pink, cream, yellow etc. My favourite from this year for sure!

gob smacking

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Reviewed 16th September 2018 by David Johnson Hartley

The most stunning flower i have ever seen and I have been a gardener for more than 50 years


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Reviewed 29th August 2018 by aileen robbins

I've never grown Dahlias before, so only purchased this and one other Dahlia, and WOW, I'm hooked! This particular variety is an absolute corker, almost dinner plate in size and just so stunning to look at. The flower itself last for weeks and everyone has commented on it, as it's in a pot by my front door. I cannot express just how delighted I am with it, and will definitely be purchasing more, so much so that I've already invested in a small greenhouse to assist me. Thank you so much


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Reviewed 27th June 2018 by Stevie Gavin

This is an incredible size, much bigger than i expected, very pretty colour although has much more of a creamy/yellow centre than the image above. Its a real talking point in the garden.