Dahlia 'Blue Boy'

decorative dahlia tuber

4 5 1 star 1 star 1 star 1 star 1 star (6 reviews) Write review
1 tuber £4.99
in stock (shipped within 2-4 working days)
3 tubers £14.97 £12.00
in stock (shipped within 2-4 working days)
Quantity 1 Plus Minus
Buy Dahlia 'Blue Boy' decorative dahlia tuber: Great for cutting

  • Position: full sun
  • Soil: fertile, humus-rich soil
  • Rate of growth: average
  • Flowering period: July to September
  • Hardiness: half hardy (may need winter protection)

    Well-formed lilac-pink flowers provide colour in the border for many months from midsummer. For an outstanding display mix it with most shades of pink or purple, as well as silvers and blues.

  • Garden care: Dahlia tubers can be planted outside after frost, or started off in pots under glass in late winter to early spring. Plant them horizontally approximately 12cm deep, making sure the ‘eyes’ are uppermost. Allow enough room between each tuber so the plants can grow and spread to their full size without being overcrowded. While in growth, provide a high-nitrogen liquid feed each week in June, then a high-potash fertiliser each week from July to September. Stake with canes or brushwood if it becomes necessary. In mild areas, leave them in situ over winter, but protect the crown with a generous layer of dry mulch. In colder areas, carefully lift and clean the tubers once the first frosts have blackened the foliage and allow them to dry naturally indoors. Then place the dry tubers in a shallow tray, just covered with slightly moist potting compost, sand or vermiculite and store in a frost-free place until planting out again.

  • CAUTION do not eat ornamental bulbs
Delivery options
  • Bulb orders (dispatched separately)
more info

Eventual height & spread

Masses of flowers


Was exactly as per the pictures, masses of pale mauve, long lasting flowers until the first frosts, multiple stems, needed a bit of staking, but it's growing habit was good with stems supporting the flowers properly. It grew taller than the advertised height. Lovely plants.

In the garden



My favourite dahlia. Masses of flowers that stay upright.


I failed to lift the tubers after the last frost but mulched it generously and am now waiting for green shoots to appear! Not a great fan of cut flowers indoors as prefer to see them in my garden. However, residents of a local care home just love them - and no earwigs to upset their enjoyment.

Moira bus





Beautiful flowers.Turned out just like the picture on the sitel. Flower heads were big and abundant so lots for my vases. Easy to grow too.




No needit's a perennial


Due to ground conditions (nearby conifer) I planted in large pots or as far away from roots as I could but the plants were weak due also to pm only sunlight. This year I'm planting in a more favourably sited bed provided they have survived the winter.


Frimley Surrey


A blue beast of a dahlia!


This is the dahlia that dominated my boarders, it grew to a good 5-6ft in height and was never not crowned with amazing blue/purple blooms. There stems werent the longest but they last ages in a vase, it also produced so many main stems it was excellent to propagate from.

dahlia ben

newcastle under lyme


Nice pale blue


Nice soft blue Blend well with other flowers.





4.5 6


Cottage garden

The traditional cottage garden was an intensive, yet carefree mixture of fruit, vegetables, herbs and flowers all crowded into a tiny space. Today, this informal charm can be recreated using modern varieties that largely take care of themselves around an

Read full article

Get more flowers

Deadheading will prevent them setting seed and so use their energy producing a further flush of blooms later on. Plants that respond well to deadheading include annuals such as Ageratum, Alyssum, Antirrhinum, Calendula, Centaurea, Cosmos, Dahlia, foxglove

Read full article

How to overwinter tender perennials

Tender perennials, such as pelargoniums, fuchsias, osteospermums and marguerites look great all summer, but unless they are given protection from the harsh winter weather, they will need to be replaced each spring. If you can do this, they will last for y

Read full article

Flowers for the cutting garden

At some stage in June, your garden will be a glorious affair full of scent and soft flower. Placing a posy from the garden, close to a family hub like the kitchen table, unites your home and garden as effectively as having a huge picture window. You don’t

Read full article

Simple but stylish protection

If rabbits, deer, squirrels or cats devour or scratch up your plants these wire mesh protectors will give them time to get established. The pyramid-shaped 'Rabbit Proof Cloche' and dome-shaped 'Squirrel Proof Cloche'

Read full article

The versatile Dahlia

Come March even the most reluctant fair weather gardener is sure to be lured outside by spring sunshine and brighter light. There's plenty to do in the borders, especially after this winter's deluge, and every dry day is a chance to tidy, weed, dig or s

Read full article

Overwintering dahlias, cannas and begonias

You can never quite predict how severe our winter weather will be, but you don't need a crystal ball to know that some plants will need protection or lifting and storing to survive a winter.

Read full article