Growing Tuberous Begonias in the UK

Growing Tuberous Begonias in the UK

The second raving post about Begonias.
Beggars Begonias

Begonias are native to all parts of the world except Australia and Europe. The South American species have been bred in England since the 1860’s and we can now enjoy many colourful varieties. Grow as houseplants or for borders.

Growing Begonias from Tubers

  • Growing begonias couldn’t be easier. Buy good stock, firm to the touch.
  • Plant the rounded tuber with the indented surface upwards and the roots downwards.
  • Start tubers off between February – April in frost free conditions. You can put several in a tray until new roots are formed.
  • Cover with damp peaty compost until only the top of the tuber is visible level with the compost.
  • When the tops are 2-4″ tall roots should be good enough to pot-on. That is plant in the begonia in it’s final home be it indoor pot, outdoor container or border.
  • Water in then leave until compost is on the dry-side to encourage new roots to search out more moisture.
  • Thereafter water and feed your pot begonias as they are thirsty plants.

Begonia Buds

  • Begonias are very free flowering and may try to flower before enough energy has been built up.
  • When the first small bud cluster is as large as a 10 pence piece lift it upwards and backwards and snap it off.
  • Future flowers will reward you for this effort.
  • Begonias bud in 3’s and the central bud is the dominant male which will be double. The single female side buds can be taken off to channel the energy into the main flowers.
  • Bedding begonias do not need to have the side buds taken off but do nip out the first buds to get a strong plant.

Side bud ‘single’ takes energy from central flower.
Photo by Art Poskanzer cc


Why grow Tuberous Begonias

  • Begonia look like exotic flowers when grown from good tubers. The colours are vibrant and varied although the above white is one of my favourites.
  • They are very popular in the USA but less so in the UK.
  • Begonias make good cut flowers – give them a long drink immediately after cutting then they will stay firm for several hours without flagging and last for many days in an arrangement.
  • Float them in large bowls or on top of brandy glasses as a different way of displaying them. Even the small end of season flowers or the smaller male and female flowers either side of the main male flower will hold their rigidity.
  • Picotee Begonias are not a different variety but differ only in the petal colouring which is edged with Red or Pink. this has produced some good hybrids such as Corona, and Harlequin. Wedding Day is white with slightly pink outer petal blush that can give a Picotee effect.

St Just Truro Begonia

Special Begonia Tips

  • Tip – Begonias are asymmetrical so they have a definite front and back. So I recommend staking them from the back, with a thicker than normal cane, sloping about 10° from the vertical so that when it is tied with a flat tie it draws the stem into the vertical. Take care not to put the stake so close that it goes through the tuber.
  • Tip – First flowers in a season are often produced before the Begonia has enough stamina to sustain them, so if you want great blossom be ruthless and disbud the first flowers to divert energy into later flowers.
  • Tip – Vine weevil grubs are a great pest eating the tubers from Autumn. The egg laying brownish beetles like ferns so watch out if you grow them in close proximity otherwise a chemical treatment will be needed. Water can be a barrier method and I guess the little grubs can’t swim.
  • Slugs and snails can also be a problem.
  • St Just Truro Begonia snail

Begonias for Showing

      The Flower

      The flower is judged in three respects:

      1. The depth from the front to the rear of the flower about 1 inch less than the diameter of the flower.
      2. Secondly the individual petals must be broad 2-3 inches and of good substance
      3. Thirdly the flower should have a rose shaped centre. Muddled or multiple centres are unacceptable
      4. Gardeners may want to add the lasting or keeping quality.

      The Tuber and Plant

      1. Tuber size isn’t everything but a good sized tuber will store better throughwinter
      2. Vigour and resistance to disease are key features of a plant
      3. The ability to throw cuttings for propagation either basal or stem cuttings

      Gardeners Tips for Begonia

      • As cut flowers they need a good drink immediately after picking and they will then hold the rigidity
      • Seedlings are small and frail but can be handle by with narrow slivers of wood or a notched end cane
      • Begonias don’t like limey or sandy soil so add manure or peat.
      • Disbud the first few flowers to strengthen the plant then it will flower strongly from the beginning of August
      • Named varieties should have been propagated from cuttings and are more expensive than unnamed varieties
      • Start tubers by covering them in moist compost with modest heat
      • Stake the shoots at the back, begonias are asymmetric and have a distinct front

      Types of Tuberous Begonia

      • The old fashioned Camelia and Rose form of double begonias
      • Picotee have an attractive red edging to the petals
      • Frilled doubles or Frimbriata can be deeply serrated to the point where the petals loose individuality
      • Multiflora begonias bear a profusion of smaller flowers and can continue blooming for a long perios as a pot plant indoors.
      • Facination, Crested and Crispa marginata types are dropping out of cultivation

    St Just Truro Begonia
    Useful Links

    This backend the Begonias have given a special show in fact it beggars belief how well they have done. I am not an out and out favourite of the lard show begonias that tend to be one sided and fragile for my wet and windy window sills (outdoor). However for massed planting the pink too rich salmon-orange, fully-double flowers of Begonia Peardrop have a yellow hue which comes and goes throughout the year, whilst the rich dark foliage provides a stunning contrast to these magnificent flowers.
    Next year I intend trying the new scented variety in a similar colour range called Begonia Begonia aromantics®


    This bloom has picotee petals that is a light ground with an edging of deeper pink. Tubers vary when flowering even on the same plant.

    The whole bloom is worth attention with the fascinating pattern of the opening petals. For this reason Begonias make great plants for growing in raised beds or pots.

    Begonias shed the old flowers and it is not usually worth deadheading except to keep the plant tidy.

    Begonias are unisexual having both male and female flowers on the same plant. The female is usually single.

    Other Resources

    Royal Horticultural Society RHS ‘Gardening for All’
    National Council for Conservation of Plants and Gardens ‘Conservation through Cultivation.’
    Garden Organic National Charity for Organic Gardening.
    BBC Gardening

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