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Home & garden.

1 October 2021

How to grow begonias

Begonias come in a huge array of shapes and colours. Discover our best begonia varieties and tips for how to grow them.
CT
Ceri Thomas
Begonia in a hanging basket

Begonias will bloom all summer long and into the autumn in patio pots and baskets, with little attention needed. They also do well in partial shade. As they're tender, they shouldn't go outside until the danger of frost has passed in the UK in mid- to late May.

Which? Gardening magazine grew a range of popular varieties to see which would give us the best display.

Key facts

PLANT TYPE Tender perennial

POSITION Partial shade

SOIL Best Buy compost for containers

How to grow begonias: month by month

January
February
March
April
May
June



PLANT
PLANT/MOVE OUTSIDE
FLOWERING
July
August
September
October
November
December
FLOWERING
FLOWERING
FLOWERING
FLOWERING


Best Begonia varieties

Which? members can log in now to see the full results and which are our Best Buy varieties. If you’re not a member, join Which? to get instant access.

Best Buy begonias
What it looks like
Variety name
Height x spread
50 x 60cm
There are various forms of this variety. We tried this form and were impressed with the display of double flowers, which varied from flame orange to cream and looked stunning against the dark green leaves. Starting with an upright habit, the plants swiftly grew to fill the basket and started trailing to form an almost perfect ball of colour. It surpasses the previous form, which we recommended in 2014. Peak flowering: June to September.
What it looks like
Variety name
Height x spread
45 x 75cm
This series of begonias has been around and looking good for some years. One was a Best Buy in 2014, and another was a Best Buy in 2012. In this trial, the masses of single, scarlet-red flowers of this variety made a dense ball of colour that couldn’t fail to be a Best Buy. This floriferous variety was already full of blooms at the beginning of June, and didn’t stop flowering for the entirety of the summer and into October. Peak flowering: June to October.
What it looks like
Variety name
Height x spread
30 x 50cm
The eye-catching, spiky, apricot-coloured double flowers of this variety a modern look that’s miles away from the big, blousy, traditional begonias. The serrated petals and central yellow eye also add interest. The plants filled the basket well in our trial, with plenty of trailing stems covered in blooms. The first flowers opened in June, and by July there was a spectacular display that lasted into October. Peak flowering: July to October.

How we test begonias

We planted 15 varieties of trailing begonias in hanging baskets at our trial site. The emphasis was on the many new begonias that have come on to the market in recent years, including new scented varieties. We added controlled-release fertiliser to our Best Buy compost for containers, before planting three plants in each 35cm-wide basket. The plants were hardened off before being put outside in late May. We assessed them throughout the summer for: Duration, impact and coverage of flowers; even growth and suitability for a basket; whether flowers had fragrance; How susceptible they were to common problems.

Caring for your plants

Planting

Most varieties are sold as plug plants. Order early to allow time to grow to flowering size. Plug plants arriving in spring need protection from frost.

Either plant in a basket straight away or, if you don’t have space, pot up the plants into 9cm pots and wait to plant your basket when it’s ready to go outside in mid to late May.

Three plants should fill a 35cm basket.

Before planting, add a Best Buy controlled-release fertiliser to a Best Buy compost for containers.

Gradually acclimatise your plants to outside temperatures before actually placing your basket outside, when all risk of frost has passed.  Ideally, place baskets somewhere that gets shade during the middle of the day

Watering and feeding

Water regularly, especially during hot weather, when pots and baskets will need watering more than once a day. The controlled-release feed added to the compost will keep plants looking good until late summer. But from mid-August, it's worth giving them a boost by feeding with tomato food.

Discover our Best Buy tomato feed

Deadheading

Most begonias are now ‘self cleaning’ and the dead flowers fall to the ground. If your begonia retains the old blooms, then pinch them off regularly to encourage more flowers.

Common growing problems

Powdery mildew

Powdery mildew appears as a white powdery coating on the surface of leaves, or as blotchy, pale yellow leaves. Remove affected leaves or use a fungicide.

Read more about powdery mildew.

Vine weevil

Notches eaten out of leaf edges are a sign of adult vine weevils. From August onwards, their grubs will eat roots, causing the plants to wilt even if watered well. Check the compost for small, white, C-shaped grubs. 

Read more about vine weevils.