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How to grow petunias and best varieties
Petunias are great for summer hanging baskets and patio pots. Learn how to grow them and try our Best Buy varieties
Petunias have long been a summer favourite. Now calibrachoas, their smaller-flowered cousins, have been bred with them to create petchoas, which are the size of petunias but with the striking colours of calibrachoas.
The Which? Gardening magazine trial pitted them against each other to discover which ones flower best in a British summer. We also share our advice about how to grow petunias in hanging baskets and patio pots.
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Key facts
Plant type Tender perennial, usually grown as an annual
Position Full or part sun
Soil Well-drained and fertile
How to grow petunias: month by month
| January | February | March | April | May | June |
| Pot up indoors | Pot up indoors | Move outdoors | |||
| July | August | September | October | November | December |
| Flowering | Flowering | Flowering | Pull up |
Best petunia varieties
Full testing results for petunias
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.
| Variety name | Overall rating | Height x spread (cm) | Flowering duration | Flower impact | Flower coverage | Shape for pots & baskets | Resistance to wind and rain | Pests & disease |
|---|---|---|---|---|---|---|---|---|
| 'Amore Queen of Hearts' | ||||||||
| 'Chameletunia Mango' | ||||||||
| 'Circus Sky' | ||||||||
| 'Darcey Rosa' | ||||||||
| 'Night Sky' | ||||||||
| 'Purple Tie Dye' | ||||||||
| 'Royal Sky' |
The more stars the better. OVERALL RATING Ignores price and is based on: flower duration 25%; flower impact 25%; coverage 20%; shape 15%; weather resistance 10%; pest and disease resistance 5%.
Best petchoa varieties
Full testing results for petchoas
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.
| Variety name | Overall rating | Height x spread (cm) | Flowering duration | Flower impact | Flower coverage | Shape for pots & baskets | Resistance to wind and rain | Pests & disease | |
| 'Beautical Caramel | |||||||||
| 'Beautical Cinnamon' | |||||||||
| 'Beautiful Sunray Pink' | |||||||||
| 'French Vanilla' |
The more stars the better. OVERALL RATING Ignores price and is based on: flower duration 25%; flower impact 25%; coverage 20%; shape 15%; weather resistance 10%; pest and disease resistance 5%.
Caring for petunias
Planting petunia in hanging baskets and patio pots
When your petunia plugs arrive you can plant them straight into pots or baskets, mixing in some controlled-release fertiliser with a Best Buy compost for containers.
Grow them in a light, frost-free place until you’re ready to move them outdoors when the danger of frost has passed. They do best in a bright, sunny spot but will tolerate light shade.
Discover our Best Buy pop up greenhouses
Watering
Petunias are drought-tolerant, but keep them well watered as they will dry out quickly in pots and baskets.
Try a Best Buy garden irrigation system
How to deadhead petunias
To keep your plants looking tidy and to help encourage them to produce more blooms, you can remove the faded flowers to the base of their stems. It's a sticky job, though, and many modern petunia varieties are 'self cleaning', so it's not vital that you deadhead them.
Learn about our Best Buy secateurs
Feeding
Controlled-release feed usually runs out towards the end of summer. When this happens, start giving a liquid feed once a week to keep the display going for longer.
Common questions
Are petunias perennials?
Petunias are tender perennials so are best thrown away at the end of the summer, as they won't survive the UK winter outdoors. Start new plants each spring. Some varieties are available as seed and can be sown indoors early in the year, while others are only available as plug plants from nurseries or garden centres.
Are petunias poisonous to cats or dogs?
Petunias are not toxic to cats or dogs, so you can grow them safely in your garden if you have pets.
Do bees like petunias?
We've never found that bees or other pollinators are particularly attracted to petunias in our trials. If you'd like to help these insects with your patio display, try our best patio plants for pollinators.
Common petunia problems
Greenfly
Squash any aphids before they can develop into larger infestations that might cause damage
Read more about how to get rid of greenfly
Slugs and snails
Slugs and snails can nibble holes in your plants. Scatter organic slug pellets sparingly around the plants or remove any slugs and snails you see.
Read more about how to get rid of slugs and snails
Powdery mildew
Petunias can be prone to the white coating of mildew, so make sure you keep them well watered to avoid stressing the plant.
Read more about how to treat powdery mildew on plants
How we test petunias
We chose a number of varieties of petunias and petchoas.
We planted three plugs of each variety in a 9-litre pot and also into a 30cm basket with our Best Buy compost for containers mixed with Best Buy controlled-release fertiliser.
We put them outside once all danger of frost had passed, and kept them watered with an auto-irrigation system.
We monitored them throughout the summer to see how good a display each variety gave and how long they flowered for. If any plants looked a bit pale or stopped flowering, we topped them up with a liquid feed in August.
We ended the trial in October.