Petunias: planting, care & the best varieties
There are both hanging and standing varieties of petunias. We show where and how best to plant petunias and what to pay attention to the care of flowers.
Whether hanging petunias in hanging baskets or standing in balcony boxes, petunias (Petunia) are a must for any balcony with their large, cup-shaped flowers that shine in a wide variety of colours. There are a total of 16 species, most of which originate from South America. Its name also comes from there: the botanical name Petunia derives from petun, the Brazilian natives’ word for tobacco. In fact, petunias are very closely related to tobacco and, like tobacco, belong to the nightshade family (Solanaceae). Garden petunia (Petunia × hybrida) is a hybrid produced from several species of the genus. The flowers range in hue from white to red, purple and yellow. So there is something for every taste. To get the most out of your petunias, there are just a few things to keep in mind when caring for these frugal flowering wonders. Here you can learn exactly what to consider when growing and caring for petunias.
Contents
Planting petunias
As a true South American, the petunia prefers a location in full sun. However, heat-resistant plants also thrive in partial shade. However, not quite as many flowers will be formed there as in full sun. Also ideal is a place protected from the wind and rain. For example, your plants will thrive on a beautiful sunny balcony as if they had never left their home.
The right soil
A well-drained soil should be used to avoid waterlogging. Petunias prefer soil that is rich in nutrients. Rich compost or potting soil can be used for planting. Unfortunately, petunias often suffer from iron deficiency. This can be recognised by discoloured leaves with green leaf veins. This characteristic discolouration first sets in on the younger leaves. Special petunia soil is available in specialist shops to counteract iron deficiency. This soil has a low pH, which counteracts the increase in pH caused by watering with water that is too hard. Hard water has many minerals that cause the pH in the soil to rise. However, iron is most available to plants in the soil at a pH of 4.5. The use of a slow-release fertiliser when planting is also recommended.
Planting petunias in a pot
Petunias are classically planted in window boxes. Here or in hanging baskets, hanging petunia varieties with their long, flowering shoots come into their own. Standing petunias are particularly suitable for planting in the garden. However, some hanging varieties can also be planted in the bed as ground cover. When planting in a planter, it should have about 3 cm more circumference than the root ball. Good water drainage should be provided by a drainage layer at the bottom.
Hanging petunias need a little more space than the upright varieties because of their long shoots. The plants are then best placed in the soil only up to the upper edge of the roots. This should be well watered after planting, so that the plants immediately feel comfortable and have enough water. When filling the soil, cavities are removed by gently pressing. It is important to do this really gently, otherwise the soil can easily become too compacted, making root growth and water drainage difficult. If several petunias are planted next to each other, a minimum distance of about 30 cm should be maintained between the plants.
The right time for planting petunias
Petunias are not sensitive to light frost, but as sunny South Americans, they easily get cold feet in the spring in our climes. This means you should put the plants outside only around mid-May – then your little plants will be safe from frost.
Summary of how to grow petunias:
- Location: Sun to semi-shade
- Protected from rain and wind
- Permeable, rich soil
- Petunia soil to avoid iron deficiency
- Planter: balcony box, hanging basket, tub or planting in the bed
- Planter with good water drainage; drainage at the bottom
- Distance between petunia plants min. 30 cm
- Planting from mid-May (no longer a danger of frost)
Plant care
Petunias are very frugal plants and show that true beauty does not require much care. With the right knowledge, you can ensure that these natural beauties are shown to optimum effect.
Watering petunias
Petunias require regular watering, because they need a lot of water. But waterlogging should be avoided at all costs. To prevent the leaves and flowers of the plants from sticking together, you should water from below. Soft tap water or rainwater is best suited for this purpose.
Fertilising petunias
In general, it is a good idea to work a primarily organic slow-release fertiliser such as our Plantura Flower Food into the soil directly at planting. In addition, some compost can also be added to the potting soil to provide sufficient phosphorus for abundant flowering. Alternatively, fertilise monthly with liquid fertiliser such as our Plantura Liquid Flower Food until plants are well advanced in bloom. After that, the fertilisation frequency is increased to every one or two weeks. A phosphate fertiliser can be used to strengthen the plants and aid flower formation. If watered with hard water, it is best to use an additional iron fertiliser.
- Perfect for flowering plants in the garden & on the balcony
- For healthier plants with beautiful & long-lasting blossoms
- Long-lasting fertiliser that is free from animal products - child & pet friendly
Pruning petunias
In and of themselves, petunias do not need to be pruned. However, withered flowerheads should be removed regularly. This prolongs the flowering phase of the plants. If you want to overwinter your petunias, radical pruning of the shoots to about 15 cm is carried out before and after overwintering. In our article “Petunias: Care and successful overwintering” you will learn all the details about pruning before and after overwintering, as well as further details and valuable tips on proper care.
Summary: How to properly care for petunias
- Water generously, but avoid waterlogging
- Water from below
- Use soft tap water or rainwater
- Use a slow-release fertiliser (at planting and after 2 months later). Alternatively: fertilise monthly with commercial liquid fertiliser until flowering is well advanced, then every 1 to 2 weeks
- Strengthen the plants with phosphate fertiliser
- Additional fertilisation with iron fertiliser
- Remove faded flowerheads in the summer
- Radical pruning before and after wintering
- Perfect for all flowers & balcony plants
- Liquid fertiliser for a lush blossom throughout the season
- Quick & easy application - child & pet friendly
Propagating petunias
You can buy petunias every year or save a few euros by taking the propagation of these colourful balcony-dwellers into your own hands.
Propagate petunias by cuttings
The cuttings are best cut in the summer. For this purpose, 10 cm long side shoots are cut off. The leaves are removed (except for the top pair of leaves). Either place the cuttings in lime-free water until they take root, or put them directly into a pot with soaked growing soil. Once the cuttings sprout anew, enough roots will have formed to repot the plantlets into a larger planter. Starting in February, petunias are acclimatised by placing them outside on frost-free days. Planting takes place from mid-May, when there is no longer a danger of frost.
Summary of how to propagate petunias:
- The cuttings are best cut in the summer
- Use shoots 10 cm long
- Remove all leaves except the top pair
- Place in a glass with lime-free water until roots have formed and then put in pots with soaked growing soil OR plant directly in the pots
- Propagation was successful when the cuttings sprout at the top
- Repot into larger planters & continue to cultivate as adult petunias
- Acclimatisation of cuttings before planting in mid-May
Sowing and propagating petunia seeds
The seeds of petunias can be harvested quite easily yourself. You can find out exactly how this works in our special article on propagating petunias. If this is too much effort for you or if you simply do not own any petunias yet, you can simply buy the seeds in a specialist shop.
The seeds are sown from February onwards. To do this, fill a sowing tray with germ-free sowing soil. The tiny black seeds are mixed with dry quartz sand and spread evenly on the soil with sufficient spacing. Since petunias are light germinators, a maximum of a fine layer of soil is spread over the seeds. The temperature should not fall below 20°C during germination. At lower temperatures, the whole process takes considerably longer. The soil is kept moist with a water sprayer. Germination takes place under a foil hood in a bright location without direct sunlight. From germination, the foil hood must be lifted briefly every day for ventilation. From the formation of two pairs of leaves, the plantlets are pricked or transplanted individually into small pots. The plantlets need to be acclimatised before moving outside. To do this, they are placed outside during the day and brought back inside in the evening. From mid-May, the plants can finally go outside.
Summary of sowing by seed:
- Sow from February in sowing tray with germ-free sowing soil
- Spread seeds on the soil (be careful of light germination!)
- Ideal germination temperature: min. 20 °C
- Keep soil evenly slightly moist with water sprayer
- Cover sowing tray with foil hood (from germination ventilate 1x daily)
- Bright location without direct sunlight
- From the formation of the 2nd pair of leaves: prick out or transplant individually into small pots
- Acclimatisation of the plantlets before planting outside
- Planting outdoors from mid-May (no more danger of frost)
Petunia varieties: hanging and standing petunia
The different varieties are traditionally divided into four groups of varieties, of which ‘Grandiflora’ and ‘Multiflora’ are the most important. Petunia varieties are very different from each other not only in terms of growth habit. They also vary in flower shape, colour and size. There are varieties with small or large, single or double flowers, star-shaped, fringed or more rounded petals. We have put together a selection of particularly beautiful petunia varieties for you.
Hanging petunia varieties
Hanging specimens are the balcony classic, as their shoots grow beautifully over the boxes and tubs. They have beautiful, large and usually showy flowers. Some varieties are also available as mini-petunias. They have much smaller leaves and flowers, but overall the same size. Watch out: Nana hybrids of hanging petunias are very susceptible to rain and wind.
- Night Sky: As the name suggests, the large flowers of this variety are reminiscent of a night sky filled with stars. The violet-blue base colour of the flower is peppered with white spots that resemble twinkling stars. No two flowers are alike, which makes this variety particularly fascinating for the observer. It was even awarded the FLEUROSTAR in 2015/2016. Hanging variety with shoots up to 100 cm long.
- Lightning Sky: The flowers of this cultivar have a white eye and a dark crimson and star-like edge with prominent white speckles. Hanging variety with 40 – 60 cm long shoots.
- Viva®: VIVA® petunias, with their double flowers, are among the most special varieties. Here double also means double flower power. Despite their large flowers, they are very resistant to weathering, and the variety is available in different colour varieties. Hanging variety with 120 cm long shoots.
- Chocolina: This variety, with its rather small, chocolate-coloured flowers, looks good enough to eat (but please, do not snack on them). It has a bushy, only slightly drooping habit with shoots about 40 cm long.
- Daybreak: Surrounded by a pink morning glory, the yellow eye of miniature petunia ‘Daybreak’ comes into its own. It has a drooping habit with shoots up to 60 cm long.
- Pirouette Red: The Pirouette Red is a variety with double flowers. The red eye is framed by a beautiful white. It grows hanging with shoots 30-40 cm long.
- Big Time Blue: Although this variety has a comparatively plain appearance with its dark blue flowers, it is particularly robust and undemanding in care. The hanging shoots grow to about 100 cm long.
- Double Pink, Double White: These are mini petunias with double flowers, which are already all the rage in the USA. Not without reason, considering that the flowering shoots of the plants can grow more than a meter long.
- Burgundy Star Wave: The flowers of this hanging petunia are intense burgundy with star-shaped white stripes extending from the centre. The hanging petunia reaches a shoot length of 80 cm.
- Chameleon Double Pink Yellow: This hanging mini petunia changes flower colour depending on the season. The spectrum ranges from yellow to red to orange. The plant forms hanging shoots of 40-60 cm.
Standing petunia varieties
Standing petunias are rather small plants, but they bloom beautifully and in many colours. They grow upright as a small bush and are suitable as bedding plants as well as for container planting.
- Amore® Queen of Hearts: Here the name says it all: with red hearts on a yellow background, each individual flower proclaims a message of love. It reaches a height of 40 cm.
- Crazytunia® Stonewashed: With this variety, no two flowers look alike. The colour palette ranges from strong to delicate purple to creamy yellow. It is hardy, weather resistant, vigorous and continuously flowering. The height of growth reaches 30-50 cm.
- Duet Double Petunia: The double flowers feature an impressive play of colours of their salmon, pink and white tips. Attention should be paid to a sheltered location. The variety has a height of growth of 40 cm.
- Mirage Red Morn: Makes any bed shine with its red edged flowers with white eye. Here a growth height of 40 cm is reached.
Overwintering petunias
Most petunias that are commercially available here are annuals. We enjoy their blossoms until the first frost, but then they start their final journey to the compost. But does it really have to be that way? The answer is: No, it does not have to. The plants can also be overwintered. Petunias need to move to sheltered winter quarters before the first frost. This is the case in September or October. The plants are cut back to a shoot length of 20 cm and overwintered in a bright place at 5 – 10 °C.
During overwintering, plants are watered only so that the soil does not dry out completely. In addition, fertiliser is not used. Beginning in February, hibernators are then slowly awakened by placing them outside during the day on frost-free days. From mid-May, when there is no longer a danger of frost, they can finally move outside again. More details and tricks for successfully overwintering petunias, can be found here.
