August-Sunloving Petunias

If you are like many, living a hectic lifestyle with precious little time to potter around the garden, then Petunias are for you. They are one of those rare gems that reward very little care with masses of blooms.

There’s a wide range of Petunias will brighten up any sunny spot with the minimum of attention, giving you months of stunning colour. The modern hybrids can take a bit of cold, so can be grown on the Highveld during winter as long as they are planted in a warm, sheltered part of the garden. Petunias that have become established during winter give a breathtaking spring display.

Petunias are easy to grow, bloom reliably for months on end and are available in a wide range of colours, flower forms, and growth habits. That’s not bad for a couple of trays of seedlings from your local garden centre.

Planting Tips

When planting Petunias, whether in containers, window boxes or beds, placing them along a north-facing wall is preferable, as it will trap a lot of heat and light. These are a prime growing position for petunias and will encourage them to flower throughout winter and spring – for up to five months! Those that are planted in cooler areas – even if they get full sun – will grow and establish in winter and burst into colour in spring and continue well into summer.

Whilst your soil needn't be particularly rich to grow good petunias, it must drain well. It's always useful to improve the soil by conditioning it with organic matter, such as, compost and a little well-rotted manure. 

Tips to success

  • Never plant new petunias in a bed, container or window box where you have just removed a successful Petunia display.  Rather give that soil time to renew itself from any potential disease build up as roots left behind by old petunias are inclined to build up pathogens that will attack new plants.
  • Successful pot displays always require that the soil is prepared well and good drainage is a prerequisite.  Ensure container holes are not blocked before planting. Soils that do not dry out quickly should have plenty of compost and river sand added to assist drainage. Waterlogging is a death knoll to Petunias.
  • Petunias will reward when well fed, so a good general purpose fertilizer should be incorporated into the soil before planting. For those who want a spectacular show of blooms, a folia feeding program will give best value for money.
  • When buying seedlings avoid yellow leafed petunias or any that show signs of damping off in the trays. Select compact, stocky plants. Tall, spindly plants take considerably longer to recover from transplanting.
  • Do not pull seedlings out of the tray by their stem or leaves, as this will damage them.  Rather push them out from below.
  • Don’t bury the stems of the seedlings when planting, rather plant to the depth that they are in the seedling tray.
  • After planting, water regularly until seedlings are established.  Once established the secret behind successful Petunias is to allow the soil to dry out in between waterings. This is particularly important as the drying out cycle encourages them to flower more profusely and keeps pathogens at bay.
  • Once well established, the best fertilizer to encourage flowering is 3.1.5., or use a foliar feed high in potash.
  • Deadhead regularly by removing any old flowers including the calyx. This will encourage the plant to produce more flowers and also give you a longer blooming period.
  • Keep an eye out for snails when the plants are still small.
  • If the habit of the plant is scraggly, nip out growing tips to encourage branching. 

Top Tip

Petunias can be grown all year round in most parts of the country – the trick is to plant the right variety at the right time. “Grandiflora” Petunias have large, bold blooms and are ideal for planting in autumn and winter in summer rainfall areas. “Multiflora” Petunias have masses of smaller flowers and are better suited for planting in spring and summer in the summer rainfall regions as the smaller flowering varieties are more tolerant of rainfall.

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