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Graham Rice on Trials

Updates on trials and awards from the Royal Horticultural Society by Graham Rice

Carnation growing - up to date

Posted by Graham Rice on 06 May 2009 at 10:26 PM

Spray carnation 'Coquette'. Image ©Sue Drew/RHS Trials OfficeThe Wisley trials not only bring awards to the best plants, they also test new ways of growing them.

In recent years only dedicated specialists (and mass market cut flower growers) have grown perpetual flowering carnations but a new approach has recently been investigated at Wisley, a way in which more of us can grow these exquisitely coloured and superbly scented plants without keeping them permanently in the greenhouse as is so often considered necessary.

In fact, they can be grown in containers on the patio and two varieties of spray carnations, which are naturally branching and so ideal for this approach, stood out when grown in this way.

In February, five plants were potted into 10 litre pots of peat free compost. The plant in the centre was left to grow naturally while the four plants set around the edge were pinched back when they had seven or eight pairs of leaves. This pinching encouraged bushy growth on more compact plants and created a more elegant display which was taller in the centre. Discreet support was put in place towards the end of April, and half the stems on the outer plants were again pinched at the end of May.

Spray carnation 'Coquette'. Image ©Sue Drew/RHS Trials OfficeDuring all these preliminary stages the plants were kept in the greenhouse, with just enough heat to prevent frost; it would interesting to see how they perform with no heat at all. The judging panel noted that they are able to take low temperatures so it would be worth looking at.

The pots were moved outside in June, the plants flowered all summer and were left out all winter when two varieties suffered badly from the combination of unusually low temperatures and wet compost; it's the soggy compost they can't stand.

The plants were assessed by the judging panel every month and scores given for plant and flower quality; Sue Drew, from the Wisley Trials Office, counted and recorded every flower produced, Their diligence was impressive. While peak flowering was in July and August, October was also a strong month. 'Duke of Norfolk' was the most prolific in summer, the two pots (ten plants in all) producing 118 flowers in July alone, but this profusion did not make up for the less impressive quality of the plants (rated for impact, habit and health) and the quality of the individual flowers. It's not just about quantity.

Overall,the judging panel noted that two varieties in particular stood out. Both ‘Milky Way' and ‘Coquette', they said, showed consistently good growth and good flowers, with the pure white ‘Milky Way also noted for its lovely scent and ‘Coquette' for its unusual purplish maroon basal colouring, pale lilac pink towards the edge.

Spray carnation 'Milky Way'. Image ©Sue Drew/RHS Trials OfficeThis valuable experiment continues with six different varieties being grown for flowering this summer and next. But now that it's becoming clear that this is a useful way to grow these carnations, I'd like to see them grown in stylish containers (not just black or brown plastic pots), in a prominent position, and with companion planting in the same container. Sited where visitors will see them, outside the new glasshouse perhaps, the display would have quite an impact.

You can order plants of carnation ‘Coquette' from Allwood Brothers and Bofield Carnations will also be stocking it soon.

Plants of carnation ‘Milky Way' will soon be available from both Allwood Brothers and Bofield Carnations.



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