Friday 30 September 2011

October jobs in the Dahlia garden

October is a time for house-keeping your dahlia garden and preparing to lift the tubers.  I am hoping that we can continue cutting for 2/3 weeks into October as the plants are still strong and robust, probably because they had a delayed start.  There is now no need to water the plants.  Look out for the onset of Dahlia Smut; this occurs in cold, damp conditions and appears as paler spots on lower leaves that may spread to all leaves. To control culturally, if at all possible remove all affected leaves.  To control by intervention use a fungicidal spray such as Bordeaux Mixture.  The fungus may lay dormant in the soil so clear away and burn all affected leaves.  However, there should be no long term damage to the tuber if dealt with promptly.

If you have been cutting frequently, as well as dead heading, you will see that stems have the remains of the main shoot and the two primary side shoots, see image 1.  To promote continued strong growth prolonging the flowering season as long as the weather permits these should b, in effect, pruned back.  That is, cut the stem back to the leaf node below that has side shoots showing, See image 2.

Image1: Before pruning back. 

Image 2: after pruning back, the side shoots can be seen by the leaf node.

All plants that are to be discarded should be either removed now or clearly marked to prevent any mix up should they be frosted.  If your bed is to be used for spring bedding it would be time to cut back and lift the tubers in the middle of the month.  However, ideally one can wait until the frost blackens the foliage forcing the sap back into the tuber.  Cut the stems back to 12 / 13 cm before lifting.  Trying to lift before cutting the foliage back may result in the stems splitting and damaging the crown of the tuber.  Label clearly, bring inside and place upside down to drain all the sap out.  

Later in October bring into the greenhouse all pot tubers lying them down on their side to dry off.

Remember to pay your National Dahlia  Society subscription due in November!

Sunday 4 September 2011

Dahlia jobs in September

September is a month when the jobs are a continuation of August; keep feeding and well watered until the end of the month as necessary.
Keep dis-budding as required and maintain the dead-heading; this will stimulate and speed up the growth of more flowering side shoots.
Make sure all plants are labelled while in flower!  It is so easy to forget and identification when frosted is difficult.  Keep the routing hygiene going and stay on the look-out for the dreaded insects; wasps, earwigs and caterpillars.
If you have the opportunity do visit dahlia nurseries to see exactly how the different cultivars grow in terms of height and habit.

We've had a terrific August as we are now supplying New Covent Garden Flower Market with blooms twice a week and am getting great feedback from both the market and the market customers.  When we scaled the operation up there was always that doubt that we would not be able to get all the blooms to the consumer, through New Covent Garden we are.  The real barrier for British cut flower growers is getting the florist trade and consumer to insist, where possible, on British grown cut flowers.

£2.2 billion is spent on flowers in this country, that is more that the music industry, over 85% are imported.  Flowers are flown in from Africa, South America and Asia; just think what that does to the UK carbon footprint!  Not only that but it has over the past 20 years as imports have risen, put many British growers out of business.  However, do not expect British cut flowers to be cheaper because they are British!  But you do get a quality product that is supporting the local horticultural industry and it will, over time, reduce the carbon footprint.