Reducing Chemical Dependency in Daphne Production | Osberton Nurseries

Carl's BASIS project explored the potential of biostimulant Vitalnova Prime at Osberton Nurseries to reduce reliance on chemicals in Daphne production

2 mins
Carl Mason
ICL Ornamental Horticulture, Technical Area Sales Manager

Technical Area Sales Manager Carl Mason joined the BASIS professional registration in 2022.  A rigorous and highly effective industry self-regulation scheme, BASIS demonstrates professional competency and up-to-date expertise in the rapidly changing and technically demanding area of pesticides. Only advisers with the BASIS qualification can legally advise growers on the full range of crop protection products. 


Specialist ericaceous plant producer Osberton Nurseries operates from a 20ha site on the picturesque Osberton Grange Estate. Primarily producing a colourful and exciting range of quality Rhododendrons, Camellias and Azaleas, the product range also includes Daphne.


“Daphne can be a sensitive crop as rooting is often poor,” explains Carl. “Plants often develop root problems such as Phytophthora, Pythium and Rhizoctonia, while the foliage is prone to botrytis and fungal leaf spots. This cosmetic damage can make plants unsaleable and overall losses during propagation are often high.  


“In a bid to reduce reliance on robust chemical treatments, we set up a trial using Vitalnova Prime to help stimulate root growth.  Better rooting leads to healthier plants and increased growth. Helping to reduce losses, it results in more saleable plant – ultimately more ‘Grade A’ plants.”  


Vitalnova Prime  

Vitalnova Prime works through the plant leaves and roots.  It initiates induced systemic resistance (ISR) action, delivering greater protection throughout the plant.  It is best applied through a heavy spray to point of run off from the leaves – a ‘sprench’– midway between a drench or spray. By applying regularly, every 10 – 14 days, the plant goes into a heightened defence mode producing natural elicitors; these keep it on high defence against abiotic and biotic stresses. 




Seven bays of Daphne plants were include in the trial.  The plug plants were potted into 1 litre liners in February 2020 and re-potted into 3-litre pots in October. The tried and tested 30% peat-reduced growing media had an open structure for rooting and drainage and contained 2kg of 12 – 14 months Osmocote controlled release fertiliser. The pots had a bark topping for weed control.  

Starting in March, 3 bays of Daphnes were treated with Vitalnova Prime every 10-14 days till the sale of the crop. Meanwhile, the other 4 control bays were treated with Osberton’s standard PPP programme – consisting of Serenade ASO (EAMU), Signum (EAMU) and Switch.





Good results were achieved in all seven bays.  However, the Vitalnova Prime programme produced better root development and slightly bigger plants with more flowers, compared to the controls (standard PPP programme).  


“While biostimulants are not silver bullets, or replacements for chemicals, they can play an important role to help growers reduce chemical usage,” says Carl. “Should a major disease incidence occur, we can currently switch to chemicals to clear up the problem and then start again.   

Costings showed that the total cost of the chemical treatments in the trial was £173.36 (four bays – £43.34 /bay) while for the biostimulants it was £37.20 (3 bays – £12.40/bay) – a saving of over £30 /bay.  

“There are certainly cost savings to be made compared to chemical treatments and these products do not need to be applied by a qualified spray operator,” says Carl.   

Commenting on the results of the biostimulant trial Graham Newbury says: “the Vitalnova Prime treated Daphne plants grew very well – the quality of the root structures was noticeably better, as was overall plant quality. Overall fungicide usage was reduced where biostimulants were applied.   


“Moving forward, we intend to use Vitalnova Prime in our Daphne production and we’re also planning further trials with certain Rhododendron varieties, such as Albert Schwitzer, that can struggle early on in the field.”