Science into practice: Keeping Cordyline/Phormium cultivars healthy

Fashion for tropical-looking plants and our milder winters have combined to encourage a resurgence of interest in a range of Cordyline and Phormium cultivars.

Growers reported problems affecting production, so the HDC commissioned a study. HNS 171 is designed to provide information on the scale of problems and consider what further investigations and production strategies are needed.

The study involved a review of information from literature, growers and consultants relating to the pests, diseases and disorders affecting production. A survey of 44 growers provided an overview of the difficulties faced. Case studies then provided in-depth information on current practice in producing these crops and combating the problems experienced.

The most problematic pests, diseases and disorders for Cordyline were two-spotted mite, yellow-leaf spot syndrome, tip-burn and "wobble" or "rock". For Phormium they were Phormium mealybug and two-spotted mite. A number of the conditions reported require further investigation; however, there were some suggestions that may help improve quality.

Avoid over-watering in late winter/early spring to control yellow-leaf spot syndrome and increase ventilation and spacing. For leaf-spot control, avoid wetting leaves and apply irrigation early to enable leaves to dry off before temperatures drop. Key to controlling Phormium mealybug is to quarantine stock on arrival and check each plant for infestation. Predators to control two-spotted mites can be difficult to establish; there are acaricides available, but the waxy leaves of Phormium make an adjuvant necessary. Control tip-burn by water management and calcium supplements.


Have you registered with us yet?

Register now to enjoy more articles and free email bulletins

Sign up now
Already registered?
Sign in

Read These Next

Tractors: market roundup

Tractors: market roundup

Manufacturers are working to provide solutions to many challenges. Sally Drury looks at their newest models.



Brightening up gardens in autumn, these daisies are seen as a gem in the gardener's arsenal, writes Miranda Kimberley.

Are tree suppliers seeing the benefit of the health message of trees?

Are tree suppliers seeing the benefit of the health message of trees?

The message that health, the environment and business all benefit from trees is finally getting through, but are nurseries seeing an upturn? Sally Drury reports.

Opinion... Why no-deal Brexit should worry you

Opinion... Why no-deal Brexit should worry you

Whether you voted leave or remain all those years ago, a "no-deal" Brexit should worry you.

I will not be importing oaks this season. Will you?

I will not be importing oaks this season. Will you?

I find myself in a difficult situation. A few weeks ago I was fortunate to be present to hear details of imminent changes to regulations concerning Oak Processionary Moth (OPM) and oak trees. I heard details, asked questions and probed the implications of these changes. That may not sound like a difficult position to be in, yet I am uneasy.

Opinion... Better targets to tackle pollution

Opinion... Better targets to tackle pollution

Lobby groups jumping onto fashionable campaigns, often to promote their own interests, can do much more harm than good. Take, for example, the move against black polythene plant pots and containers.

Follow us on:
  • Facebook
  • LinkedIn
  • Twitter
  • Google +
Horticulture Jobs
More Horticulture Jobs

Horticulture Week Top 60 Ornamentals nurseries

See our exclusive RANKING of ornamentals nurseries by annual turnover plus the FULL REPORT AND ANALYSIS

Tim Edwards

Boningales Nursery chairman Tim Edwards on the business of ornamentals production

Read Tim Edwards

Pest & Disease Tracker bulletin 

The latest pest and disease alerts, how to treat them, plus EAMU updates, sent direct to your inbox.

Sign up here

Are you a landscape supplier?

Horticulture Week Landscape Project Leads

If so, you should be receiving our new service for Horticulture Week subscribers delivering landscape project leads from live, approved, planning applications across the UK.

Peter Seabrook

Inspiration and insight from travels around the horticultural world

Read more Peter Seabrook articles