As one of our main priorities at this time of year is bringing a huge selection of summer bedding and patio plants to our customers, we thought we’d share with you one of the most publicised current issues relating to the popular, much loved bedding plant, ‘Busy Lizzy’ – which has impacted our careful and ‘safe’ selection of particular varieties of this summer favourite in 2012.

Impatiens (commonly, Busy Lizzies) have been the subject of a fungal disease called Downy Mildew, which manifests itself through yellowing leaves, leaf loss, and plant death. Whilst it has been in circulation in the UK since 2003, having most likely arrived on imported commercial propagation material (seed or cuttings), it only really became unmanageable last year.

Impatiens

Statutory action was initially undertaken by the Food and Environment Research Agency (fera) against confirmed outbreaks of the disease, on its discovery, but this action soon ceased.

After the wet summer of 2008, damage was much reduced by improved control practices at commercial nurseries but then in 2011 any established control failed, probably due to resistance to the commercial fungicides used. Infected plants were inadvertently sold widely, which led to the most widespread outbreak of the disease to date, with many gardens, nurseries and local authority displays affected.

Outbreaks of Downy Mildew have been confined to Impatiens walleriana, the common bedding Busy Lizzy. No cases have been found on New Guinea impatiens, or other varieites including Impatiens × hawkeri, and the few species found growing in the wild in the UK.

Attacks are most likely in spring or summer in greenhouses, and often during wet weather or damp conditions – which can often mislead people to believe that it is the moisture at the core of the problem, rather than the disease spreading spores.

We would advise against purchasing any Impatiens that may be affected by or vulnerable to Downy Mildew, instead sticking with those found to be resilient / immune, or alternatively replacing them with a selection of other bedding types, such as Begonias.

Prevelence of the disease has certainly led to us to reconsider our bedding choices, with the decision to focus more heavily on other, equally showy and colourful options this year, and keep our impatiens offering down to only unaffected New Guinea ones – a safe way to ensure quality bedding plants and help avoid further spread of this persistent killer.