Garden Pests & Disease

There are many garden pests and diseases that provide year round challenges to the growth and health of our garden plants.

A great many of these are well documented, and now easily recognisable - and manageable by garden enthusiasts. However there are a few that seem to be less well publicised, or surrounded in 'mystery' - leading to a great many questions from confused and disappointed people.

We have focussed on a couple of the less well understood problems below.

Cordyline Sudden Decline Syndrome

Older, taller Cordylines are more susceptible to this syndrome than younger ones.

A tell-tale sign of problems may be yellow leaves strewn across your lawn! The syndrome can be identified by yellow coloured leaves – the oldest of which then wither and fall off.

New growth is likely to be stunted, and then eventually all of the leaves will fall off, revealing dead looking branches, often with dried flower panicles still attached.

As the bark of the trunk dries and becomes easily detached, so too can the top of the trunk, die and fall out.

There is no logical discrimination between victims – in a whole row of specimens; it can be just a single tree that's affected by the syndrome. There’s also no evidence to show that the condition will spread to nearby specimens if one is affected.

It may go undetected as Sudden Decline Syndrome due to the fact that people often mistake the syndrome symptoms as the result of cold temperatures or a bad winter.

There is evidence to suggest that chopping the tree down to the ground can rid it of the syndrome, although success with this method of management has been mixed.

Quite often, the only real solution is to plant a fresh new, young Cordyline – which won’t be affected by the syndrome like its more mature relatives.

Escallonia Leaf Spot

This fungal disease may not be detected until late summer / autumn in August or September. Around this time, purple-black spots will appear on the leaves, often several spots on the same leaf.

The spots may develop a white centre, in which black dots, indicating fungal fruiting bodies, may be visible.

The leaves affected will then start turning yellow before dropping from the plant, leaving it apparently deciduous over the winter.

This fungal disease has affected a lot of Escallonia hedges across the country, and many of the old Escallonia hedges in Cornwall, which have been around for 30+ years.

New leaves may grow again the following spring but these are likely to become symptomatic again – affirming a recurring problem for the plants’ remaining lifespan. As time goes on the plant’s vigour will be affected and the problem is likely to become more severe, leaving dead or dying patches in the hedge.

Whilst the lifespan of the hedge may be extended for a few years by cutting it back hard, to stimulate new growth; and by feeding it well to improve strength, the reality is, it’s deteriorating and will eventually die off. In addition, no current chemical control or management is known to exist that can cure or manage the disease.

A disease specific to Escallonia, the best solution is to replace it with a different hedge altogether. At Trevena Cross we have stopped growing Escallonia in favour of superior coastal hedges, like Elaeagnus and Griselinia, which don’t suffer with such problems.

Category: Spot

Similar articles: