Login Register

GARDENING with ALI MARSHALL: Battling climate change in garden

By Herald Express  |  Posted: October 19, 2016


OLD ENEMY: The Colorado beetle, back in Europe after a break PA

Comments (0)

OCTOBER has become a quiet month in the garden these days. With so many plants still growing strongly it seems too early still to think about putting the garden to bed.

In Torre Abbey Gardens, for example, our dahlias are blooming better than ever (although I do have the advantage of a team of volunteers obsessed with deadheading) and the grass is still being cut on a lowish setting, against the advice of all my garden books.

My vegetable garden is producing quantities of exotic late season harvest so I currently have chillies coming out of my ears... and as for Jerusalem artichokes, I am awash with the darn things. Having brought back a few for sentimental reasons from my old allotment I now have a forest of them, largely due to the fact nobody here particularly likes eating them.

Although I am fond of the flowers I can't let this go on so, in the next few days, I will be digging the whole lot up. Next year I will grow sweet potatoes instead, which are a family favourite I currently have to buy from the supermarket... grrrr! No more sentimentality!

Even the recent easterly weather (my least favourite direction) has not affected my plants much. The shelter of the walls and house at Torre Abbey means we avoided any real damage from the salty easterly winds which have blown through, so I was surprised to notice greenery facing the sea at Saltern Cove (my dog's favourite place) had been blasted into a blackened, shrivelled tangle of death.

I don't remember seeing anything quite like it before which has got me to thinking yet again whether this is something climate change is responsible for.

Like most gardeners, being outside among plants for so much of the time means I notice changes caused by weather on a daily, if not hourly, basis but am often uncertain as to the true cause. Plants respond to so many environmental factors, and often at very differing rates, so definitive answers are not always possible.

There are still around six per cent of gardeners, according to research, who maintain climate change is a myth. The rest of us do know something is going on, but find the subject confusing so maybe it's time to round up what the scientists and commentators are saying about climate change and gardens.

Looking back over this summer I will start by listing those things I am sure owe much to our changing climate. The grass everywhere looked bleached out and powdery mildew was a real problem, on our roses for the first time and bergenias as well as aster. Our summer flowering plants, including the meadow, performed early and fast leaving us with a late season dearth of colour (dahlias being the honourable exception).

There was definitely a distinct lack of ladybirds and, unless I am mistaken about timing, there appear to be few daddy-long- legs about. The seasons, and consequently plants and gardeners everywhere, just seem confused and we have had everything from daffodils in November to poppies on Christmas Day.

Lastly unexpected plant deaths seem to have increased but that could always be just old age or the delayed effects of weather in the past. Trees sometimes take a long time to noticeably react to conditions.

This fits in with the general consensus on the effects of climate change, with four categories standing out.

Seasonal confusion — when plants awake from their winter dormancy, when they flower and when they fruit is changing with consequences both for us and wildlife.

Officially spring is now on average 11 days earlier than it used to be, but in the mild climate of the south west the change is not necessarily so obvious or dramatic, hence many plants here are completely out of their natural rhythm. There is very little we can do to prevent this. What we can have some impact over, however, are planting designs.

If November daffodils look awful next to your late flowering geraniums (it's just wrong) split them up. There's bound to be other spaces and better combinations available somewhere so it's better to go with the flow, as it were, than waste time trying to stop the process or just moaning about it.

Climate extremes — unpredictable and extreme weather is having a profound impact on both our gardens and our lives in general.

Our summers are hotter and drier, with longer and longer periods of garden drought, often unnoticed by the media, only interested in hosepipe bans and rationing when reservoirs run low.

Winter flooding is becoming almost normal and many parts of the country now suffer short periods of almost monsoon like rainfall in the summer. Whether flash flooding or just continuous rain falling over a period of time is responsible, the consequences are the same.

Too much water leads to waterlogged soil and is disastrous for most plants, denying roots essential oxygen and encouraging rotting.

Interestingly, until recently garden experts were recommending Mediterranean planting as a solution to the more extreme heat of the summer, but this has largely fallen by the wayside as the winters are so much wetter.

These plants, like lavender and sage, really don't like sitting in soggy soil; I have had more damage in the garden from water logging than anything else, losing large swathes of thyme and sage through rain although somewhat ironically, my willow tunnel has suffered immensely from a lack of water, probably from the end of last summer.

Obviously extremes require a thoughtful response. Improving drainage in waterlogged areas with extra sand, for example or planting susceptible plants on mounds or in raised beds is a simple, practical answer to water logging problems.

When it comes to dealing with drought, efficient watering and water retention is key. So try and water plants to a depth of 30cm — less than this and roots will form close to the surface and dry out too quickly, more than this is a waste and may contribute to water logging problems.

As one water butt will only really water one medium sized bedding container through summer we would need to fill every available space to deal with an average garden leaving little room for the plants. Unless you can afford to build big rainwater harvesting system and tank, adding organic matter is still probably your best bet. Its retaining capacity is the equivalent of an extra 5cm of rain, enough to supply a plant with water for 20 days.

Resilience of garden plants — the stress of water logging and drought and even flowering at the wrong time increases their susceptibility to diseases, pests and competition. Lawns, for example, are a good example of this.

Hot dry summers cause them to dry out and brown, opening up spaces for more resilient weeds to take hold, or moss and fungal infections in wet conditions. Again preventative measures and good cultivation techniques are the only answer.

Pests and diseases — it's not all bad news here admittedly. Dry, hot summers should decrease the levels of downy mildew, black spot (hurrah!) and the various blights and scabs which afflict many vegetables — in fact any disease which relies on water to spread its spores.

Unfortunately this list does not include powdery mildew which likes nothing better than to attack drought-stressed plants and is not at all affected by heat, hence its current rampage.

Of real concern is the largely soil borne fungus, like Phytophthora pathogen which will increasingly thrive as a result of warm, wet winters. This attacks the roots of trees, shrubs as well as other plants.

In the West Country especially, Phytophthora ramorum, (sudden oak death) is already causing huge problems, as it produces both leaf spores which can be splashed around by rain and longer lasting soil spores carried by muddy feet, tyres and dog paws as well as by plant movement.

This means it can spread in both dry and wet conditions and is only checked by low temperatures. A few bad winters would come in handy right now.

In terms of pests, importing infected plant material is still the biggest factor, but climate change is instrumental in determining whether insects make Britain their new home.

For example termites are marching north (they've already reached Paris) as we speak, as has the Rose Jewel beetle and various moths and butterflies ready to munch beloved plants.

And last but not least the old enemy — the Colorado beetle, back in Europe after a break. Expect to see the posters reappearing!

So while I peel my Jerusalem artichokes (for the final time) you can keep your eyes peeled for stripy beetles. Happy gardening.

Read more from Torquay Herald Express

Do you have something to say? Leave your comment here...

max 4000 characters


Hot Jobs