Casualties of Cold

I got a chance for some time in the garden yesterday, although it is still cool (8-10°C; 46-50F).  With the extreme cold this winter I was sure we’d lost a lot of plants.  You see, with a relatively large garden (30ft x 200ft) we were given a generous wedding present of gift vouchers for a specialist nursery.  We set about landscaping what had been a mature but undeveloped space, and used the vouchers for some unusual shrubs to dot around the edges of the lawn and vegetable patch. That was many years ago now.

With December 2010 daytime temperatures down to -5°C, and as low as -13.7°C recorded one night I did wonder how much I could trust our outdoor sensor. How many of the more sensitive plants have survived and what does this say about temperature?

Plant Hardiness

This is discussed differently in Europe, the UK and US, with a useful comparison here.  There is also an article Evaluating plant hardiness published by the Royal Horticultural Society:

“UK winters tend to be relatively mild: extreme subzero temperatures of -12°C to -18°C over large parts of the country only happen occasionally. Recent extreme winters were those of 1940, 1947, 1963, 1979 and 2009–10 [now also 2010-11].  Every 20–30 years seems to be the pattern, global warming notwithstanding.  I am not sure how useful such winters are in assessing hardiness, as they only come along once in a generation. If a plant survives 29 years out of 30, should it be considered hardy?”

Dead as a doornail

Abutilon vitifolium

Pictured here in its prime in 2006, this one was a risk. We managed to grow it to about 12ft, and it used to put on a spectacular display in May which I could see from the kitchen window. In the last three years it did not like the cool wet summers and colder winters, despite being in a sheltered spot. Now dead!

Hardiness:  the book says “hardy to -5°C” but likes well-drained soils (our’s isn’t).

 

Ceanothus arboreus (Californian Lilac)(Image source: http://www.rhs.org.uk)

I loved this for its penetrating blue colour flowers in Spring.  It survived Winter 09/10 (-8°C) with a lot of damage, but there is no hope this year – brown leaves, brittle stems. We’ve already cut it down; now we just need to dig out the stump.

Hardiness:  the book says “hardy to -5°C”. Mostly hardy in the UK, but can be damaged by frost and wind in exposed situations. Yeah!

 

Lebanese shrub

I wish I could remember the name of this shrub.  I only remember it was Lebanese (or perhaps Syrian). I didn’t think it would survive the wet but it thrived and grew to about 7ft in a sheltered spot, even surviving last year.  It had the sparse look of a plant suited to dry soils – tiny leaves covered with silver down on the underside and small flowers. Now it is brown and crispy, with no sign of green life under the bark.

 

Cordyline australis (Cabbage palm)

A slight cheat – this is in my parent’s garden, not far from the coast.  This was fully mature when we moved there 30 years ago and lost perhaps the odd trunk in the coldest winters.  This year skeletons of mature trees are a common sight. Mature plants are common as ornamental plants in coastal regions in milder parts of the UK; common names include Torquay/Torbay palm, or Cornish Palm.” Hardiness:  the book says “hardy to -5°C” but from previous years I’d say more than that.

 

Looking very sad

This spurge has been cut back more than I’ve ever seen it. One plant does have some life at the base but the one in a more exposed location looks decidedly ill. Hardiness:  Book says “hardy to -5°C”

Euphorbia wulfenii ...now

...in Summer (Image source: http://www.gardenersworld.com)

There may be hope

Phormium Tenax (New Zealand Flax)

(Image source: http://www.rhs.org.uk)

This had formed a huge clump 6ft x 6ft and each summer sent up 3-4 flower spikes.  It is now a thigh-high heap of dead leaves.  The photo shows some colour on a still-fleshy leaf near the middle of the clump.  Here’s hoping. Hardiness: the book says “May tolerate temperatures of -12°C if given a deep dry mulch”.  We didn’t, but I guess there’d be some protection from the outer leaves – and the snow itself.

Grevillea rosmarinifolia (Image Source: http://mikesgardens.blogspot.com/)

This is the strangest plant in some ways. In some years it will try to flower in January; in fact I have seen it trying to flower in many different times of the year. It is spiky and unruly and tries to invade our preferred patch for sitting in the sun, but I do hope it survives.  Now every single needle-like leaf is scorched, but it nestles in a ‘cove’ formed by dense foliage and perhaps will regrow from the base.

Hardiness: the book says “some will survive to -7°C if wood is well-ripened in the summer.”  Fingers crossed.

 

Cosmetic Damage Only

Eucryphia 'Nymansay'

Fabulous in August (flowers ~2.5 inches diam)

I’d never heard of Eucryphias until we planted one.  They are handsome evergreen trees, tall and columnar in shape;  in late summer the blooms are covered in bees. They’re from Chile I think. I’m glad to say ours is now 17ft and has only suffered some scorching to lower leaves.   Hardiness: one book says intermediate between (UK) H3 (= FH) and H4 (= H); another says “*** (Borderline)” where *** is “Hardy to -15°C”.

Drimys lanceolata - stripped bare

Lower leaves scorched

A Tasmanian plant, which I just found out is called the Mountain Pepper, this is such a handsome plant with red stems and dark evergreen leaves.  It has the most wonderful, aromatic properties; apparently the berries can substitute for pepper or allspice. This plant has aways tended to be damaged by frost, but usually only the outermost leaves.  Given previous years’ experience we really didn’t think it would survive this year, but we were wrong. Both the upper and lower parts of the plant have suffered damage, but the core of the bush is still healthy.  Hardiness: the book says “frost hardy to -5°C”; from the placement of the temperature sensor, and the other plants which died (or survived) this plant has survived at least -10°C.

Embothrium coccineum, Chilean Flame Bush (Image source: Wikipedia)

It had taken us ages to establish a Chilean Flame Tree – apparently they can’t tolerate soils rich in phosphorus. Our young tree is now about 12 years old and flowers spectacularly every May. 

Hardiness: according to Wikipedia “The leaves are evergreen, occasionally deciduous in cold areas…” I found a website specialist in Patagonian plants that says hardy to -10°C.  We’ve certainly never seen such a great loss of leaves before as compared to this year. It still looks alive, just a bit pathetic. I guess I’d be fairly confident this one will recover.

I guess this all says more about the plants than anything certain about the temperature.  Yes, a few surprises and some where the jury is still out.  Now if we were to have a run of cold winters it would be interesting to see what survives.  I got used to gardening in recent warmer times and was able to grow tomatoes (although cold tolerant varieties) outside for a few years, but the last two last summers were a disaster – green tomato chutney was about the height of it.

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13 Responses to Casualties of Cold

  1. gallopingcamel says:

    That winter of 1947 was unforgettable. In south Wales the cold started in mid February and persisted to the end of March. The snow drifts were over six feet deep in Pembrokeshire, a county that has such a mild climate that palm trees can grow.

    In contrast to the cold winter of 1947, the summer was exceptionally hot so I spent most of July and August on the beach at Tenby.

  2. gallopingcamel says:

    Like you, I used to grow tomatoes and always got a fine crop at least in terms of quantity. The problem was that in three years out of four very few ripened properly. As I hate wasting anything I made copious quantities of green tomato chutney in the “off” years.

    Something similar with “Runner Beans”. I would get a decent crop every year but roughly every fourth year the crop was huge so I salted the surplus.

    When I moved to New Jersey, everything grew in unbelievable profusion. One year I planted Zucchini and “Egg Plants”. I was so overwhelmed with produce that I ended up giving 95% of it away. Tomatoes were hopeless in New Jersey as there was too much sun for my favourite varieties that ripened too early and then split open. The varieties that grew well produced huge tomatoes that lacked flavour.

    • John F. Hultquist says:

      There is no justification for planting Zucchini. If you want a big one to stuff and bake, okay, but still – why bother? You can stuff an old shoe to much the same effect.

      Instead, plant the yellow summer squash (some call it yellow Z.). People will actually accept these when you offer it to them. They will give you things from their garden in return. They can be eaten raw or sliced and fried. As a young farm child in the early 1900s, my mother and her sisters would use the “straight-neck” yellow squash to dress up as baby dolls. When my grandmother would slice and fry such squash the children would claim they were eating “fried baby.” One-hundred years later, we still eat fried baby!

      • Verity Jones says:

        Nonsense! Zucchini (courgette) is fabulous – eat young and just don’t let them get more than 5-6 inches long. When we have a glut I make a courgette and lime frittata. Grated courgette – squeeze out the water and fry on low heat in oil/butter. Add greated lime zest and juice. Sometimes I add corriander (cilantro) leaf. Add cubed cooked potato (occasionally ham or cooled bacon also) and pour beaten egg over. Finish as normal frittata.

  3. John F. Hultquist says:

    While an interesting post, our temperatures here in central Washington State frequently will reach minus 25 C, sometimes lower. This winter it made it to minus 20 C. The plants you show are unknown here.

    My thought on a green tomato; toss it into the compost heap. Just because you can make green tomato chutney doesn’t mean you should.

    Just under your chutney comment, the auto-insert feature has placed a “Food Press” ad showing a ‘raspberry trifle cake,” and although the directions and making of such seems a bit of work, it all looks and sounds delicious. Raspberries thrive nicely where winters are cold and I still have several pounds in the freezer. We took some to friends house this morning and had them on waffles.

    Moral: Plant some raspberries!

  4. tonyb says:

    Verity

    Very nice post which surely touches on something staring us in the face-that plants are an accurate reflection of a changing climate.

    We had a glorious weekend here, with temperatures on Sunday up to 14.5C-a little surprising as the MET office not 15 miles away in Exeter had told us it would be overcast and 11C. A bonus for us, but the forecast would have put many tourists off coming here to the detriment of local traders.

    Its interesting that you write on plants as I had been contemplating writing an article on ‘plants as a temperature proxy’ (following hard on the heels of my never to be forgotten ‘fish as a temperature proxy’ 🙂 )

    As a gardener living on the South West coast of Britain 100 yards from the sea I have observed a change since we moved here 10 years ago;

    The first five winters were typified by many plants flowering throughout-in fact I kept a record of them. This included geranium and fuschia, mock orange and many others. Our succulents also flourished.

    The last three winters have been a different kettle of fish. Very few plants have flowered, our geraniums have been frozen to a pulp, fuschias stripped back, echiums destroyed. We have lost several Torbay palms (we live 7 miles from there) and many succulents are gone. Many of these plants were well established, others we bought when we moved here.

    This latter category of succulents is interesting, as several of them were bought by us a few years ago from St Michaels Mount in Cornwall-just about as far south and protected as you can get.

    We have had to make a journey to get some more from there on each of the last three years and the island’s stock is dwindling as their plants have also been cut back each year by the weather.

    Hadley themselves record this sharp drop in temperatures over the last five or so years;

    http://www.metoffice.gov.uk/hadobs/hadcet/

    As I have mentiioned before the Mean Average CET in 2010 at 8.83 was identical to the first year of the record in 1659.

    The interesting thing about all this is that the BBC have a great programme called ‘Farming today’ which is an AGW free zone. In recent months we have had farmers on saying they are abandoning crops they have been encouraged to grow by Govt to reflect our new Mediterranean climate. (HAH!)

    This has included Apricots and walnuts amongst other crops. So the weather is telling us things-it is getting colder in some parts of the world including ours. This is no surprise to either of us of course as we produced ;
    https://diggingintheclay.wordpress.com/2010/09/01/in-search-of-cooling-trends/
    showing counter cyclical cooling trends.

    We took a genuine 30 year trend for our study. I dare say if we were to look at 5 or 10 years we would see many more areas bucking the warming trend and giving the lie to the ludicrous ‘global’ temperature when we are assured we have just experienced the ‘warmest year ever’. If you live in an urban area in some parts of the world perhaps. For many of the rest of us our plants and crops are telling a different story.

    Might it be worth combining your observations and mine, together with any others that are posted here, and mould them into an article for WUWT asking readers for actual evidence of what crops/plants locally are telling us? If the reaction is interesting I would be happy to subsequently draw the resultant data together for a more scientififc analysis.

    In case you think it might be useful I have picked out a few examples of historic climate change-warming and cooling- in chronological order where there is a reference to plants-sorry for the length of this post;

    1) Saint Cyrian was Bishop of Carthage around 250AD. He was talking
    about the huge increase in Rome’s population which had caused wars against
    Carthage and the building of 500 towns in North Africa to satisfy the eternal city’s
    ever increasing needs for timber, cereal, and exotic animals for its gladiatorial
    contests. Here is an account of lack of sustainability and climate change caused by a
    variety of factors, with the hints of a decline in the warm climate that had sustained
    Rome now starting to work against them as it intermittently turned cooler;
    ‘The world has grown old and does not remain in its former vigour. It bears witness to
    its own decline. The rainfall and the suns warmth are both diminishing. The metals
    are nearly exhausted the husbandman is failing in his fields. Springs which once
    gushed forth liberally now barely give a trickle of water.”

    2) Around 1560 the Rev Schaller, pastor of Strendal in the Prussian Alps (in an eery echo of St Cyrian) wrote;
    “There is no real constant sunshine neither a steady winter nor summer, the earth’s
    crops and produce do not ripen, are no longer as healthy as they were in bygone years.
    The fruitfulness of all creatures and of the world as a whole is receding, fields and
    grounds have tired from bearing fruits and even become impoverished, thereby giving
    rise to the increase of prices and famine, as is heard in towns and villages from the
    whining and lamenting among the farmers.”

    3) “Over the fifteen years between 1720 and 1735, the first snowfall of the year moved from the first week of September to the last. Also, the late 1700s were turbulent years. They were extremely cold but annual snow cover would vary from ‘extreme depth to no cover’. For instance, November 10th 1767 only one snowfall that quickly thawed had been recorded. June 6, 1791 many feet of snow in the post’s gardens. The entry for July 14, 1798 reads ‘…53 degrees colder today than it was yesterday.”

    4) This comes from the extensive weather records of Thomas Jefferson; the warm weather of the early 1700’s has given way to intense cold then another period of warmth
    http://xroads.virginia.edu/~HYPER/JEFFERSON/ch07.html

    “A change in our climate however is taking place very sensibly. Both heats and colds are become much more moderate within the memory even of the middle-aged. Snows are less frequent and less deep. They do not often lie, below the mountains, more than one, two, or three days, and very rarely a week. They are remembered to have been formerly frequent, deep, and of long continuance. The elderly inform me the earth used to be covered with snow about three months in every year. The rivers, which then seldom failed to freeze over in the course of the winter, scarcely ever do so now. This change has produced an unfortunate fluctuation between heat and cold, in the spring of the year, which is very fatal to fruits. From the year 1741 to 1769, an interval of twenty-eight years, there was no instance of fruit killed by the frost in the neighbourhood of Monticello. An intense cold, produced by constant snows, kept the buds locked up till the sun could obtain, in the spring of the year, so fixed an ascendancy as to dissolve those snows, and protect the buds, during their development, from every danger of returning cold. The accumulated snows of the winter remaining to be dissolved all together in the spring, produced those over flowings of our rivers, so frequent then, and so rare now. “
    (from observation 1772 to 1779)

    5) Our modern bouts of apparent short memory regarding previous climatic conditions
    can be seen to be nothing new by reading the comments from the annals of
    Dumfermline Scotland from 1733/4, when it recorded that wheat was first grown in
    the district in 1733. Hubert Lamb wryly observes that was not correct, as enough wheat had been grown further north in the early 1500’s to sustain an export trade

    6) That the temperature dropped from the start of James Hansen’s’ famous Giss record in 1880 places it out of context to the warmer period that preceded it, and this is reflected in this intriguing reference from the records of the Canadian Horticulturist
    monthly of 1880 (page 7).

    “I do not know whether or not the climate of Ontario is really becoming
    permanently milder than formerly, but I do know that for the past 18 years or 20
    years we have not experienced the same degree of cold as the seven years
    preceding.”

    7) Coming back towards the modern era this is what a farmer from Buchan in North East Scotland, one of the snowiest parts of lowland Britain, wrote in the agricultural section of the local newspaper during the exceptionally mild winter of 1933/34.
    “1934 has opened true to the modern tradition of open, snowless winters. The long ago winters are no precedent for our modern samples. During the last decade, during several Januarys the lark has heralded spring up in the lift from the middle to the end of the month. Not full fledged songs but preliminary bars in an effort to adapt to our climatic change”
    It then goes on to say;
    “It is unwise to assume that the modern winters have displaced the old indefinitely”
    and also;
    “Our modern winters have induced an altered agricultural regime”

    Tonyb

    • Verity Jones says:

      Tony,

      Don’t apologise – keep collecting and documenting such gems.

    • gallopingcamel says:

      tonyb,
      As you point out, agricultural practices recorded over the centuries have much to tell us about climate.

      The History Channel put together a video called “Little Ice Age, Big Chill” full of inconvenient truths about climate changes in the recent past. For example it links “Age of Revolution”, the “Black Death” and our drinking habits with climate. Here is a link to a preview. The full 90 minutes can be downloaded from a variety of sources of questionable legality or you can buy a DVD from the History Channel.
      http://www.veoh.com/browse/videos/category/educational/watch/v158890018kQaxQaK

  5. John F. Hultquist says:

    The timing of “cold” is important.

    I have Black and Carpathian walnut trees. Early last April (2010) we had two days of temperature several degrees below freezing. The trees had leafed out and all leaves on two dozen trees blackened and dropped. Secondary buds then produced a new canopy a little less than the first. A few nuts were also produced. This year, even though January was warm*, it has been sufficiently cold since, that the trees have not yet shown any sign of growth.
    ———————————–
    * http://www.wrh.noaa.gov/climate/temp_graphs.php?stn=KYKM&submit=Change+Station&wfo=pdt
    This chart is for a town 40 miles south of us, at the northern end of a fruit and vineyard area that stretches to the southeast.
    ———————————–

    Vineyardists in the area SE of Yakima have been inspecting the buds on their vines. Some growers with vines in the lower valley think most buds have been killed. The extent of the loss is not yet known. The cold air pools in the parts of the valley toward its southeastern end because of the topography. Use Google Earth and put — Benton City, WA – in the “Fly to” box, and have a look. The Yakima River brings irrigation water from the Cascade Mtns. and generally flows toward the southeast. 30 kms. west of Benton City the direction of the Valley changes and the river flows to the ENE, then there is a complete topographic block and the river turns north and works its way around Red Mountain (vineyards here are east of the river and south of the ridge). Zoom out from the local Red Mtn./Benton City view to a regional scale and you can see the larger up-fold in the land and that Red Mountain is the eastern end of it. Cold air drains off the mountain, into the valley and then its only escape is through the narrow river canyon going directly north. Vineyards on the slopes of the more western parts of the valley have the cold air drain off of them. There is one at these coordinates:
    Taken from Google Earth: 46.457911, -120.293932
    This small area is the highest block of vines planted by folks here (46.425047, -120.293834). http://www.bonairwine.com/
    Temperatures on these higher on-slope lands will be several degrees higher than farther down the valley.

    The killing cold came in early November with little earlier cold. The same temperatures six weeks later would have likely found much hardier vines had the temperatures dropped more gradually. Irrigators have learned to withhold water as soon as they are sure their fruit will ripen. Usually this works well. So, the grower’s knowledge and practices are also important. If you can’t control your water supply then the plants will stay green well into fall and be more susceptible to cold.

    Wine grapes would be an excellent study as the same sorts of plants are grown widely around the world and the growers keep track of weather on a regular basis. Growers also push into all the extremes of latitude and elevation.

  6. jheath says:

    I had a beauty Ceonanthus from 1999 to 2008 here in North Yorkshire. It went in the 2008/9 cold spell. I tried a new one nearby and that went in 2009/10, and then again I tried and again it has gone. Time for hardier plants for the next few years! Back to the 70s when I did not grow ceonanthus?

    • Verity Jones says:

      Exactly. Back to the 70s. I have an old gardening book from the late 60s. I think it is about to become very useful again.

      Just thinking back on that palm in my parents’ garden. It was mature when we moved there in the mid 80s. It may have been planted after 1947 – that would tally with the age of the house, but also from its size it could be post-1963. There were some dead limbs, perhaps from the cold winter of 1978-79.

  7. John F. Hultquist says:

    Nonsense! Dump the Zucchini, add a bit more potato, chopped red pepper, and chopped mushroom. Fabulous.
    I hold an equally strong disdain for Okra.

    I do agree on Tonyb’s posts though. Gems.

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