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It’s a cover up – November 2018

November 27, 2018
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After more than a week of shower-laden easterlies off the North Sea, lowering skies, ever-shortening days and sodden leaves, we are into full late-autumn sog here.

On the rare occasions that the sun shows its face, it scarcely peeps above the horizon, elevated on this northern slope, and in our sheltered position, even the dreich wind has little influence on the all-pervasive moisture. Given also that we sit on a cold heavy boulder-clay soil, it is scarcely surprising that many subjects tend to rot over the winter months.

As a consequence, I have tended to cover susceptible subjects in the garden over many successive winters using a wide variety of techniques, many of them rather Heath Robinson, as befits my rather impracticable nature. For many years I tended to group susceptible subjects and then cover them for four months with large framelights covered with polypropylene sheets. These were then held in place with roof-rack ties. Over the years, the frames have tended to rot, as indeed have the ties, and I found that the rather large covered areas tended to become stagnant, and even rather too dry. Latterly, this practice has fallen into disuse and I have used smaller covers, often propped on top of fridge baskets, bakers trays and the like (I told you it was Heath Robinson!).

This year, given a rather large number of precious and rather damp-prone Meconopsis that have been planted out, I have attempted to be rather more practical. A local glazier has kindly cut eight 24 inch square panes of greenhouse glass into four, giving 32 foot-square panes. I have then cut some stiff wire into lengths and bent them (as in the picture below) using pliers to give acute corners.

Its a cover-up

These wire supports are then used in one of two ways. In some cases, usually when covering a relatively small plant in the open garden, the glass is slotted into one support and then rested on the soil on the other side of the plant. The prongs of the support are buried in the soil to more than half their length.

It is important that the acute corners of the wire frames are very acute indeed, so that they grip the glass (and, it follows, that the glass is quite difficult to insert; it is probably safest to wear gloves in case of breakage, although I have not experienced any so far).

For covers, cloches if you like, on raised positions, containers, troughs or raised beds, it is usually more convenient to use two of the wire frames, one on each side of the piece of glass.

This (above) is a fishbox with meconopsis seedlings, by the way. The two on the right side are M. integrifolia ssp. souliei. I find I cannot overwinter most of the monocarpic meconopsis without covers (e.g. M. punicea, M. integrifolia and relatives, M. quintuplinervia, M. superba, M. delavayi, M. henrici etc.). However, M. racemosa, M. prattii and the ‘big blues’ do not need covers.

Here is another example, this time covering Pulsatilla vernalis. The flower-buds of this tend to abort if not covered over winter.

In some areas there are now some numbers of these cloches and they do have quite an impact on the garden, but only during the darkest months when there is relatively little to enjoy in any case. It is a distraction I am prepared to put up with in an effort to grow more taxing plants which give me great pleasure.

So far the cloches have withstood one set of winter gales without any having been dislodged. The weather pattern is changing as I write and we are due another batch of gales tomorrow, so we will see. It is worth emphasising that this is a very sheltered garden and systems like this might not be as robust in an exposed site.

As noted earlier, this is not the only covering technique that is employed here. I have two panes of heavy duty glass (once in a bookcase) which I prop over susceptible petiolaris primulas, and which usually withstand gales in this position without further support.

The other heavy pane rests on an old baker’s tray above a fishbox in order to shelter a soldanella. I find that soldanella buds tend to abort without this cover. It is noteworthy that both the soldanella and pulsatilla are snow-patch plants which remain under snow-cover until shortly before they flower.

The other main problems at this time of year tend to be caused by birds scratching (and not only in the garden; two Androsace pubescens were uprooted from their pots in the alpine house yesterday, and rosettes have been pulled out of a Saxifraga pubescens cushion). To attempt to obviate this, I used wire-netting squares. My daughter found these in her garden when she moved in and had no use for them, so I expropriated them. I have no idea what their real purpose is meant to be. In this case they are protecting a precious snowdrop which is starting to show above ground. It is important that it is removed before the snowdrop elongates too much and becomes entangled in the framework.

Elsewhere, one of these netting squares has been used to support glass where this covers a container planted with some of the easier Juno irises.

I think that is more than enough on bits of glass!

On a more cheerful note, I have found, as I suspect many readers have, that it has been a unparalleled year for blossom on the winter-flowering viburnums. The V. farreri, which rarely flowers well, has been superb but is now over. The V. x bodnantense is also slightly past its best now, although I am sure there will be another display in the early spring. It has been magnificent.

Viburnum x bodnantense 'Dawn'

I am closing with a major standby in this garden, Celmisia allanii. There is a large and long-standing mat of this growing in some shade, which has proved a useful stock plant. Dutch cuttings torn from the plant (with a bit of root) almost invariably grow away if pressed into a raised, moisture-retentive position and they make a brave show in the gloomy autumn light.

Celmisia allanii


Image of John Richards John Richards

John Richards has lived in south Northumberland for 50 years and has been a keen grower of alpines, and visitor to the mountains, throughout the half-century. He and his wife Sheila have been in their present garden 30 years and John has been writing this diary about the garden since 2006.

John is Emeritus Professor of Botany at the University of Newcastle, where his research interests centre on the evolution and genetics of plant breeding systems. He is an authority on the genera Primula and Taraxacum (dandelions!). John is an AGS judge, exhibitor and Vice-President and previous President (2003-6).