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7 Winter jobs in the alpine garden

December 21, 2021
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If last month I shared with you some of the joys of autumn, now that December is here, I’m going to suggest some winter jobs in the alpine garden which will keep you warm and busy during these short, cold days.

Tidying up and cutting back

Tidying up

In winter it is tempting for even the keen gardener to sit back and think of the joys of the coming spring. It is human nature to turn a blind eye to the sheer untidiness of dead flower heads and stems. But to get the best out of your plants in the following season you must put some effort into tidying up the alpine garden.

Plants in pots often need tidying up too, removal of dead or mildewed rosettes from cushion plants being of prime importance. Use fine tweezers and a pair of sharp fine-pointed scissors. Dusting the affected areas of the cushion with green sulphur helps to reduce the likelihood of spread of fungal diseases.

Pruning dwarf shrubs

Left unpruned, dwarf shrubs may get out of hand and exceed the space allotted to them. It is best to prune on a regular basis when the attention of the secateurs will hardly be noticed. Also, pruning provides an opportunity to mould the shape of a shrub and to assess its value in the winter garden. Is it ‘paying its way’, and if not should you perhaps remove it and replace with something more suitable? If this is the conclusion, early winter is a good time to do it as most shrubs transplant best then.

Convolvulus cneorum cuttings

Hardwood cuttings

If you wish to increase a dwarf shrub, prunings may produce suitable hardwood cutting material. In these days of ‘instant gardening’ few bother with hardwood cuttings, but many species are quite easy to increase this way. Use growth produced in the previous season, trim at the base with a sharp knife, and remove any leaves that would be buried in the rooting medium. Line out in pots or trays of a gritty, fast draining compost, or even direct in such compost in a cold frame, water well, cover (no heat) and leave well alone. Only water thereafter if it is clearly necessary.

It is unlikely that many, if any of the cuttings will root before the following spring. Sometimes a whole season may pass; patience is a virtue! Eventually, when the cuttings produce strong new growth, you can be pretty sure that below ground root production will also be underway.  Pull the cutting gently and if there is resistance lift carefully and pot in a free-draining, loam-based compost. Keep the cuttings shaded until they are clearly well established.

Cutting back and keeping plants in bounds

Some plants, notably bulbs and cushion plants, will often look after themselves for many years. An occasional intervention may be required to prevent bulbs becoming too crowded. It may be necessary to prevent some cushions swamping less vigorous neighbours, or taking too much space. Other, more vigorous occupants of the garden, may need to be controlled more frequently and with greater vigour. Pulsatilla flowers don’t look great appearing through a mass of dead foliage of the previous season’s growth. Similarly, some rosette-forming plants flower on long stems that die off but don’t disappear of their own accord. The beautiful, easy and long-lived Crepis incana is a good example.

Cleaning and tidying the alpine house and frames

If you grow alpines under glass, late autumn into winter is a good time to clean and tidy your alpine house and/or frames. First, remove all plants in pots so that the pots and staging, with or without plunge, can be cleaned. Weeds can be removed from pots and gravel top dressing replaced.

If the pots are clay and plunged, remove the top centimetre of plunge material, along with any moss or lichen. Add a similar thickness of fresh plunge material.  Now replace the pots, making sure there is good contact between pot and plunge In the case of plastic pots standing on the staging or in a frame, I remove them and sterilize the standing or gravel base with hot Jeyes fluid. I then leave for a few days to allow the toxic fumes to disperse before replacing the pots.

Cleaning the glass

If you have used a paint-on shading compound to prevent scorch damage during the summer, now is the time to remove it. You want your plants to be exposed to as much sun as possible during the long, murky winter days. Hot soap and water do the trick. If the glass is less than sparkling on the inside, you may wish to clean that too.

Keeping the air moving

Cold, damp, stagnant air provides the worst possible environment for alpines. Except in the most inclement of weather, open the alpine house doors and ventilators, and frame lights. A small electric fan can help to keep the air moving on the worst of days. I am assuming here that you will not be heating your alpine house or frames appreciably. But you may grow some plants that might succumb in a severe frost. A thermostatic electric fan set to just above freezing can save a lot of worry on a particularly cold night!

Other winter jobs in the alpine garden

Providing winter protection

While most alpine plants will survive the worst that the winter weather can throw at them, some will not. Often it is not so much cold temperatures per se that bring about the demise of sensitive plants so much as a combination of cold and wet conditions. In many cases this relates to the ecology of the plant in its natural habitat. Many alpines growing at high elevations are reliably covered with a warm blanket of insulating snow through the winter. They lie dormant and protected from icy winds and the perils of alternate freeze and thaw. Not so when they are grown in temperate lowland gardens where snow, if its comes at all, is likely to depart as swiftly as it arrived.

Plants with hairy foliage are particularly prone to rot under such unpredictable winter climate variations. Unsurprisingly, they can not use the excess water in their dormant state. Nor can they shed it in the way that less hirsute plants can. So it is prudent to provide some sort of cover for hairy cushions during the wettest, coldest months. This can be a pane of glass or plastic sheet forming a roof held in place by wire supports. Or an ordinary garden cloche if space allows. Make sure there is good ventilation between cover and plants.

Of course, it is much easier to provide protection for plants grown in pots than for those in the open ground. A simple garden frame will suffice if you do not have a glasshouse.

Creating and remaking alpine beds

Time is always short for gardeners in the growing season and major tasks like creating or remaking alpine beds tend to be postponed. The occasional calm dry days of winter provide opportunities to do such jobs in the alpine garden without distraction. And very satisfying work it can be, provided due attention is given to planning and the necessary tools and materials are to hand (see the relevant sections in my AGS Beginner’s Guide).

Providing adequate drainage is crucial as very few alpines will tolerate poorly drained soil, let alone winter waterlogging. If your underlying soil is impermeable clay consider building raised beds, rather than struggling to improve drainage. You may perhaps be put off by the amount of soil required to fill such beds, and the effort needed to move it. Remember, this is a one-time only expenditure, and on a cold winter day the effort is good for you!

Remaking a bed offers you the opportunity to make changes, perhaps replacing plants that have previously failed to prosper. Or maybe improving their positioning now that you know what they are capable of. And grouping plants in a more pleasing way in relation to form, growth rate, size and flower or foliage colour. You may wish to increase or reduce the amount of rock that you use, or its positioning. Perhaps a crevice garden would show off your alpine plants better than a traditional ‘lumpy’ rock garden. There is an excellent AGS guide to crevice gardening by one of the leading exponents of their design and construction. (see below)

The Crevice Garden and its Plants - Revised edition Product This is a revised and expanded edition of the AGS guide to building crevice gardens and the plants to grow in them.  The text has been updated and the...
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