Winter Gardening Tips

January - February

Hopefully your tender garden plants have been put to bed, either in a greenhouse or tunnel, wrapped in fleece, especially those in pots to protect the roots.

Tubers of dahlias and tender bulbs should have been lifted and stored in slightly moist compost then covered in fleece or blankets.

Very tender exotic plants should be in the house or conservatory but remember - a lot of plants need a chilling period in order to rest and in some cases to fruit. In the case of citrus a winter low of about +10 degrees is ideal.

Tip: Do not use plastic or bubble wrap on tubers or bulbs as this will make them sweat

Tip: Do not store anything damaged or diseased.

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In the garden, precious plants can be wrapped in wigwams of fleece, hessian or coconut matting. You can be quite artistic, turn it into sculpture.

Branches can be wrapped in coloured cotton in the Japanese way.

Just imagine an entire tree in vivid red or blue against a snowy background - it can be very striking!

Pipe lagging may not be as beautiful but is effective around small trunks. Herbaceous crowns can be protected with dry compost or leaves, some black plastic to keep this dry and then an organic covering to disguise the plastic.

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European Hardiness Zone Average annual minimum temperatures (celsius)

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The RHS is now in the process of giving all plants a hardiness zone rating

This area is rated as 7 in the European Hardiness Zone but I think it’s bordering on 6. This will help you to know what temperatures your plants can tolerate and how to care for them during the winter.

-45.6 and below Zone 1
-45.5 to -40.0 Zone 2
-40.0 to -34.5 Zone 3
-34.4 to -28.9 Zone 4
-28.8 to -23.4 Zone 5
-23.3 to -17.8 Zone 6
-17.7 to -12.3 Zone 7
-12,2 to -6.7 Zone 8
-6.6 to -1.2 Zone 9
-1.1 to 4.4 Zone 10
4.5 and above Zone 11

Planning Ahead

This is a very good time to take stock of your year - what worked and what didn't and also to plan your next 12 months.

In our experience no two years are the same. If a new plant has not done well, give it more than one year - you never know, next year may be just what it needs. If it still fails to thrive, do not be afraid to move it to a better position.

Most plants will move well if you reduce the shock. Do it in the dormant season when the demands on the roots are low. Keep root disturbance to a minimum and plant at the same depth as before. Reduce top growth on shrubs to limit the demands in the spring surge and stake trees to prevent wind rock. Normally the best time would be autumn or spring for trees and shrubs. However in this climate we believe it is better to do it in the autumn so the plant can produce good roots through the winter in order to cope with the desert conditions of a French summer. Avoid doing any work on ground which is too wet, since too much traffic then can cause compaction which is very damaging to the soil structure.

Herbaceous plants benefit from splitting after a few years. This invigorates them and is also a good way to increase your stock.

With most plants it is a very easy process. Place two forks back to back into the centre of the root ball and pull apart - do this as many times as you need but keep good sized pieces to grow on well this spring.

If you have a very thick root ball which will not pull apart, a knife or even an axe will do it. This can be done in the autumn or spring.

Tip: The exception here are grasses - they will not reproduce roots during the winter so should always be split in the spring.

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The dormant season is also the time to plant new trees and shrubs. It is too late for the pick of the bare root trees now, but they are the best value for two reasons.

The first is that they have been grown in the ground without the restrictions of a pot so are healthier, and the second is that the grower has not had to spend as much time and money caring for them, so they are cheaper. They are generally in the garden centres in autumn but also occasionally in spring.

Container plants can be planted at any time of year because their roots are not disturbed, obviously avoiding extremes of heat, drought and cold.

Tip: All newly planted trees and shrubs need watering for their first few years.

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Winter pruning

The RHS Encyclopedia of Gardening and the RHS book on Pruning and Training are invaluable. They will give detailed advice on all types of plants. If that’s a bit too technical, just remember the golden rules - Cut out all dead, damaged or diseased growth, and anything crossing or which spoils the shape of the plant. It is very hard to kill a plant by the wrong pruning, but you may affect the flowering or fruiting and you may make it beautiful or ugly.

Identification of the plant is vital in order to know the appropriate pruning method. Again, the two volume RHS A to Z Encyclopedia of Garden Plants is the best reference book and their website is very helpful and up to date (www.rhs.org.uk).

Formative pruning is vital in the early years to give a well-balanced attractively shaped tree. If you start with a maiden whip (one strong straight stem with no laterals), tip it about 5 buds above where you want it to branch. In the second year, select the 5 best evenly spaced outward facing branches and tip those where you want them to fork. Cut out anything else on the main stem. In the third year select two strong growths facing outwards from the tip of the 5 branches and remove the rest. Other than keeping the stem and these branches clear the tree should need no more attention. It can grow on to make its own natural canopy.

Lombardy Poplar fast growing tree

Most trees are bought at about the 3 to 5 year old stage. They should have a clear stem or trunk with about 5 evenly spaced branches facing outwards.

Tip: Do not buy anything lopsided - it will never make a balanced shape.

Also beware the ‘baliveau’ - this is a very common form of pruning in this region. It involves cutting all laterals (side shoots) to within 20 cms of the main trunk to create a columnar effect. Fine if you want a fastigiate* tree but why not chose one that will naturally grow that way. It is very difficult to convert a 'baliveaud' tree to a lollipop or umbrella shape.

*Definition of Fastigiate - A tree or shrub that is fastigiate has branches that point up. Sometimes the upward sloping branches of a fastigiate tree could look like they’re part of a single column.

There are fastigiate varieties in beech (Sylvatica "Dawicks Purple"), cherry (Amanogower), yew and Mediterranean cyprus (Cupressus Sempervirens).

Example of a
Lombardy poplar

Winter Copicced Cornus

Coppiced Cornus

Pruning does seem to frighten a lot of people but it is quite simple. Think of the sap as traffic. If you cut a branch (road) in the middle, the sap (traffic) has nowhere to go, it can't return, it's a one way street. The only option is to send out lots of shoots (cars). Very useful for young coloured stems of cornus and salix or corylus (hazel) and betula (birch) when cut to the ground (don't prune the coloured stems until spring so you get the full colour affect throughout the winter). This is called coppicing. (When the stems are cut to a point on a raised trunk, it is called pollarding). If you cut the branch at a fork (T junction) the sap (traffic) has a continuing route to follow on the remaining branch (road) leaving a smooth shape, this will give you a clear and strong frame.

It is also important to recognise the difference between buds. Leaf buds are generally thin and pointed - flower buds are fat; vital if you want to avoid cutting out all your flowers for the coming year. You also need to know whether your plant flowers on old or new wood. If it flowered on the previous year you should be able to tell. Forsythia for example flowers on 1 to 2 year old wood so it's no good pruning old wood out and leaving nice new growth - you will have no bright yellow flowers in spring. Again, check your buds - are they fat or thin?

The new trend for not cutting down herbaceous foliage until spring should not be set in stone. The benefits of leaving seed heads for structure, grasses for colour, form and shelter and seeds for wildlife are huge and give a lot of interest throughout the winter. Plants deteriorate at different rates. Keep what you want for as long as you want it. If it starts to collapse or look unattractive then cut it down. It will spread the spring workload. Check the hardiness rating. Some plants need the protection of their top growth so make sure that these are mulched.

There are jobs to do at this time of year but they should not be chores - take time to enjoy the silhouettes on a frosty day; the shadows when the sun is low. This quiet time won't last long; we could be mowing the lawns in a couple of months!

One last thing, remember the birds. They are the gardeners friends. If you give a variety of different feeds you will attract a huge range of birds. Be aware that the RHS is now advising you to remove the plastic mesh from the fatballs following reports of birds becoming entangled in it.

Winter prunus2
Winter prunus1

Prunus, example of open canopy - this is 5 years growth from main stem

Prunus, 6 main branches selected the previous year then 2 strong growers selected this year from the tips