Winter protection
Top tips from our silver-tongued founder
Winter Protection
Winter wrapping: it’s a subject about which we have to admit to some agnosticism. Do we really want to look at a cylinder of chicken wire filled with dead bracken in the middle of the garden for the entire winter? Or even worse, the beloved exotics wrapped up in bubbly plastic and brown tape?
The art of wrapping exotics to get them through winters that they were never designed to get through is still in its aesthetically displeasing infancy. We’re often asked how to wrap plants for the winter as if there are established rules surrounding the subject. Sadly, there aren’t; current wisdom seems to surround edibles only, not exotics. Therefore, wrapping is mostly down to your own ingenuity, your desire to do it, and your knowledge of the plant. Horticultural fleece is a versatile defence method and depending on your garden’s situation and how well you employ it, gives lots of plants a good level of protection. We use it in our polytunnels over winter and we also sell it:
Below are some further ideas and observations drawn from our own experience over many years.
General Tips
The object of the exercise is to give your vulnerable plants some protection from our cold, wet winters. Many plants will be fine as they will have adapted to cold conditions and can either weather them, or will come back again in the spring. So you need to know which are the plants that may need your help, and then like any good Boy Scout, be prepared.
In the early autumn, gather together the materials that you will need, things like horticultural fleece, hessian sacks or fabric, maybe straw or dry bracken.
These are our workhorses, they breathe, they insulate, they come off without leaving a mess. Use natural materials where possible because they allow some ventilation. Straw and hessian sheets are best, and horticultural fleece is good, but never use plastic as it will hold the moisture inside and cause the poor thing to rot due to a lack of ventilation. Straw is a superb insulator if you can obtain it, and like the look, and the same applies to the natural look of dry bracken.
There is no need to look at a messy garden either. A little ingenuity goes a long way. Neat white columns of horticultural fleece can add a ghostly look to the winter landscape, alternatively, over-wrap the pillars with rush matting to minimise the spectral look. Upturned terracotta pots or old chimney stacks look fine placed over the smaller wrapped plants with a tile placed over the water hole. For the dedicated, you can start weaving beautiful rush and straw caps, and for inspiration look to many other countries, as in the Mediterranean or in Japan. If you need to bind and tie, use soft webbing or jute and keep metal off bark.
You’ve got to be a bit of a meteorologist to do this, but wrap according to the weather forecast and not the calendar. Some winters are so mild that wrapping isn’t necessary. As the climate keeps shifting, we often now have a mild December, so that will need nothing from you but watchfulness. However plants will be preparing to grow long before we can see the signs, so a late spring frost will have a much greater effect than the same degree of frost would have had when the plant is fully dormant.
Get to know your garden too – Where are the warm still spots? Where are the corners where the wind blows? Cold air can act like water flowing downhill from a high, breezy plot and collecting in the valley bottoms.
Brick and stone can act as radiators, with the south and the west walls absorbing the heat, holding the day’s warmth and then gently returning it by night.
Be very aware of pots. The volumes of soil and roots within the pots are relatively small so will freeze faster than would the roots if they were in the soil. Grouping them helps, moving them for the winter to a south- or west-facing wall, raising them from the freezing earth on pot feet, and wrapping the containers as well as the plants.
Be prepared to wrap when it’s about to get cold and unwrap it as soon as that cold snap is over. However tempting, don’t leave plants wrapped up for too long, it’s a balancing act. The air trapped inside the wrappings will be cold and probably damp so that if you wrap up a Cordyline in October and unwrap it in April, some of the leaves will have rotted and it will be a dead and smelly mess. Protect the growing point with lots of layers – think string vest. Protect the root zone for plants in pots. Steady anything that might rock in the wind. Shake snow from fronds and broad leaves before a hard freeze cements it.
Specific plant types
Dicksonia antarctica
There’s no point tying up the fronds of your Dicksonia antarctica as they always look so tatty when you unwrap them. If you follow the method used at Nymans Gardens, leave the unfurled fronds for additional winter theatre (you never know – it might snow) whilst wrapping the crown in fleece to protect the development of emerging new spring fronds. Or go the whole hog and cut the fronds off and wrap the crown and trunk in layers and layers of hessian or fleece. Short of a catastrophic winter you will be delighted to see hints of a new crown of fronds emerging when you remove the winter protection. Some people say they’ll benefit from having straw in their crown. We find the evidence for this inconclusive, but one thing that does work is to build a stack of straw bales around each plant. We actually used to do this at the nursery, but it resulted in that part of the garden looking like a farm yard for three months every year – and can you still get small straw bales anyway?
Musa basjoo
Cut the leaves off once the frost has got them and protect the trunk by whatever means you have at your disposal. Wrapping in fleece from head to toe is worth doing just to preserve the trunk. A very cold winter will cause the trunk to collapse due to the plants large cell structure and the water contained within them. Using straw bales build closely around a grove of Musa basjoo undoubtedly works.
Cordylines
Tie the leaves of the Cordyline up into a cone – if you can reach them. The old leaves will go some way towards protecting the tender growing points. Sticky tape or brown packing tape works well.
Phoenix canariensis
gaffer tape is the only thing strong enough to hold a Phoenix canariensis all together. Once it’s in a column, try wrapping it in layers of fleece and more gaffer tape. The result: an ugly, white column. You can buy rush matting quite cheaply; applying this around the fleece provides an aesthetic advantage.
Smaller, herbaceous tender exotics
Knowing the origin of your plants is not only interesting but really useful. We are fortunate in having a mild, maritime climate so we can grow plants from all over the globe, but of course, some are more resilient than others.
Echium pininana, Echium fastuosum and Geranium maderense come from the Canary Islands. Melianthus major originates in South Africa while Hedychiums began life in Asia. The Cannas, though they are now naturalised over many tropical and subtropical regions, actually hail from South and Central America.
Geranium maderense is perennial, but really only a plant for very mild gardens. Echium pininana is herbaceous and biennial, so while it is worth wrapping it and hoping for a warm winter, you may lose it, but the drama of that first season still makes it worthwhile. Encasing in fleece is a useful exercise for Echium fastuosum and Melianthus major but as they are woody, there is more of a chance that they will produce new growth even after being damaged by frost.
Plants like Hedychium and Canna, will either need lifting and storing in frost free conditions over the winter, or cutting down, covering with great mounds of mulch and taking their chances.
As always, talk to us for help and advice.
Olives & citrus
Think of an olive grove on a sunny Tuscan, Greek or Spanish hillside. Plant your olives in the sunniest position that you can, make sure that the drainage is as sharp as possible and they are surprisingly resilient. Anyway, it’s virtually impossible to wrap a big tree. They may drop a lot of leaves, but almost always produce more.
Citrus need more care. Of course it all hinges on where it is that you are gardening and if the microclimate permits you may be able to keep your citrus varieties outside year round. For most of us though, the plants will need to be pot grown, so that they can have a winter under cover in a cool, bright and well-ventilated greenhouse or conservatory, and don’t forget, almost no watering until the spring comes again.
Hardy vs tender palms
Trachycarpus fortunei is a high altitude mountain plant from southern India, China and Japan, so it can easily manage the cold in the south of England with protection. Tying up the fronds can help to prevent physical damage if heavy snowfalls are forecast.
The same follows for Phoenix canariensis but this palm will appreciate some protection, particularly the smaller specimens. In the Mediterranean winter, you will often see the fronds tied up in a pointed bundle and sometimes, this is then swathed in straw matting to create a fantastic garden sculpture. This both protects the growing point, and saves the fronds from thrashing about and being damaged in the winter winds. It also makes it easier to wrap the whole bundle in fleece or hessian. We don’t use straw. We would advise you to protect with additional fleece scraps.
Chamaerops grow happily in the Mediterranean and are often seen flourishing in mild UK gardens. They like sharp drainage, they don’t like winter wet, and they hate being dripped on. If in pots, they can be moved to a sunny and sheltered spot, so that the foliage lasts the winter in good condition, though they readily produce new leaves to replace tatty and damaged ones.
Butia are a bit more vulnerable. Choosing a prime spot in a sunny, well drained soil is half the battle but these too, may do better in pots so they can be moved into dry winter quarters. If they are planted, then building a tent with canes and fleece, or wrapping the leaves may give them the edge.
Agaves & other succulents
Agaves and succulents have evolved to live in deserts so while large fluctuations between hot and cold temperatures won’t phase them, they are used to dry soils, and our cold, wet winters are a problem. Plant in fiercely gritty soil in the sunniest possible spot and ideally in the rain shadow at the base of a warm wall. Alternatively, grow them in pots and move them under well-ventilated cover, so the winter rain doesn’t sit in the rosette. Also, remove saucers until spring.
Proteaceous plants
Grevilleas and Lomatias are self-sufficient and tough little plants. They like good drainage, rainwater and poor soil. Don’t be kind to them – feeding will kill them and they hate chlorinated water. They have almost all evolved to flourish in the poor, sharply drained, acidic soils of the fynbos of southern Africa. Think sandy, heathland, Mediterranean conditions.
After the cold: patience, then precision
Resist the tidy impulse in February. Much that looks lost will stir in April and May. Use your thumb to give a gentle scratch test along the stem to see if the bark will lift easily as green cambium means life.
On palms, a careful spear-pull test tells you whether the central growth is firm. If a Cordyline is wet and soggy in the crown, don’t despair. They can undergo major surgery even to the point of cutting though the whole trunk to where there is sound tissue or even right down to the ground, and then be patient while it regrows.
In early spring bananas can be cleaned off until there is solid material and left to reshoot.
When the night minimums steady at six to eight degrees, you may begin light feeding; major shaping waits until growth is convincingly underway.
Pots, roofs and windy plots
Pots are wonderful – it keeps the garden mobile and means that individual plants can have the winter protection that they need. But remember, roots in containers are vulnerable to the cold so in the winter, group the pots together, mulch the surface of the soil, (not forgetting to leave a clear ring of air around the trunk/stalks of the plants,) and then wrap the pots to insulate the soil and the roots. Frozen soil stops plants from drawing water through themselves, which means that the plants are then vulnerable to desiccation by the winter winds. In very windy positions wrapping the plant loosely can minimise the effect of the wind. Steady anything liable to rock and watch irrigation – dry compost chills faster and deeper than evenly moist compost.
A last word on taste
There is a line where necessary protection becomes seasonal farce. Our view is simple: protect what needs it, for as long as needed, with materials that let plants breathe and emerge unblemished. Then take it all down promptly and let the garden look like itself again. If you love our nursery, you will love your garden; the aim is to carry your collection through the cold with discipline and refined design ideals, not to turn it into a winter encampment.
Please download our Winter Protection PDF to help you navigate the colder months of the year.
Further help and Guidance
We’re always happy to help with queries over the phone or by email if you can’t make it down to us. As always, feel free to get in touch if you have any questions or concerns.