Winter Protection

In the UK we are able to grow a vast range of plants to replicate almost any planting style from around the world.

This however can cause a problem as some of our much-loved plants do not like the UK winters, this will either be down to the wet, cold or both.

When designing a garden, it is important to decide what level of protection you or your client is willing to do to keep there plants alive.

Below are some hints, tips and explanations that will help decide the best way to go about getting plants through even the worst winter weather.

Fully hardy

Fully hardy plants will require no protection in most area of the UK. Most of the plants that are grown in the UK gardens fall under this category.

This does assume that the plant has been planted in the correct location for their preferred growing conditions.

Reasons for a fully hardy plant dying can include:

  • Weakening due to disease through the growing season/winter
  • Poor soil conditions (drainage/dry)
  • Unseasonably wet (flooding)
  • Unseasonably long freeze (ground frozen)

Half hardy

These plants can survive mild winters and usually require shelter in southern parts of the UK, they usually require more robust protection methods in more northern areas.

Half hardy plants are usually poorly affected by cold wet conditions such as Mediterranean plants like Rosmarinus and Lavandula.

If the ground is wet and poorly drained it is likely they will be lost in anything more than an average winter.

There are also plants such as citrus that can handle to cold conditions as long as they are not wet. In this can all that you need to do is bring into a unheated conservatory and reduce watering. If you bring them inside over winter it is too hot and you will start to notice leaves dropping, they usually don’t recover until they are put back outside.

Lavandula Angustifolia

Tender plants

Tender plants are usually treated as annuals such as Petunia and bedding Geraniums, these plants usually dislike anything more than a mild frost.

Tender Plants that are to be kept year after year such as Canna, Dicksonia or Musa will require some type of protection. In some places in the UK even with protection there is a risk that a tender plant will be lost and one of the only ways to minimise this risk is to also bring them in to a frost-free greenhouse, conservatory or garage.

Plants in pots

When plants are in pots there is a higher risk of damage caused by freezing conditions, this risk is maximised when a pot has poor drainage leaving extra water in the pot to freeze. This extra water freezing in a pot is also a reason for most pots cracking.

The best way to overcome these risks is to first ensure that the drainage holes are not blocked by roots or excess soil and also raise the pot off the ground with pot feet.

Ideally you should also move a pot to a sheltered frost-free area next to a building if possible.

If you can’t move the pot then the pot can be wrapped in bubble wrap or fleece.

How to protect

There are many ways of protecting plants during the winter months, the following is a list of some of the most common methods.

Avoid high nitrogen feeds
New growth in winter is most at risk of damage from frost, avoid feeding plants with a high nitrogen feed after September, instead it is best to move to a high potash phosphorus mix such as a tomato feed. This strengthens roots as well as stiffens leaves which can help plants to withstand freezing conditions.
Plants that offer their own protection
Many plants that fall in between hardy and half hardy such as the more tender Salvia and Penstemons can protect themselves from all but the harshest weather is they are not pruned back fully, leave about 30-45cm of growth during the winter. Only prune back fully until when the risk of frost has past and there is sign of new spring growth. Gunnera also offer protection but this requires a little more effort.
Natural blankets
Natural blankets When pruning a Gunnera back in autumn/Winter upturn the leaves and place on top of the crown of the plant, this acts like a blanket to protect the plant during the winter and the new growth will push through in spring. Most perennials with the odd exception such as Paeonia also benefit from a thick layer of mulch or compost over them, this acts as a blanket keeping the worst of the cold off the crown. It also aids to add organic matter to the soil as well as feeding the plants in spring when they begin to grow.
Working with close friends
Some half hardy plants need just a little protection during the winter months, this can sometimes be achieved by planting fully hardy shrubs especially evergreens in the correct area. By planting evergreen shrubs which blocks the prevailing winds or removes excess moister you can help to give extra protection to the more tender plants. You may have to use a mixture off all these options to get the best results.
Needs some love
For the plants that are treated as tender there is more work to be done, this may involve wrapping or digging up and placing in a frost-free area or both. If you are planning on digging up a plant to store over winter then in some situations the plant can be kept in its pot making lifting easier, you can then re-pot every year or two. Make sure that your garden soil is well drained and the drainage holes in the pot are free.

The most recognisable plants that get wrapped and not brought in is the Dicksonia, these are hard to lift and, in most cases, will survive the winter with the right protection. It is recommended to add a good amount of straw into the crown at the top of the plant where the fronds emerge, this should be packed in and be at least a couple of handfuls. This stops excess water sitting in the crown and freezing.

If the center of the crown freezes, most likely it will die and without it no new fronds can grow.

It is also recommended if you are in an area that suffers from prolonged cold spells with frozen ground, to also wrap the trunk in multiple layers of horticultural fleece.

Plants such as Canna and Musa are unlikely to survive more then minimal frost so will need to be lifted into a pot and stored in a frost-free area, at this point the leaves should be removed to reduce moisture loss and the soil be kept on the dry side of moist.

If your area is not fully frost free then you should also wrap the pot and plant in fleece.


Plant list

Half hardy (A little protection needed)
Half-hardy Salvias
Deciduous ferns
Deciduous ferns
Tender (A lot of love and care) - Lift/bring in
Evergreen Agapanthus
Musa (+ Banana relatives)
Dahlia (In wet areas)
Eucomis (In wet areas)
Citrus (cool area)
Phormium (In wet soils)
Salvia (tender forms)