Master Horticulturist Advises These 16 Plants For Winter Window Boxes
Elizabeth is a Permaculture Garden Designer, Sustainability Consultant and Professional Writer, working as an advocate for positive change. She graduated from the University of St. Andrews with an MA in English and Philosophy and obtained a Diploma in Applied Permaculture Design from the Permaculture Association.
Reviewed By PETER LICKORISH
Peter is a Horticulture Lecturer and self-employed Horticulturist, with a passion for diverse areas of the industry - from garden design to the science behind plant growth and propagation. He has completed the Royal Horticultural Society’s Master of Horticulture (MHort) Award and lectures on RHS courses at Bedford College.
Window boxes can brighten up your life – not just in summer but also during the winter months.
But choosing the right plants to grow in winter window boxes is key.
It is important to think about the size of a particular window box, and where exactly it is positioned.
A window box in a sunnier spot will be suitable for certain plants, while one in a more shaded position will be suitable for others.
With the right plant choices, you can enjoy attractive displays all through the coldest months.
And you may even be able to continue growing edibles in a window box all winter long.
To help you find the right plant combinations for your winter window boxes, here are our top suggestions for plants that you should grow:
Growing Edibles
As a sustainable gardener, growing at least some of your own food is always a great thing to do.
You do not have to choose between edible, useful plants and aesthetics either.
Many edible plants which can survive outdoors over winter across much of the UK in a sunny and relatively sheltered spot can also be attractive ornamentals.
Brassicas
Some of my top picks for a winter window box are in the Brassica (cabbage) family.
There are a number of kales, cabbages and Asian greens which can survive cold temperatures and provide you with a source of food throughout the winter months.
Kales and cabbages can be beautiful too – with their different types of foliage in greens, and also deep purple hues.
The kale ‘Dwarf Blue Scotch’ is an especially compact variety with an elegant blue hue to its curly leaves.
Alliums
You can also consider adding some alliums (overwintering onions, or perennial onions, for example to your window box, to provide food the following year.
“Consider planting the red onion ‘Electric’ as sets in mid-autumn,” shares Peter Lickorish, a Master Horticulturist.
Beans / Peas
Overwintering broad beans or peas could also be an option in some window boxes in some areas.
“‘The Sutton’ is among the smaller broad bean varieties, but consider replacing your window box with a spring bulb display to let this plant reach its full height of 45cm somewhere away from the window,” says Peter.
And with a little protection, a range of other leafy crops, root crops and micro-greens could be grown.
Herbs
Though you will likely leave them unharvested during the winter months, many evergreen herbs can also be good choices for a winter window box.
Rosemary, thyme etc. can often overwinter successfully in a window box in the right spot – and many should remain green throughout the winter months.
Pansies
Pansies and violas are common winter bedding plants, but you might not realise that these are also edible flowers, which can be added to a winter salad.
However, buying in bedding plants is not usually the most eco-friendly choice.
With hugely detrimental peat compost, and plastic plugs or pots, bedding plants are generally best avoided if you are trying to garden in a sustainable and eco-friendly way.
Instead, consider sowing these plants from seed yourself at home.
Plan ahead for winter in late spring and early summer to make sure you limit your negative impact on people and planet.
Dwarf Conifers
If you would rather not go to the trouble of growing edibles year-round, and simply want a long-lasting and attractive winter display, conifers can be a low-maintenance choice.
Junipers, for example, with dwarf or prostrate forms can be ideal choices for winter window boxes.
There are a number of conifers with small and restricted forms which can look beautiful in a window box over the winter months.
“One of my favourite low-growing junipers is Juniperus horizontalis ‘Blue Chip’,” shares Peter.
“The clue is in the name because it will hug the ground or a window box!”
Small Evergreen Shrubs
There are also plenty of small evergreen shrubs and sub-shrubs that can look wonderful in winter window boxes, providing plenty of visual interest and appeal over the coldest months.
Gaultheria procumbens, for example, is one option to consider.
Plant a small potted plant of this species into a window box, and when winter is done, it might even be suitable to replant and grow elsewhere in your garden.
Skimmia japonica and Skimmia japonica subsp. reevesiana are other interesting small shrubs to consider.
Again, there are examples that are rather diminutive in size, and which will provide winter interest in a window box before – potentially – being planted out elsewhere.
Many Daphnes are also ideal for window boxes, some providing blooms in the winter months.
For colour and interest over the winter months, Daphnes can be hard to beat.
They are slow growing, but will eventually out-grow their window box and can be planted out in the garden.
There are also plenty of other small evergreen shrubs and subshrubs to consider growing in a window box over the winter months.
But the above are all great choices to maximise interest and visual appeal over the coldest part of the year.
Ivy
While some Hedera (ivy) is extremely vigorous, and will quickly take over, many ivy varieties are perfect for winter window boxes.
These spill down over the front of a window box, creating a beautiful effect.
Ivy trailing from a window box can give a sense of abundance and lushness and it can look good alongside a wide range of other plants.
Heathers
Winter flowering heathers such as Erica carnea and Erica x darleyensis are also top picks for a winter window box.
They can look good alongside some herb shrubs like rosemary etc, or alongside a range of evergreen alpine plants.
There are numerous evergreen alpines that can look wonderful throughout the year, and which can thrive in a well-drained window box in the right spot.
Other Winter Flowering Perennials
Helleborus x hybridus (Hybrid Hellebores) and Helleborus niger (The Christmas Rose) are great choices for a winter window box, blooming as they do during the coldest months.
Cyclamen coum is a perennial bulb that you could also consider growing in winter window boxes for some of the earliest blooms of the year.
Evergreen Ferns In A Shady Spot
In a shady spot, you may find it more difficult to find plants that will thrive in a winter window box.
But some of the plants above – such as conifers and ivy, should still do fine.
And you can also consider adding a range of interesting evergreen ferns.
Creating a small window box fernery can provide a lot more interest than you might think.
There are ferns that come in a wide range of foliage types, forms and shades.
The fern Asplenium trichomanes is among the smaller evergreen ferns, with charismatic bright green fronds.
Snowdrops, and other late-winter/early spring bulbs could also be considered for a window box in a shaded location.
Iris reticulata are tiny irises, best viewed close up, such as in a window box.
