How to plant a winter window box

December 1st, 2019
Posted In: Container gardening

The ideal winter window box is pretty but easy to look after. And preferably I’d like it to last through spring until it’s time to do the summer window boxes.

So I asked garden designer and GBBO finalist Jane Beedle (@janebbakes on Instagram) for her tips on creating an easy-care winter window box with maximum kerb appeal. You can find out how Jane transformed a muddy backyard into a beautiful contemporary garden (without busting the budget!) here. 

First we went along to a local plant nursery, Meadow Grange near Canterbury, to shop for the plants.

The window box planting formula: height, colour, trailing

All window boxes, not just winter ones, need three elements. They need some height and structure, a trailing element and, of course, colour.

‘I’ll start by looking for plants with some height and structure, said Jane. ‘Then I’ll add a trailing plant, and some colour.’

Shopping for plants at Meadow Grange

We went to Meadow Grange nursery in Blean, near Canterbury to choose from a wide range of shrubs and seasonal plants. Put your plants together in the trolley to see how they would work in the window box.

We started with the colour. Red, pink or white cyclamen are a good choice for Christmas. Jane spent a bit of time picking out fifteen red cyclamen plants which were close in shade to each other.

‘You need to pack a winter window box much more tightly than a summer one,’ said Jane. ‘In summer, the plants grow to fill the box quite quickly but they won’t grow in winter, so if anything you have to over-stuff it.’

The ‘three colour’ rule for successful window boxes

There’s a well known rule when choosing colours in window boxes. You should stick to three colours, and not to forget that green foliage is a colour. A window box is a limited space and it’s easy for it to look messy.

‘Although I think you can get away with combining a range of soft pinks, blues and purples in the summer,’ added Jane. So she decided on  red, rather pink or white cyclamen, not all three.

Jane added a variegated ivy as the trailing element. There are more choices of trailing greenery in summer, but in winter, it’s probably going to be ivy. She picked out some ivy pots that were already trailing – ‘they’re not going to grow much at this time of year, so pick out the ivy lengths you want.’

Winter box with cyclamen and grey foliage

There are three colours here – red (cyclamen), grey and green (both foliage).

However, you can split ivy plants. Just one or two plants can provide trailing stems all the way along the window box.

A window box needs structure

Next comes structure and we came up with three choices: some miniature golden cypresses, some very small eucalyptus and also some upright rosemary.

‘Try out the combinations at the nursery’, advises Jane.

We lined up the rosemary, with a small stripey grass and the cyclamen. Nice, but it wasn’t exactly what she wanted.

Although Jane liked the idea of using herbs because it meant that they would be used – it seems more sustainable.

Try different plants for height and structure

We tried out rosemary (now known officially as Salvia rosemarinus!) for the height and structure.

Next we lined up the golden cypress and red cyclamen with the ivy. This was vibrant. Perhaps too vibrant?

Miniature cypress trees for a window box

Golden cyprus plants for a zingy contrast in the winter window box?

So we substituted some small eucalyptus plants instead of the cypress. Their grey-green looked beautiful with the cyclamen.

Eucalyptus, cyclamen, ivy and barbed wire plant for a winter window box.

Final choice – a really pretty combination of eucalyptus, ivy, cyclamen, barbed wire plant and Leucothoe ‘Scarletta’, a shrub with red-tinted leaves.

Jane completed the plant choices by adding another silver-leafed plant, known as the Barbed Wire Plant to add texture and light.

Many evergreen plants make a good choice for winter window boxes. See 10 easy care evergreen pots for more suggestions.

Planting tips for container gardening in winter

Back home, Jane tipped half the compost out of her window boxes. ‘Because plants aren’t growing in the winter, you don’t need to replace all the compost,’ she said. ‘Unless, of course, you’ve got vine weevil, in which case you have to replace it all.’

Tips on planting a winter window box

Overplant a winter window box because the plants don’t grow in winter.

Before topping up with the new compost, she dotted some narcissi bulbs in. They’ll grow up in the spring – ‘just be careful to choose dwarf varieties,’ advised Jane. ‘You don’t want anything too tall.’

Then she topped up with soil and stuffed the window boxes as full of plants as she could manage. Although she’d bought masses of plants, there still weren’t quite enough when they’re packed tight. She’d been hoping to fill two pots in the front garden, too, but that will have to be for another day.

Even though you’re only using a small amount of compost, make sure it is peat-free. I’ve found Melcourt Sylvagrow compost excellent and it’s endorsed by the RHS.

Don’t water a window box until…

‘Don’t water window boxes until you’ve got them up on the window ledge,’ advised Jane. ‘Or they’ll be too heavy to lift.’

Water a winter window box when it's in situ

The final window boxes up on the sill. Water them once you’ve got them in place.

She hoisted them into place, tidied up a few stray scraps of soil, and watered them.

Make a winter window box last till May

‘The cyclamen probably won’t last much beyond early January,’ she said. ‘So I’ll take them out and add primulas or another early flowering spring flower. But the rest of the plants can stay there until I do my summer window boxes in May.’

In winter, plants don’t grow much. So you can take flowering plants out of a winter window box and replace them with spring flowers without disturbing the roots of the evergreen elements. This is one of the very useful tips in the Winter Pots post I also did with Jane.

Generally, a winter window box needs less maintenance than a summer one. All plants in pots get their food and water from you, not from the ground, but they don’t really grow much in winter, so you won’t have to water as often. And most people don’t fertilise their pots and window boxes in winter. They only need feeding when growth starts again in the spring. For more about keeping your containers looking good, see Your Best Garden Pots Ever. 

More container gardening tips

Arthur Parkinson’s The Flower Yard shows how you can have a vibrant flower garden, entirely grown in pots. And Alan Titchmarsh’s How to Garden: Container Gardening is a thorough and practical manual, covering everything you need to know to grow healthy, beautiful plants in pots.

I’m often asked for recommendations for gardening books, products and tools so I’ve put together some useful lists on the Middlesized Garden Amazon store, such as this Window Boxes & More list. I’ve picked out some window boxes from companies I’ve used, plus peat-free compost for planting window boxes. Note that links to Amazon are affiliate, see disclosure.

See the winter window boxes on video:

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4 comments on "How to plant a winter window box"

  1. Angie Snell says:

    Would eucalyptus be hardy enough in the north?

    1. Eucalyptus varies in how hardy it is, depending on variety, but generally, if it’s sold in the UK, it’s hardy enough for all UK winters. There should be more information on the label, too, and you could check with the plant nursery or garden centre.

  2. Bernadette O'Keeffe says:

    Tips for windowbox were helpful and inspiring. Many thanjs

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