Window box plants

by Rhiannon James

A window box from below (credit: Sarah Richter)

Whether you have space outdoors or not, the one garden you can almost always enjoy is a window box. Outside, window boxes will transform the look of your house and welcome you home every evening with a fanfare of flowers. Inside, they can create a herb garden in your kitchen or a jungle in your hall. Our experts share their favourite window box combinations.

Erysimum 'Bowles's Mauve'

Erysimum ‘Bowles’s Mauve’ (credit: Josh S Jackson)

“Window boxes are perfect for framing your view of the outside world and beautify your property to boot. Evergreens such as Buxus sempervirens (box) work well for year-round greenery and can cope with low levels of watering and maintenance. For something more colourful, it’s worth slotting in bedding plants in late spring and autumn. For year-round colour, a different palette of plants is called for. Try Nemesia denticulata ‘Confetti’ for virtually 365 days of flowering and a gentle lax slightly wild habit. For more upright endless colour Erysimum ‘Bowles’s Mauve’ is just the ticket. It has beautiful pale violet flowers which are sustained year-round and can cope with low levels of water.”

Nick Bailey, Head Gardener at The Chelsea Physic Garden

mint, rosemary and sage

Mint, rosemary and sage (credit: mint and sage, Alice Henneman, rosemary, Austin Keys

“My favourite window boxes often contain herbs – this works particularly well for windowsills in kitchens, creating a beautiful and fragrant miniature garden that can be incorporated into cooking.  I also use them for bathroom window boxes – herbs are wonderfully aromatic additions to any bathroom routine.  I would recommend rosemary, lemon thyme, marjoram and sage.  Mint is beautiful too, though this needs to be contained in its own pot as it’s a bit of a thug and will take over!

I love the fact that herbs flower too. For me, seeing the delicate lavender-coloured flowers appearing on rosemary, heralds the beginning of spring. Herb foliage is always so interesting and sensual, it’s the taste and flavour of summer and it takes me straight to the Greek Islands or Tuscany.

For indoor window box schemes, you can’t go wrong with succulents – they are so beautiful and interesting and very fashionable right now.  You can’t neglect them completely, but they are low maintenance and the ideal choice for those with less than green fingers.  Vary the colours and create a beautiful mini landscape with different shapes, sizes and textures.”

Ian Drummond, Creative Director at Indoor Garden Design

Erigeron and Pelargonium 'Fragrans'

Erigeron karvinskianus (credit: M. Martin Vicente) and Pelargonium ‘Fragrans’ (credit: Forest and Kim Starr)

“My favourite plant to put in window boxes, has to be Erigeron karvinskianus, a small delicate plant, which provides mounds of frothy white daisy-like flowers. It is often found growing from walls in coastal areas, but makes the most fantastic container plant – flowering from May, until the first frosts. If left in the container in a sheltered spot, they will over winter until the following year, but may require a little haircut.  I have a window box outside my kitchen window, which I always plant up with ferns, scented Pelargonium ‘Fragrans’ and masses of Erigeron. The combination of white and green is always a winner, but also this combination of plants does not require too much attention, other than regular watering and deadheading occasionally.”

Thomas Broom, Horticultural Manager at Petersham Nurseries

allium and verbena

Allium sphaerocephalon (credit: Bambo), Stipa tenuissima (credit: Paul Morris) and Verbena bonariensis ‘Lollipop’ (credit Southwell Garden Centre)

“To create the look of my Locanda Locatelli planting in a smaller window box I would suggest: Stipa tenuissima; Verbena bonariensis ‘Lollipop’; Allium sphaerocephalon which comes out quite late; and Allium cristophii for earlier in the summer and maybe Erigeron karvinskianus or Gypsophila repens ‘Rosenschleier’ to trail over the edge. I think that would probably be enough – too much in a smaller window box will just look a mess,”

For winter, you could use ferns, hellebores – ‘Wester Flisk’ is really good because it has nice texture – and bergenias – once they establish they’ll start to trail. In Italy you see bergenias tumbling down from window boxes, the roots get longer and they fall over the edge. Libertia is a lovely evergreen grassy plant which we tend to use in the winter even though it flowers in May. We also use some very late asters such as A. divaricatus and A. ageratoides ‘Starshine’ that are just going over – we just catch them before they fade.”

Declan Buckley, garden designer, Buckley Design Associates

lettuce Pam Corey

lettuce (credit: Pam Corey)

The Impatient Salad Box

This is one for the itchy-fingered. Plant up this window box and you will have platefuls of delicious, crunchy salad within a month – the nearest it gets to fast food in the gardening world! Buying supermarket salad could be seen as a bit of a cheat, but it is cheap and convenient and, if you separate the individual plants and plant them, you can end up with masses of mature lettuces for a quid. Pea and sunflower shoots are deliciously fresh-tasting and give the leaves a bit of crunch. Buying the dried peas and sunflower seeds from health food shops or grocers rather than garden centres is also very cost-effective since you get them in much larger quantities – perfect for a constant supply over the summer.

You will need

1 window box with drainage holes about 60cm long

Multipurpose, peat-free compost

1 tray of ‘living salad’ from the supermarket

Pea seeds (or dried peas from a grocer)

Sunflower seeds (you can get these from health food shops)

Alex Mitchell, author of Gardening on a Shoestring: 100 ways to create a garden on a budget which is packed with money-saving tips for gardeners

thyme and viola

Viola (credit: Steve Cavrich) and thyme (credit: Alice Henneman)

“I love having a mix of edibles in my window box, it gives a really natural feel and even when you’re not going to use them, they look fantastic and give off a wonderful smell. Rosemary and thyme are favourites of mine mixed with flowers such as pansies or violets to give that delicate colour and also tie into the edible theme.”

Isabelle Palmer, garden writer and owner of The Balcony Gardener

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