How does your garden grow: Pia Östlund of the Chelsea Physic Garden, London

I grew up on the west coast of Sweden. In Scandinavia, people see the whole of nature as their extended garden. Foraging for berries and mushrooms, fishing and wild swimming are part of daily life.

When I moved to London to study graphic design at Central St Martins, I missed all that. After college, I won a competition to design a garden that demonstrated geological history. With only a small space, I had to engage people’s imagination. I was inspired by William Blake’s line, “To see a world in a grain of sand”. One of the judges was Rosie Atkins, who was then curator of the Chelsea Physic Garden.

I came here 14 years ago, and I still work at least one day a week as a freelance design consultant for the garden. I don’t have a garden at home, but I think of the Chelsea Physic Garden, along with Hackney Marshes, Colombia Road Flower Market and Hampstead Heath, as my extended garden. My role is all about representing the reality of this historic place in interpretive signage, guidance material and merchandising. I have to epitomise what is out there in images.

The garden has given something back to me. One day Rosie showed me an 1855 volume, Ferns Of Great Britain & Ireland, by Thomas Moore, the Victorian curator responsible for our Cool Fernery area. The curious, lifelike – as well as life-size – representations of ferns looked like nothing I had seen before. They were too detailed to be drawn by hand, yet clearly not photographs. Even stranger was the texture of the plants, which could be felt by running one’s finger across the image. Despite having quite a lot of experience of different types of printing, I was at a loss. The only clue was a small caption in the corner of the page that read “Nature Printing”. During the 19th century, there was a hunger for a form of scientific image-making, free from the artist’s hand. A plant was pressed into a sheet of lead under high pressure. This highly detailed impression was copied on to a copper printing plate and used for the mass printing of botanical works. I am close to reviving the method and hope to have an exhibition before long.
My favourite spot

I love the Atlantic Islands greenhouse with its 1930s structure and cast-iron and slate shelving. The plants are strange. They cast beautiful shadows and are totally unsuitable for nature printing, so I can appreciate them without thinking what I can make from them.

Gardens: what to do this week

Chop this

If you have a buddleia threatening to take over your garden, now is the time for action. Be stout of heart; this is a rugged plant that will regenerate quickly, so prune it back to just above ground level, leaving two or three buds on each stem for regrowth to start.

Discover this

Across the Thames from Tate Britain lies the Garden Museum; this exhibition space, garden and place to learn is a retreat from the capital’s hustle and bustle. On 10 March, join no-dig gardening guru Charles Dowding to find out how to grow more veg with less backache; on 17 March florist and grower Georgie Newbery reveals her secrets of the cutting garden.

Plant this

If you’re looking for unabashed glamour and colour this summer, begonias are the ultimate annuals for sunny spots. Truffle begonia ‘Peach’ and ‘Cream’ trail to 30cm and look great in patio containers or hanging baskets. Buy the begonia Truffles collection of 10 plug plants for £17.98, or 20 for £24.96 (including UK mainland p&p). To order, call 0330 333 6856, quoting ref GU296, or go to our readers’ offers page. Dispatch next month.

Office plants can make workers 15% more productive, says study

The office pot plant has often been criticised as a symbol of corporate or government waste. Taxpayer, ratepayer and shareholder-funded foliage has regularly been stripped from offices by efficiency or cost-cutting crusaders.
But that might be short-term thinking, as leafy-green offices enriched with plants can boost productivity by 15%, according to Alex Haslam of University of Queensland’s School of Psychology.
An international study assesses the long-term impacts of plants in an office environment and the findings challenge the belief that money spent on plants is money wasted.
Prof Haslam, a co-author, said the research team examined the impact of “lean” versus “green” office space on employees from two large commercial offices in the UK and the Netherlands.
Their results challenge modern business philosophies that suggest a lean office is a more productive one, Haslam said.
“Modern offices and desks have been stripped back to create sparse spaces – our findings question this widespread theory that less is more – sometimes less is just less,” he said.
He said that investing in office landscaping may pay off through an increase in office workers’ quality of life and productivity.
“Lean, it appears, is meaner than green, not only because it is less pleasant but also because it is less productive,” concludes the study, published in the Journal of Experimental Psychology: Applied.

Garden planning: how to plant combinations of flowers

Singing the blues: the inky flowers of Ceratostigma willmottianum. Photograph: Alamy
It is a wonderful interlude when the season tips from summer into autumn, leaving behind the need to keep everything prim and proper. A well-planned garden will have plenty that is now at its best, for a host of plants have spent the summer preparing for just this moment: aster, black-eyed Susan and Joe-Pye weed soar head and shoulders above us, with rioting nasturtiums ascending where they have got away and autumn crocuses breaking their summer dormancy.
The term "well-planned" might engender fear, gloom or indeed a smile, but good planning is no different from putting together a meal. You need complementary ingredients, with contrasts and a sequence of events from start to finish. Pacing a planting is the greater part of understanding how to combine plants, and though I might initially think about a mood or a colour scheme when I am planning, it is ensuring that there is continuing seasonal interest that ultimately makes a planting scheme earn its keep.
Right now we are spoilt for choice, with a palette of autumn-fruiting shrubs and trees waiting to colour up. Hip-bearing roses and euonymus, rowans, hawthorns and ink-berried elders are a fine backdrop and will provide some structure. Underneath their limbs you might plant spring bulbs and early summer perennials, but out in the open you need to leave yourself room for a range of perennials to cover the several months of the growing season.
Think about how plants appear in a meadow: cowslips first, buttercups rising above them, moon daisies next with the ascending grasses and finally wild carrots, scabious and knapweeds – one covering for the next. Planning a perennial planting benefits from much the same approach: aim to create a knit of companions so that in any one space you might find plants for at least three seasons.
Many late-flowering perennials are lofty and will sail above their neighbours to cover for them once they are finished. You need to leave them enough room to build up strength over the summer, and pairing them with perennials that come up early but are happy to sink into their shade once the others ascend will see you through the summer. Take, for instance, a combination of early geraniums and peonies, interplanted with asters to rise above them after they are over and you're halfway there. Add bulbs for spring and a sprinkling of annual "Fairy Wings" poppies to seek out the gaps.
To ensure that you have good cover for this late in the season, you should reserve up to a third of your space for late perennials and their allies. It might seem like space taken from the summer garden, but the wait will be worth it. A hot spot among early nepeta and stachys might give rise to late-flowering Ceratostigma willmottianum, with its inky-blue flowers and red in the foliage. Add some Amaryllis belladonna in a really warm spot and you will gain the company of "Naked Ladies" that rise up out of nowhere.
Rudbeckias are not backward in coming forward and will wash the late summer garden with colour. I use mid-sized Rudbeckia fulgida deamii, with dark cones that last well into winter, the delicate R subtomentosa and R laciniata "Herbstsonne". I love this rangy plant where there is room – and you will need it, as it towers above head height. To soften the blow of the rudbeckias, team them with late-flowering grasses to throw a bronzed veil over the daisies. Molinia caerulea "Windspiel", Panicum strictum or Miscanthus nepalensis will take this long to look their best but will be worth the wait. They will have remained smart the summer long, waiting for their fast and furious early companions to come and go.
You will forget the bulbs that lie in wait at their feet ready to reappear in six months' time, and the perfume of the Valeriana officinalis that made its home among their stems in early summer, and be happy that you planned for the finale.
Get growing
Simple combinations make the best ones. Choose two or three plants that like the same conditions and you are more than half way to striking the right balance.

How to grow chillies

Indian style: Apache chillies are great for windowsills. Photograph: Jo Whitworth/Gap Photos
In a hellishly hot polytunnel in Bedfordshire, grower Joanna Plumb is laying to rest the myth that chillies are hard to grow. In fact, it pays to be a bit lax: "If you let them wilt and stress the plant out," she says. "It's one way of getting hotter chillies because the plant thinks it's going to die and puts all its energy into reproducing."
Plumb is an expert chilli grower and owner of Edible Ornamentals, growing thousands of chillies every year for everyone from supermarkets to Fortnum & Mason. She's convinced that these hot fruits are a great crop for the style of growing most of us can manage in modern life: chillies are perfectly content in a pot on a sunny windowsill or patio, with fruits that can be picked over a long period and easily stored for the following year.
It's too late to grow chillies from seed this year, but now's the perfect time to buy a couple of plants: if you pick the right variety, you should be harvesting until Christmas. The best ones for growing on windowsills and patios are compact and bushy, such as Apache and Prairie Fire: some of the bigger chillies can grow up to 2m. There are a few simple rules: put them in full sun, water little and often, and remember to feed. If you already have tomato feed, you can use it on chillies, though there is also a specially formulated feed called Chilli Focus. When roots start to show through the base of the container, switch the plant to a bigger pot using multipurpose compost.
Plumb says the most common moan from indoor growers is that their plants have dropped their flowers, but no fruits follow. There's an easy solution to this wrinkle, caused by the lack of insects for pollination: use a small paintbrush gently to rub the insides of the flowers and move pollen from bloom to bloom, mimicking an insect at work. If you have some outside space, the alternative is to give them some fresh air, but it's best to opt for pots rather than planting chillies in the ground. They need a minimum night-time temperature of 7C, so bring them inside in September and they should continue to fruit until December. You may even find you can enjoy a second harvest the following summer. Time outdoors also helps to defeat the chilli plant's main foe, the aphid: ladybirds will soon handle this pest if given the chance. Otherwise, keep a close eye on your indoor plants and gently rub off any aphid invaders with the tips of your fingers.
Hot harvest
Chillies will be ready to snip off from next month onwards, but there's no need to hang on until all the fruits are bright red. Harvest some while they are green and you'll encourage the plant to keep fruiting. While the UK is fixated with red chillies, in most countries chillies are picked when green. "A chilli when full size and green has maximum heat," Plumb say. "When it goes red, it is as hot, but it goes sweeter, like the difference between a green and a red sweet pepper."
Don't worry if your chillies turn black – this is simply part of the ripening process and the fruits will turn red in a few days. If you end up with more chillies than you can eat, freeze them whole, or purée them and freeze in an ice-cube tray; the thinner-walled varieties, such as Anaheim, are excellent dried – pick perfect fruits and use a darning needle to pierce the thick, green stem with fishing wire or strong thread and string them together. Hang them up in a sunny, airy spot (in front of a south-facing window, say). That way, you'll still be eating chillies when next summer's crop is about to ripen.