Horticultural

Black magic in your garden

In the second of an occasional series of Q&As, I've been talking to black plant expert Karen Platt, author of the book Black Magic and Purple Passion. You can find out more about black plants on Karen's website.

When did you first become fascinated by black plants?

It all started when I was young, the only plant I ever really noticed was the purple beech, Fagus sylvatica Atropurpurea Group, I was fascinated by those purple leaves. Then it lay dormant until about ten years ago when I saw the black mondo grass, Ophiopogon planiscapus Nigrescens and it was so dark, so near to black that it stopped me in my tracks. I just went off searching for another plant I could find that was dark leaved or near to black in flower. To date, I have found an amazing 2750. For me, it is linked in my mind to Mary Quant, the fashion designer, Op-Art and Jazz. I even named my book after Ella Fitzgerald's rendition of That Old Black Magic. I almost always dress in black.

My favourite black plant is Ophiopogon planiscapus nigrescens. What's yours?

It is my all-time favourite because it is so dark and it's an excellent year-round plant offering good-looking foliage, tiny mauve flowers and persistent black berries. My favourite family of dark plants is the Aroid family, in particular Arisaemas and my favourite flower is Viola Molly Sanderson, a truly sexy little number.

Black plants seem to be everywhere these days. Why do you think they've become so trendy?

I am mostly responsible for that. I have spent 10 years persuading everyone that these plants are just as worthy in the garden as any other colour and the message has finally got through. People do not always give me credit, but those in the industry know. I am the only person in the world who has done any in-depth research on this group of plants, brought them together under the heading of "black plants" and promoted them by speaking engagements and writing. I had the first black plant nursery in the world, which I have just re-launched in England where I live.

How should black plants be fitted into an existing garden colour scheme: does it work best with muted shades or is contrast the key?

I actually love black borders that simply rely on the varied tones of what are termed "black plants" consisting of anything from bronze through purple to black. However, I do use contrast in my garden too, so I have a black foliage border relieved only by the flamboyant colours of dark-leaved dahlia and bronze-leaved Canna flowers, and opposite this I have my chartreuse to golden foliage border with dark flowers such as black Iris, That Old Black Magic is a favourite and dark Hemerocallis such as Dominic. If you are in doubt, just add it bit by bit. I always ask people to think about it as dark green, then they can get over their inhibitions and see beyond the black hole.

What do you predict is the next big trend in black plants?

I think we shall see more people follow my lead and learn how to successfully use black on its own to create stunning dark borders. It is one-dimensional to always use black as solely a highlight, it has much more to offer.

Getting warmer

Dr Dave S Reay, author of new book Climate Change Begins at Home, has kindly agreed to be the first subject of a new, occasional series here on Horticultural: Q&As that look at a particular aspect of gardening. Here, he explains how climate change is likely to change our gardening habits.

Dave is a Research Fellow at Edinburgh University and describes himself as a keen gardener and compost nut". You can check out his site, Greenhouse Gas Online, for more information on climate change and its effects.

What will be the impacts of climate change to our gardens?

Well, there’s some good news and some bad news. The good news is that a warming climate will mean longer growing seasons for many of our plants and less frost damage in winter. In recent decades spring has been receding by between 2 and 6 days earlier each decade and Autumn has been pushed back by about 2 days a decade.

Could we one day be growing things all year?

Yes, in the South at least. By 2080 we could see a year-round growing season for some plants in the South of England. The flowering time for Primroses in East Anglia has already gone from early February during the 70s to mid-November now.

Will all the extra carbon dioxide help too?

Maybe. Some of our plants will lap it up, but then again so will the weeds.

Is this the bad news you mentioned?

I’m afraid extra weeding is just the start of it. Things that need a good period of chilling in the winter to form flower buds - things like blackcurrants, raspberries and apples - could see poor cropping as the winters warm up.

Even worse are the pests and diseases currently kept at bay by winter chills. As things warm up pests like aphids will be able to get to work on our plants ever earlier, while things like red spider mite will find that life outside our glasshouses is now rather nice.

Not more aphids!

I’m afraid so, and along with them come the many diseases they carry. This is a particularly worrying problem for Scottish gardeners and growers. In the past we had sufficiently hard winters to keep the aphids and their viruses in check long enough to produce disease-free seed potatoes and soft-fruit plants. With warmer winters we’re likely to lose this advantage.

Apart from getting warmer what else will happen?

It’s going to get a good deal wetter in winter and much drier in summer. Hotter, much drier summers will sound the death knell for lush green lawns in much of the south of England. Drier summers will also hit those plants that prefer cool moist conditions, like Primulas and ferns. Dry summers also mean yet more mildew problems – god knows we already have enough with the Honeysuckles in my garden!

Sounds like quite a lot of bad news for our plants?

 Yes, and for us gardeners too. The predictions from the Department of Health are that by 2050 malaria may have become re-established in England, that scorching summers will be leading to an extra 5,000 cases of skin cancer each year, and that the numbers suffering cataracts due to all that blazing sun will rise by an extra 2,000. It’s enough to make you want to retire to watch Gardeners’ World with the curtains shut and the air-conditioning turned up full blast.

Is there anything we can do about it? I know that driving a small car or fitting low energy bulbs can help fight climate change, but can we do anything in the garden?

Yes, plenty. Firstly, if you grow some of your own food then give yourself a pat on the back. The average family buying all their food from the supermarket will be responsible for more than 4 tonnes of greenhouse emissions each year due to all the transport involved in getting the food to their dining table (called food miles). The more produce you grow yourself the less food miles and so the less emissions.

What about composting, is that a good idea?

Composting is the last word in recycling and great for cutting emissions. The kitchen and garden waste from the average family leads to about a tonne of greenhouse emissions every year if it ends up rotting in a landfill site. By putting it through a wormery or composter you not only avoid these emissions but get piles of top-grade crumbly compost ("black gold") too.

With dying lawns in the south and new plants extending their ranges northwards it sounds as though our gardens will be looking rather different in years to come.

Yes, things will definitely change. How severe and rapid the changes actually are is largely down to us and the amounts of greenhouse gas we release. Our gardens can really punch above their weight in the fight against global warming. Let’s get out there and get them into shape.