The Delights of Dahlias

After languishing for a while outside garden fashion, dahlias are suddenly being recognised again for their very many useful attributes. Long in flower (June to early December in a sheltered spot), easy to grow, invaluable in the summer border, a desirable cut flower — the list goes on! They offer a wide range of flower types, some small enough for terrace containers, as well as a rainbow of warm, vibrant colours. The dahlia’s return to popularity is long-overdue and much deserved!

Officially, the dahlia is a tender tuberous-rooted perennial, growing from scratch each year from chubby, finger-like roots. In colder areas these roots are lifted in the autumn to protect from frosts, the plants then started out again in the spring when the danger of frost has passed. However on the Isle of Wight, where I garden, they can be regarded as generally winter hardy with a little root protection against any unusually penetrating frosts.

Dahlias tolerate a wide range of soil types, but will do best in well-prepared, fertile soil, with good drainage, and positioned in full light. For super results, it is worth incorporating some well rotted manure into the soil, plus a handful of slow release organic fertiliser containing trace elements. Once the flowers start to appear, a high potash feed (I use tomato fertiliser) is very beneficial, given every couple of weeks through to early September.

Playing safe with dahlias for the winter involves lifting them when the first light frost has taken the foliage down; this is also the best procedure if more of that variety are required for the following year, as they can be split in the spring as growth starts from the tuber, to create further plants. After digging the tubers, trim the stems back to 6 – 8in, remove excess soil and allow any surface moisture to dry before transferring them to boxes containing old potting compost, moist sand or vermiculite. These boxes can then be overwintered in a frost free place, covered with an old blanket or fleece for extra protection until the spring when the growing cycle starts again. It is wise to check the tubers from time to time while in storage to make sure that none are rotting, or drying out.

In early spring simply split the tubers ensuring each piece has at least a couple of good initial shoots, pot up in general purpose compost and grow on in a frost free greenhouse. It is important to give minimal water until growth starts in earnest. For sturdy plants, five shoots are the maximum to allow to grow from each tuber, any excess should be pinched out; the main shoot produced from these five will also benefit from the tip being removed after planting out, just as the first flower buds are formed.

If nowhere under cover is available to grow on dahlias that are being split to propagate, then they can simply be planted out in late May in their final positions, each split piece possessing shoots and root — although involving less work, these plants will start to flower several weeks behind those brought on in a greenhouse.

The larger varieties will need some support to prevent any gusty summer winds damaging the sappy hollow stems when the plant is heavy with flower. This support can either be a short stake plus some twine, or make, as I do, a wire cylinder of stock fencing held onto a metal upright by cable ties. These last well from year to year, and can also be used to enclose a little root protection compost in colder gardens to benefit plants being overwintered in the ground.

Besides supporting the plants, other routine care involves deadheading. Having a regular round of deadheading keeps the plant smart and encourages a very long season of bloom. Unfortunately dahlias are beloved of slugs, so to avoid any disappointment they should be protected with organic slug pellets, nematodes, or a physical barrier right from the outset.

The main reason dahlias were banished to the horticultural wilderness for so long was the perception that their flowers could be coarse and their colours unsubtle. However recent breeding has brought forth delicate cultivars, intriguing new types, and a much more attractive palette — there are now dahlias for every scheme and every garden style. I particularly value the very dark shades through from deepest midnight purple to velvety chocolate brown; these lusciously deep tones are a wonderful contrast to the reds, vermillion and apricot shades of the cannas they share space with in my borders.

Potting up an overwintered tuber in spring

Planting out after growing on in the greenhouse

Placing the wire support that will be quickly covered by the growing plant

Using the wire support to enclose compost for protection of a dahlia left in the ground over winter

Some Favourite Varieties:

‘Ice and Fire’

Dahlia ‘Lubega Power Yellow-Orange’

Dahlia ‘Yellow Star


Dahlia ‘Lubega Power Tricolor’





Yacon — A Newcomer from South America

All the way from South America, rather like Paddington Bear, comes my new favourite vegetable, Yacon, Smallanthus sonchifolius, distantly related to Jerusalem artichokes and carrying with it a host of intriguing culinary possibilities.

What is it?

Yacon tubers form underground beneath a robust, leafy plant, slightly reminiscent when dug of large baking potatoes, but that is where the similarity ends.  Yacon, meaning ‘water root’ in the Inca language, has flesh that is juicy, slightly sweet and yielding, with a flavour reminiscent of pears, or melons, with a hint of celery.  In fact in its home country, this beguiling tuber is used in fruit salads as well as vegetable dishes.

A most exciting feature of Yacon is the super sweet syrup that can be extracted from it, containing an indigestible sugar, inulin.  In effect the delicious toffee-tasting syrup is virtually calorie free, does not raise blood sugar, and so both tubers and sweet syrup are suitable for diabetics.  The inulin in yacon syrup also has great benefits for the bacteria in the gut where it is said to aid digestion and boost the immune system.  These health benefits have lead to yacon becoming a major crop, especially in the US where most of the syrup extraction takes place.

Growing Yacon

Yacon is a tender perennial plant, therefore with a little TLC, once you have your first plant, it should be with you forever; in fact its cultivation and care are very much like dahlias, so if you grow dahlias, yacon will be a cinch!  It is rarely troubled by any pests or diseases, easy and willing to grow, but does however need a long growing season, the tubers bulking up in the late autumn, to be dug in mild years just before Christmas, in advance of any penetrating ground frost.

To start off, either buy rooted cuttings in the spring or get a division from someone already growing yacon.  I usually treat my stored crowns like dahlias, starting them off in the greenhouse until shoots appear.  At that point I divide into individual plants and pot up, before growing them on for planting out in May in a sheltered sunny spot, when all danger of frost has passed.

Yacon does appreciate a rich, fertile growing medium with plenty of well rotted manure and compost, deeply incorporated into the soil.  Cultivating the soil to a good depth before planting greatly helps the process of lifting the crop in the autumn, otherwise the main tubers can break off and stubbornly remain in the ground.

Once planted out, a lush and leafy plant will quickly develop to a height of up to 2 metres, with small orange yellow flowers in the late summer.  If things are going to plan, the burgeoning tubers will start to raise the soil circling the crown of the plant around September / October time

Harvesting and Storing Yacon

Leaving harvesting as late as possible will give the most cropping potential.  When the moment arrives, usually when the top growth has been blackened off by the first air frost, cut back the remaining stems to about 10 cm and dig up the crown consisting of the bulky storage tubers (the crop), plus small propagation roots, or ‘buds’ growing just under the surface.  The crowns for next year’s plants are stored much like dahlias for the winter in a cool but frost-free place where they won’t dry out.




The big tubers, carefully snapped from the crown, are crunchy, sweet and refreshing immediately — after washing and peeling can be eaten just like a carrot — but they do have the potential to become sweeter if left out in the sun for a few days.  Only undamaged tubers can be stored for several months in paper or hessian sacks, much like potatoes, in a frost-free garage or shed.  Any damaged tubers should be used immediately or made into syrup.




Yacon in the Kitchen

Crunchy yacon is a delicious and different addition to savoury salads — try substituting the apple in Waldrof salad with diced yacon, or combine grated carrots, yacon ‘sticks’ and sliced celery with a grain mustard vinaigrette — in fact it absorbs dressings and sauces of all kinds very readily, making it a tasty vehicle for other flavours. In the Peruvian tradition of ‘salpicon’ (fruit salad), versatile yacon can also make a delightful fruit dessert when chopped and added to your choice of pineapple, melon, papaya or mango, dressed with fresh orange juice. If used raw, the flesh of yacon will discolour, much like an apple, so after peeling and preparing, sprinkle immediately with a little dilute lemon juice, or dressing, to preserve its attractive white colour.  Alternatively, for a hot dish, yacon can be roasted with other root vegetables tossed with olive oil, balsamic vinegar and herbs, or even just simply steamed.

Sweet Treat

Once you have grown enough yacon to have some spare you can think about extracting the sweet liquid using a food processor — about 12 kgs makes a litre of the precious syrup.  Simply wash and peel the tubers in batches then whizz them up thoroughly; place in a large pan and simmer down gently at about 103 C until a delicious dark brown syrup is formed.  This sweet liquid is wonderful on porridge, or has a great affinity with cocoa when making ‘guilt-free’ chocolate treats!


Getting more from your garden!

Getting more from your garden!

By ‘getting more’ I mean multiplying up your favourite plants the cheap and easy way — by taking cuttings. Although September is thought to be late for taking cuttings, it is in fact my chosen moment. The busy spring and summer seasons of the gardening year are behind us, but light levels and warmth are still adequate to persuade the many half-hardies currently doing colourful duty in mixed borders and pots, to root in double quick time. By ‘half-hardies’ I mean the more tender perennials such as the larger Verbenas, Venidio-arctotis, Diascias, Salvias, some Osteospermum, and many of the foliage plants that are downright tender, including Iresine, Helchrysum petiolatum and Plectranthus argentatus. Interestingly I also routinely take Penstemon cuttings at this time of year, although they are hardy in the ground, I often treat them as annuals. In my garden, they flower their socks off in their first year for many weeks longer than older stock can ever manage.

I think it was the late, great gardener Christopher Lloyd who said that the process of taking cuttings is a ‘race between rotting and rooting’. Fortunately, with a little care, plants are much more willing to do the latter than the former!

Soft cuttings are taken from the ends of non-flowering stems, about three inches is what you need, and these chosen shoots should be strong, healthy and typical of the parent plant. While gathering cuttings from the garden, pop them in a polythene bag to prevent them wilting before you finish the job. I always trim my cuttings on a clean board, with a new scalpel blade that I sterilise between each batch. Working quickly, carefully trim off the lower leaves flush with the stem, and if you have a large number to do, mist them lightly during the process to prevent loss of moisture.

Getting More from Your Garden!

Trimming cuttings of Verbena ‘Homestead Purple’

When all of a batch are trimmed and ready, I dip the cut ends in hormone rooting gel. Most cuttings will root perfectly well without this extra help, but I find rooting gel does accelerate the process.

Getting More from Your Garden!

Dipping the cut ends in hormone rooting gel

As I have so many cuttings to do for my work, and for my own garden — around a thousand at this time of year — I use a rather high-tech rooting medium to speed things along. I find that pre-formed cubes made of biodegradable material, complete with a hole in the top for the cutting, are invaluable; not only do I get almost 100% success rate with these, but the plants seem to root more strongly, and most do so within 21 days. However, these little rooting cubes are by no means essential, most gardeners have good results by inserting the cuttings in damp potting compost just inside the perimeter of a three or four inch pot.

Getting More from Your Garden!

Inserting the prepared cuttings into the rooting cubes

Until roots have formed the cuttings need as much light as possible without ever being allowed to wilt or scorch. The way to do this if using a pot for the cuttings is to enclose them with a plastic bag held secure with a rubber band. A little refinement is to form a loop of wire, with the ends inserted in the pot, to hold the plastic bag clear of the leaves. I find that plastic in actual contact with the cuttings can lead to the dreaded rotting rather than rooting. During very hot bright days you may need to shade the pots to prevent overheating.

I am lucky enough to have a misting unit for my cuttings that works automatically with the aid of a ‘magic leaf’, a little gadget that senses when the cuttings are dry and initiates a burst of mist to keep them plump and perky until they root. You will usually know when rooting has taken place because the tip of the cuttings will start to grow away. If strongly rooted before the end of October, I pot them up individually in small pots and keep them just frost free, and on the dry side, in the greenhouse for the winter. A conservatory window cill would also be a fine location if you have only a few to overwinter. Those cuttings that have not rooted fully by the end of October, I simply leave undisturbed through the winter until the warming, lengthening days of spring encourage them into vigorous growth.

Getting More from Your Garden!

Some I prepared earlier — rooted in 14 days!

Although these tender perennials make great additions to borders — just as I use them in my garden to provide infill between the cannas, dahlias and ‘hardy exotics’ that form the backbone of my schemes — they are equally at home in more bijou gardens. They are happy in pots and containers where space is tight, and are joyously rewarding over a long summer season.

Groups from my own garden showing how tender perennials can lift mixed borders to another level, keeping them fresh and vibrant from late spring until the first frosts take them down.

Getting More from Your Garden!

Foreground, Venidio-arctotis daisies, raised from cuttings, with behind Dahlia ‘Bishop of Llandaff’, and seed sown Ricinus above


Getting More from Your Garden!

Foreground, spilling over the path is Verbena ‘Homestead Purple’, mingling with the tall pink Diascia personata, both from overwintered cuttings.


Getting More from Your Garden!

Foreground, Iresine and variegated Plectranthus argentatus, both tender and grown from cuttings. Background, Canna ‘Shenandoah’, and Ricinus ‘Impala’

Rock Dust

Rock Dust

I remember vividly seeing on television the literally earth-shattering images of the Mount St. Helens volcano erupting in the United States in 1980.  This gigantic explosion caused the collapse of a large portion of the mountain together with the ejection of millions of tons of volcanic dust which settled over eleven US states.  In the immediate vicinity a wasteland was created with the land buried in a massively destructive deep layer of ash, however in further outlying agricultural areas, some remarkable effects were reported from a lighter deposit of the rock dust.  Farmers noted a huge increase in yields — even to the extent that abandoned and unproductive orchards suddenly started producing viable crops again.

What had happened as a result of the eruption was nothing short of a natural ‘re-mineralisation’ of the land.  For thousands of years peoples have settled on the slopes of volcanoes (sometime with disastrous results, as in Pompeii) due to the exceptionally fertile and productive soil, rich with minerals and trace elements.  Glaciers are another natural method by which soil was created and made fertile. During the last ice age the crushing action of ice on volcanic rocks ground away the strata to produce many deep rich soils, that still feed human populations today, 10,000 years later.

For those of us who grow substantial amounts of our own food, keeping the soil replete with macro and micro-nutrients (or trace elements) is an important way of making sure that we also ‘mineralise’ ourselves for health and well-being.  A tiny but very significant percentage of vegetable and fruit crops is made up of minerals, but most modern fertilisers replace just the basic NPK (Nitrogen, Phosphorus and Potassium), neglecting the vital trace elements, such as magnesium.  The taking of crops from the land without efficient replacement of these nutrients, together with natural leaching from the action of weather, means that many soils are now nutrient deficient, which in turn implies that the whole food chain is similarly depleted.

Recently I discovered that rock dust can now be obtained that does the job of a ‘mini Mt. St. Helens eruption’ when spread on the soil — it puts back the mineral goodness that plants and ourselves need to thrive.

Rock Dust

Rock dust

In the spring I top-dressed a bed for my maincrop Kestrel potatoes using about a handful per sq.m of rock dust, raked in prior to planting.  I did see a very noticeable increase in plant health and vigour — the tops appeared ‘super green’ and lush, but the yield from one root, at well over 2 kgs, I thought was definitely impressive.  Next spring will see me ‘dusting’ the kitchen garden once again!

Rock Dust

Spreading Rock Dust at about one handful to the sq. m

Rock Dust

Raking into the surface prior to planting

Rock Dust

Potato Kestrel in growth

Rock Dust

Yield from one root of Kestrel grown on the re-mineralised ground

Wild Ferments!

Wild Ferments!

Most of us tend to view the world of microbes with some suspicion, convinced that these bugs can do us harm or make us unwell, in fact there is a whole world of beneficial organisms out there that can help us unlock additional nourishment from our food, and at the same time populate us with ‘probiotics’. Thinking about the foods and drinks we value for their taste and beneficial qualities – wine, sourdough bread, yogurt, olives, blue cheeses, to name but few – all these are created or processed with the help of the ‘good bugs’, without which many gourmet foods would simply not exist.

Almost all the traditional cultures of the world have learned independently to ferment vegetables – the French have a fermented cabbage known as ‘choucroute’, the same spoken in German is ‘sauerkraut’; right through Asia including China, Vietnam, Japan, Korea and Malaysia they make ferments called kimchi, traditionally eaten with every meal.  This lactobacillus fermentation process not only preserves the food in its raw state, makes it more digestible, but also endows it with extra nutrients and vitamins over and above that found in the original raw food. The explorer, Captain Cook, understood the benefits of fermented foods;  in the 1770’s he took 60 barrels of sauerkraut on a voyage that lasted over two years, and returned with all his crew free of scurvy, the deficiency disease that previously decimated ship’s crews on circumnavigations.

Many of the vegetables that we might have in storage from last summer are still perfect for fermenting – red cabbage, carrots, onions, turnips, celeriac, winter radish and beetroot – will all produce tangy, nutritious additions to meals. Fermented veg are used as a condiment, in the way that a small amount of chutney might accompany cold meat or a salad, rather than eaten by the plate full. The taste of them is sharp, fresh and ‘grown up’;  those with a very sweet tooth might find them an acquired taste, so if you always prefer the dessert trolley to the cheese board they may not be for you!

A great introduction to the world of fermentation is Sandor Katz’ book ‘Wild Fermentation’. This video is a talk given by him outlining basic principles:

I recently made up a jar of Cortido, the South American version of fermented cabbage, using up some of my stored vegetables in the process, and transforming them into something rather exciting! The recipe I used is from Sally Fallon’s very good book ‘Nourishing Traditions’, and her full recipe can be found online here.

Wild ferments!

Collected ingredients for Cortido

Wild ferments!

Assembled ingredients ready to be mixed

Wild ferments!

Pounding with the end of a rolling pin to release the juices

Wild ferments!

Seal the jar so that about 3 days of fermentation can begin, after placing in a warm spot


Although ferments can be started without using whey, I find the results are much more predictable if the mix is inoculated with whey. Whey? This is the slightly cloudy, yellowish liquid that can be strained out of liquid dairy products – easiest to make at home by buying a carton of plain ‘bio live’ organic yogurt and straining it using double-folded butter muslin, or a coffee filter, placed in a sieve over a container. The whey will slowly drip through, leaving you with ‘yogurt cheese’ in the filter. Whey keeps for months in a closed jar in the refrigerator.

After the fermentation period is complete, the vegetables can be eaten straight away, but taste much better after a month or two of storage – they become more mellow and flavourful with the passage of time. Just leave them somewhere cool, or if your house is too warm, then the top shelf of the fridge will be fine.

One of my favourite ferments is carrot and ginger — easy and tasty for those trying this clever technique for the first time.

Wild ferments!

Fermented Carrot & Ginger — ‘one I made earlier’


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