The delights of dahlias

Red dahlias with green leaves

Dahlias add height and dimension to borders and containers
Image: Phillippa Lambert

After languishing for a while outside garden fashion, the dahlia’s return to popularity is long-overdue and much deserved! Long flowering (June to early December in a sheltered spot), easy to grow, invaluable in the summer border, and 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. Here’s why every garden should have some dahlias and how to propagate your favourite varieties.

Browse our full range of dahlia tubers for even more inspiration.


Weaving the Garden Tapestry

There can be much more to a beautiful garden than masses of flowers.  Although a ‘sea of colour’ border is spectacular it may be fleeting in beauty, and can lack definition through the seasons if it has no underlying form or structure.  

Putting together the shape and outline of different types of plants to create harmonies and contrasts is what can give a garden a distinctive, cohesive look.

Fatsia japonica and Mahonia ‘Soft Caress’

©Steve Lambert, Lake House Design – A ‘green on green’ combination gives a subtle harmony of two hardy shrubs that will both cope well with shade; left is Fatsia japonica (False Castor Oil) sporting glossy, broadly fingered leaves, while to the right is the newish Mahonia ‘Soft Caress’ delicately feathery and full of grace.

Plants are endlessly varied in their forms, ranging from the vertical spires of narrow conifers, down to the mounded shapes of Lavender, giving way to the creeping horizontal mats of Ajuga and Thyme.  Feathery Fennel emphasises the strong form of Phormiums.  Wispy grasses intensify the solidity of leathery Hosta leaves.

Phormium ‘Black Adder’ and Plectranthus argentatus

©Steve Lambert, Lake House Design – Some of the most dramatic plant groupings involve a number of different contrasts, in this case of light and dark, as well as of form — skyrocket verticals set against a softly rounded mound. The wonderfully glossy rich purple Phormium ‘Black Adder’ is underplanted with the felted leaves of Plectranthus argentatus in one of its variegated forms. The Plectranthus hales from Australia and is not hardy (kept from year to year by cuttings in the Autumn), but similar effect would be to substitute the hardy Brachyglottis ‘Sunshine’ (formerly Senecio)

Playing with the geometry of nature, in juxtaposing plants with differing forms and habits delights the eye, and gives the planting a clear framework on which to build the more ephemeral delights of colour and scent.  In other words, the way plant varieties are grouped together is the essence of great gardening.  

Phormium ‘Rainbow Sunrise’ and Canna ‘Australia’

©Steve Lambert, Lake House Design – Another dramatic phormium grouping see Phormium ‘Rainbow Sunrise’ against the rounded leaves of the dark Canna ‘Australia’. This duo also gains resonance from the tone on tone colouring of the two plants together.

Although it is a daunting prospect to tackle the redesign of an established garden, in reality plants come and go.  Once you have finished mourning the loss of a favourite plant, the realisation comes that each demise gives a chance for a little improvement to the scheme, by then making a more considered choice of replacement that will enhance and resonate with its neighbours.

Carex trifida and Rogersia aesculifolia

©Steve Lambert, Lake House Design – A waterside grouping sees a ‘fountain’ of the variegated grass Carex trifida intertwined with the hand-like leaves of Rogersia aesculifolia, delighting the eye from early Spring to late Autumn. Plants adapted to wet or damp conditions often have lush expansive leaves, giving scope for the most interesting foliage combinations.

In small gardens already furnished with many favourite plants, and new ones just waiting to be to tried out, it is tempting to plant just one of each variety, but one plant very rarely looks good — unless of course it is a ‘specimen’ with dramatic or sculptural form.  The ‘one of each’ policy can produce a ‘spotty dotty’ look that is visually too restless, with no repose for the eye.

Dicksonia antarctica mingles equally well with Darmera peltata and Astelia chatamica ‘Silver Spear’

©Steve Lambert, Lake House Design – Foliage plants alone are perfect for furnishing parts of the garden, especially shady areas, which are intended to be calm and restful. The delicate, acid green fronds of baby tree ferns (Dicksonia antarctica), can contrast equally well with the rounded, handlike leaves of Darmera peltata, or entwined with the strappy spikes of Astelia chatamica ‘Silver Spear’. Interestingly the Astelia, although adorned with glossy silver leaves, does very well in shade, whereas silver-leaved plants usually need full sun.

The key to an harmonious effect is to gather up smaller plants or shrubs in three’s or five’s of one kind, and then use these groups, set against one another, for maximum effect.  Luckily the smaller plants are often very easy to bulk up by splitting clumps, or taking cuttings, ensuring planting for style and substance does not dent the budget too much!

Heuchera 'Big Top Bronze' and Saxifraga stolonifera

©Steve Lambert, Lake House Design – A subtle combination of two ground cover plants for shade, both with attractively veined leaves. Above is Heuchera ‘Big Top Bronze’, underplanted with Saxifraga stolonifera giving a subtle interplay of scale, tone and form.

Making patterns with leaf colour — the subtle interplay of greens, or silver, or gold — is a never-ending pleasure that ensures a furnished garden even in the darkest months, without the need for the fleeting attraction of flowers.  Just as interesting are the many forms and textures of foliage, from the shiny and glistening spears of Astelias, through to the furry felted mats of Stachys byzantina (Lamb’s Ears), via the satiny leaves of Heucheras, and the broad ribbed leaves of Hostas.  Essentially texture gives us contrast of rough with smooth, matt with gloss, as well as providing another level of interest, that of sensation and touch.

Hosta ‘Sum and Substance’, Chionochloa conspicua and Libertia ‘Goldfinger'

©Steve Lambert, Lake House Design – Scale and form again relate to good effect in this grouping of grasses and hostas. The solidity of the massive plate-like golden leaves of Hosta ‘Sum and Substance’ point up the wispy drooping heads of the grass Chionochloa conspicua (to the right) and give a background of contrast to the ribbon leaves of the grass-like plant Libertia ‘Goldfinger’, to the left.

Endless permutations of form and the subtleties of foliage texture can be harnessed to make the building blocks of a great planting — the answer then is to ‘compare and contrast’ for stunning, enduring effect in your outside space!  

Pennisetum macrourum and Tetrapanax papyrifera

©Steve Lambert, Lake House Design – Playing with scale is another great strategy to give interest and depth to borders. Here the feathery uprights of African feather grass Pennisetum macrourum, are delicately poised against the massive solidity of a Tetrapanax papyrifera leaf. As the Tetrapanax is not especially hardy, in more exposed gardens The False Castor Oil, Fatsia japonica would have somewhat the same effect. The Pennisetum started out as a single plant in the previous year, but was split in the spring to make a substantial group of three plants.

Pennisetum ‘Tall Tails’ and Astelia chatamica ‘Silver Spear’

©Steve Lambert, Lake House Design – No other plant gives the same effect as grasses in the landscape of the garden with their fluttering leaves catching the light, or passing breeze. Grasses are generally pest-free, need no staking, have a long season of beauty, and, if carefully chosen, add airy elegance to a scheme. Here the fountain effect of Pennisetum ‘Tall Tails’, in the foreground, is contrasting with the sword-like silver leaves of Astelia chatamica ‘Silver Spear’.

Tetrapanax papyrifera and Begonia ‘Benitochiba’

©Steve Lambert, Lake House Design – Gardening in smaller spaces, using groups of pots on paving or decking, can still offer opportunities to play with leaf shape and colour. Although flowering annuals are the usual way to furnish pots for the summer, foliage plants have a long season of beauty and are less demanding of care and deadheading. Here a young Tetrapanax papyrifera, is teamed up with the gloriously metallic, net-veined Begonia ‘Benitochiba’.

Begonia luxurians and Canna

©Steve Lambert, Lake House Design – Another idea for a foliage pot sees Begonia luxurians planted up with a dark leaved canna. The fingery brillant green leaves, against the solid ‘paddles’ of the canna would enhance the tiniest garden and give pleasure from May to October.

Sellonia ‘Richardii’ and Bergenia ‘Bach’

©Steve Lambert, Lake House Design – A telling foliage contrast sees the needle-like leaves of the small pampas grass Sellonia ‘Richardii’ poised elegantly above the robustly shiny ‘plates’ of Bergenia ‘Bach’. Both these plants are not fussy as to soil, put up with a certain amount of shade, and have a long season of interest, both in foliage and flower.

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.


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

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