I’ve a workshop planned this week as part of the School of Garden Inspiration syllabus at Petersham Nurseries. The subject is bulb planting in the garden, and more specifically, Spring-flowering bulbs that are available now for planting in the coming weeks and months. Some practical information and hopefully, some inspiration along the way.
Without doubt, it can be one of the most joyous activities in the gardening year, gently burying treasure in the beds, borders, in grass and amongst wildflowers – and in containers too, for colourful, electric, elegant, soft, vibrant, cool, colours-too-close-for-comfort or wildly complimentary – accents throughout the garden and slotting in with the early perennials starting out in the early months of the year and bespoke combinations of annuals and bedding to see them from planting through to flower and a gentle decline thereafter.
No colour is forbidden and the colour-wheel can be happily abandoned. Whatever your whim and wish, just do it. Generosity is key, though simple paired-back elegance has its place too, but with a little planning and, in garden-plant-buying terms at least, very little money, you can create a floral, often scented display that can touch the coldest fringes of January and in succession, greet the Spring and even early summer in May and June.
Many bulbs can be treated as hardy perennials, multiplying and spreading as the years go by; lift and divide them and you have even more joy to pepper the garden and to share among your friends. The earliest of the bulbs on the scene, Snowdrops, fall into this generous category, as do Crocus, Cyclamen, reticulate Irises, many Narcissus, Leucojums, the summer snowflake, and Alliums most definitely. Others are very definitely annuals, or as good as and even so, should not be sniffed at. Tulips in the main fall into this category.
We happily buy pots of annual bedding, Nemesias and Petunias, Pelargoniums, Lobelia and all manner of tender, this-season-only plants that are ripped out at the end of the season. Why not then Tulips for example and we can ring the changes year on year. Bold blocks of dramatic red one year – sharp pinks teamed with almost-too-close-for-comfort oranges, doused with purple wallflowers and chartreuse Euphorbias – or cool whites and a flush of palest primrose yellow another season.
My own displays, and there are plenty of photographs in the following galleries, taken from my ‘back catalogue’ of images on this blog from 2014 through to 2017, show just what can be achieved now, for enjoyment over many months in the year to come. I’ve just posted two blogs reprising my April this year visit to Great Dixter, for great floral showmanship and a companion planting masterclass – a second blog from nearer to home and the Cutting Garden at the Nurseries and Petersham House Gardens too. They have greatly got me into the mood for some bulb action.
We will look at companion planting for bulbs, beautiful companions as well as useful disguises for when the bulb foliage itself starts to look a little past its prime. Solutions for topping off pots and planting in borders and suggestions for underplanting of mature shrubs and trees, for compliment and contrast. There are bulbs for sun and shade, so everyone can enjoy them in many diverse situations.
I have mined my own photography within these pages for a kaleidoscopic range of images featuring the earliest and latest of the bulbs I hope to introduce and elaborate, and these are roughly month to month, February to May. Depending on the season, there may be more to see in January, and more or less in May and June and their flowering companions may well be different as each season is different. Will you have Magnolia or Cherry blossom, Camellias or Rhododendrons and Azaleas, Pulmonarias, Dicentras, Hellebores, Corydalis, Peonies …?
Within the galleries, the Cutting Garden at Petersham Nurseries features regularly, from the first of the crocuses to the last of the striking Alliums. Harlow Carr, the RHS’s garden near Harrogate in Yorkshire, always puts on a fine show and RHS Wisley, back in 2014, made a very striking display. Well, they always do.
The same space earlier this week is a riot of Dahlias and I am putting together a blog featuring the Exotic Garden, Battleston Hill and the Trial Fields, the Orchards and Arboretum, Glasshouse Borders, Rock Garden, Walled Water Garden and the ‘Thinking Outside the Box’ Garden by the Jellicoe Canal. I hadn’t been to Wisley for such a long time and I am so glad to have made a brief revisit before Autumn really takes hold. So much of course going on at Wisley with lots of new building going on. See their website for further details.
But I digress. Bulbs are the order of the day and so we will start with the earliest months. I’ve put a link, at the head of the list at the end of this blog, on snowdrops, the earliest bulbs to flower and specifically the ‘Meet the Experts’ tour I took with Aaron P. Davies at Kew Gardens. It is well worth a look on the subject of the genus Galanthus.
Gallery – February 2014-17
Snowdrops are the earliest of the bulbs to bloom. There are 21 species – a new one, Galanthus trojanus has just been added, and perhaps now over a thousand cultivars. How different many of these might be is a subject of much conjecture but there is certainly a market for new, rare and more distinct snowdrops. The yellow tipped are perhaps the most sought after now, though they are also the weakest. The most expensive price for a single bulbs sold most recently was #1360 just last year.
They are the most traded, and second most traded bulbs in the world (Galanthus nivalis and Galanthus elwesii) and hail from a broad geographic region covering southern Europe, Turkey, Russia and over to the Ukraine. Millions of bulbs are traded but they are prolific and studies indicate it is sustainable, unless rarer specimens are mistaken for more common varieties and plundered ignorantly.
They are not good container plants, I might add, and are very fickle with temperatures, particularly in summer. And drying out. At Kew, they sink terracotta pots into sand, to maintain moisture and temperature but it is not ideal. In free draining, rich soil beneath deciduous trees, naturalised and allowed to colonise freely, with a little lifting and dividing by us humans to help them along, well they are much the happier for it. Anglessey Abbey, Hodsock Priory – well there will be lists in the gardening press and newspapers in January for the best places to see them en masse.
I’d take a look at my February 2018 blog from Kew Gardens when I was part of their ‘Meet the Experts’ tour, with Aaron P. Davies, who wrote the definitive classification of the genus, which he has since updated and it was a fascinating tour through the rock garden, learning much about the botanical features of the genus, and their taxonomy and geographic reach. Tim Freeth, the Superintendent of the Alpine yard took us into the Alpine yard and private glasshouses for a further tour. These ‘Expert’ tours are on every Tuesday,a different theme each month, are free but with limited numbers (about 15 only), so do make enquiries for a behind the scenes tour of many areas at Kew and a window on the work they do.
Crocus are also out and above ground early in the year and whether growing as an incandescent or luminous carpet through grass, in bare borders or potted up in shallow pans, can make a welcome display. Pure whites, flushed sometimes with colour, rich gold, primrose and purples, lilacs and sometimes, all three (Crocus tricolour), these early flowers are especially welcome. Good drainage is essential to prevent these small bulbs from rotting in winter wet, and especially in heavier clay soils.
If you are naturalising Crocus in grass, use either a half-moon edger to create a cross in the grass and lift up the corners to place the bulbs beneath the turf. Or you can use a spade to cut and lift a larger flap in the turf, before laying this back down. These are small bulbs so planting individually will be very time-consuming. Either throw the bulbs from waist height to scatter than randomly on the turf, or group threes and fives together, with smaller satellites of two nearby, to give the impression that the bulbs are colonising the space naturally. There are great carpets at Kew early in the year, and at Wisley, both close to the entrance in a wide lawn studded with conifers, and then at the top of the Bowes Lyons Rose Garden, in an area studded with silver birch and backed by dense shrubbery and evergreen Yew.
Autumn crocus are out now, with their distinctive three stamens and median white stripe on the strap-like foliage. They are distinct from the Colchicums, or Naked Ladies, which flower also now, without foliage (hence the naked bit), though they are prone to damage from bad weather, wind and rain. Double varieties like Waterlily are a little more robust, despite their bulk. I saw a beautiful collection at the Beth Chatto Gardens a few autumns ago, and they were in peak condition. They have seven stamens I think, and the leaves when they appear do not have the central stripe.
Iris reticulata and Iris histrioides offer equally miniature treasures, in rich royal-, sky- palest blues, purples and greys, and yellow flushing through some too. Small bulbs that like an open sunny site and a dry summer, with free draining soil. Perfect at the front of borders and rockeries, though top dress with a little potting grit to stop the petals, quite low to the ground, from being splashed with soil and other detritus, They can equally be potted up in shallow pans, or forming the top of a bulb ‘lasagna’ – we’ll talk about this later – they are a reliable, rich and showy bloom for early in the year. Look out for deep purple George, clear blue Harmony, Katherine Hodgkin has a pearly dull blue ground with yellow spotting and marking. Katherine Hodgkin Gold is brighter still. If you are able to get to one of the early Spring Shows as part of the RHS London roster, these diminutive and richly coloured tiny stars are out in force, from companies like de Jaeger. I’ll include a link at the end of the blog. I am still berating myself for not buying a clear yellow and blue little star called Sea Breeze. This year …
Some Narcissus might be out and about early, I’m thinking varieties like February Gold, though it is more likely to be in bloom, reliably, in March. You might find early Anemone blanda or Anemone nemerosa out early too, but again much more reliably in the following month. These latter are happier in open woodland, with richer soils, where they can colonise wide areas with delicate nodding flowers in china blues, whites and some pinks. Anemone de Caen might also find themselves out and about early, but March is a kinder month for these iridescent and brightly-hued, feathery-foliaged garden friends.
Gallery – March 2014-2018
Crocus continue on into March, to be joined by more colourful friends, Narcissus, especially the more dwarf varieties like Tete a Tete, Sundisc and Minnow. Jetfire too, with reflexed petals that make it look like it has its arms held back and shouting into a strong headwind.
Chionodoxa, the Glory of the Snow, come into colour in March, with clear starry purple-blue flowers, or white forms and pink and these are ideal for naturalising in grass, or at the front of a sunny border, or perhaps just lightly shaded, or even the Rock Garden. Most good, humus rich soils are suitable Plant 3″ deep and about the same apart.
Muscari, the grape hyacinth, also begin to flower and there are a myriad number of varieties, with clear white flowers, to deep dark blue, through pink and peppermint and even very fluffy, curiously headed flower spikes. Muscari armenaicum is the standard, Muscari latifolium, with a single leaf, has a two-tone head though is marginally tender. They are long-lasting and can be planted in single varieties, although I like to include them with Tulips and Narcissus, to break up more dominant colour themes, especially with orange and red tulips. There is a cherry tree in Wisley, with great white blooms, that is underplanted with massed muscari and the effect is always magical. it features in one of the magazines I will have at the workshop, so I hope I remember to point it our.
Hyacinths begin to make their intensely fragrant presence felt, with a wide range of colour from pure white, lemon, soft apricot orange, purples and purple-reds, soft, pale blues and rich deep dark blues and inky blacks even. Avoid the largest, tallest spikes as they can be a little heavy and cumbersome, and prone to snapping. Conversely the multiflora varieties have much looser multi-headed flower heads, much more natural and casual in appearance, and long-lasting. They look good planted in single varieties in shallow pans and traditional terracotta. They can be planted singly or in odd-numbered groups. In the garden, the fashion for ranks of soldier Hyacinths is a little over I think, but they can still be dotted through a looser bulb planting scheme, providing accents, compliment or contrast to the overall scheme, and of course the fragrance is superb. Not everyone if a fan, and indoors I admit they can be a little overpowering, but ambushed by their scent on the air out-of-doors – magical.
Bluebells, Hyacinthoides non-scripta, make their appearance in March, if they are early, and continue on through April and even May, as vigorous colonising woodlanders. White and Pink add to the mix. You can differentiate our native bluebell as the flowers congregate on one side of the stem alone, where the Spanish Bluebell, the bells are all around the stem. Both a very promiscuous, so hybridising is a fact of our native woodlands. The Spanish are moderately more vigorous, but neither are genteel and they can quickly colonise and even take over if not managed. Often, like Snowdrops, it is recommended they are planted ‘in the green’ that is in growth and after flowering but both will happily settle if planted as dried bulbs, if a little care is taken not to let them dry out completely in the summer months.
Fritillaries will make an appearance in March, and continue into April. The snake’s head or guinea hen fritillary has foot long stems and fine strappy foliage, with nodding chequer-board heads of rich plum-purples and browns. The white form breaks through occasionally from the mix, or can be bought as a pure white form, though the two will interbreed. They are fine in clay pots, where the compost is kept moist, but are ideal for naturalising in damp grassland, which they can well compete with. The area around Tewksbury is famous for them (and we can remember how much flooding that area has suffered in recent years) and I particularly enjoyed them in the East Sussex Weald, when I visited King John’s Nursery (on my blog, of course) where they peppered a rough, wild-grass meadow beneath an old orchard. The rough grass was punctuated with softly coloured narcissus, wild primroses and these beautiful fritillaries.
In March and April, two very different Fritillaries will make an appearance. The striking tiered bells of Fritillaria persica, in rich plum-burgundy, with blue-grey rings of concentric foliage. A relation, F. persica Ivory Bells, is a ghostly green-white, glaucous and despite the cool colouring, a striking plant in the border. It hates winter wet, so incorporate a little grit into the base of the planting hole especially in heavier soils, and plant the loosely scaled bulbs on their side, to avoid rot.
The Crown Imperial is another fish altogether, with a distinct foxy, tobacoo odour to the bulbs and to the flower itself. A rough of basal foliage gives rise to a tall spike topped with a ring of pendant orange, yellow or russet bells, and a pineapple-top of green foliage above. So rich in nectar, it can drip from the tips of the petals. They are good in sun and some shade – they grow them well in the dappled shade of the woods’ edge at Wisley, and among the Erythroniums (Dog’s Tooth Violets) at the top of Battleston Hill, beneath the open canopy of the pre-leaved Birch Trees.
I include them in my mixed potted bulb plantings, for additional height and fragrance amongst similarly coloured tulips, of contrasting shape and texture. These are the pots on my front path this April – mixed tulips, earlier, Hyacinths in Royal Blue, Fritillaria imperialis and purple wallflowers. The display went on from March through to May before going over.
Tulips however, and a wider range of larger-flowered Narcissus and Daffodils, are set to take the main stage in April.
Gallery – April 2014-2018
Wallflowers, Euphorbias, Alchemilla mollis, Lunnaria annual and early perennials leafing up all help to create the perfect backdrop for the kings of Spring, the volley of numerous Tulips, larger-flowered Daffs, Fritillaries on a grand scale such as the Crown Imperials, in yellow, orange and deeper orange-reds. Plant these tall, nectar rich Fritillaries in rich well-drained soil, in sun for partial, dappled shade. Plant them on their side, these loose-scaled bulbs, to prevent unecessary rotting especially in a wetter winter.
Fritillaria persica, the original purple-black towering beauty, or it’s paler cousin, such as Ivory Towers, with a cool green-white ghostly silhouette and mix in with other bulbs. Some images are a riot of colour, but look carefully, for there are complmentary colours and in one image – I think it was a front garden on Kew Green, the palette is very muted and restrained, the cool flower heads in a sea of green bolstered by topiary box balls. Restraint is in the mix too, as well as head-spinning fireworks.
As the month develops, Camassias – though I have no bulbs at Petersham; we do have them as growing plants in the early spring though – these might presage the later blue highlights to be found with Alliums and later still, Agapanthus. A softer blue than bluebells, and much taller, these naturalise well in grass as they showcase them at RHS Wisley, in a sward studded with flowering dogwoods, or at Kew, where they have a mown path cut through the near waist-high mass of hazy blue. Coming across them, you think it might indeed be bluebells, but they are just a little pale, and much much taller. They make a fine site massed together but can also be studded throughout the perennial border.
Leucojum aestevum will be in flower in April (Leucojum vernum much earlier in February, with a similar effect) tall clumps of snowdrop-like flowers, the snowflake has bell shaped flowers tipped with green, and fine strap-like leaves. It is a vigorous woodlander, happy in moist, free-draining soil and some sun.
Tulips are almost at their Zenith in the month of May and the choice is huge. Short, tall, fragrant, bright, pale, shy and retiring, fiery, single, double, fringed, parrot, star-shaped, wasp-waisted and goblet shaped, sily, pearlescent, matt, with deep green, or glaucous foliage, broad or fine.
These can be planted in large swathes, in discreet groups, as formal bedding and informal lines cutting through the perennial border and between mature shrubs. They can be dotted more sparsely through grass and wilder grass meadows. They do this at Kew Gardens, in grass, beneath a double line of flowering cherries and while they are well-spaced, the intensity of the individual blooms against the green, with the pink blossom above, there is considerable impact. Imagine double white and pink-tinged tulips beneath a cloud of white or pink cherry blossom, or pale daffodils naturalised in wilder grasses and the effect will be strikingly different.
At Alnwick Castle in Northumberland, on a hillside with a path winding, hairpinning, beneath the spready canopy of Prunus Tai Haku, the Great White Cherry, the Duchess planted a sea of Tulip Queen of the Night, a rich velvety, silkly purple-black. The effect must have been dazzling. I think I have missed my moment here as I believe the scheme has been reimagined. I shall have to make further enquiries.
Tulips in pots are an especially useful addition to the spring garden. They can be focal points, and repeated along an path, on steps, or through a border even where they can be carefully placed, create a rhythm that can be very effective.
Plastic pots can be used, as these can be simply dropped into the border, maybe partially sunk, where the leaf and flower of other spring annuals and perennials will give them sufficient volume to hide the pots. Plastic pots can be easily slotted into more decorative pots, especially terracotta, when they come into bud and flower, and then removed once they begin to go over. Potting bulbs up over a series of weeks will give a succession of flowers over a much longer period.
For almost all bulbs, and this would include Crocus, Iris, Muscari, Daffodils and Narcissus, and Tulips of course, a free-draining compost is essential. None of them appreciate a chill wet winter in damp earth and adding grit or perlite to a seed compost or good multi-purpose compost is a great start. Grit is heavier, so for pots, and especially smaller containers, the additional ballast, the weight, will also help them from being blown over in winter gales.
Pots can be planted up with single varieties and these can be very effective. For a longer-lasting display, we come to the idea of a bulb ‘lasagna’, layering bulbs at different levels in the one container, with larger, later-flowering bulbs on the lower levels, and smaller bulbs progressively above, with the smallest and quickest to bloom, at the top. It might simply be two layers, or three, or more. In substantial pots at least 50cm wide and the same deep, one might include 50-60 bulbs, though of course, the smaller bulbs like Crocus and Muscari might increase that number considerably. Shallow pans and deeper pots can be used to good effect, as I hope to demonstrate in the workshop.
Top the pots with horticultural grit, which will prevent soil splashing up onto the foliage and flowers of the merging bulbs. Cautious of the destructive advances of mice, squirrels and even birds, you might use a crown of chicken-wire over the top of the pots, kept secure until the first foliage spears through the soil before being safely removed. Planting up the pot with a variety of plants can also make something attractive from the get-go, and the underlying bulbs will have little difficulty in working their way around or through any rootballs above them. Erigeron karvinskianus (Mexican Fleabane or the St. Peter Port Daisy) can be useful. Evergreen Muelhenbeckia is a neat, evergreen and attractive plant. The variety of Pansies and Violas can be teamed to contrast or compliment the underplanting of bulbs and, often scented, will flower for weeks ahead, quieting down in the chiller months, before resurrecting into bloom come early spring.
Wallflowers are a superb companion to potted bulbs and the plants you buy in the nursery can easily be divided to make them go even further and again, you can contrast or compliment your bulbs with a range of colours, from white and lemon, through orange, scarlet, pink, purple or russets – or a mixed mix. Many are fragrant, which is always a bonus.
It is worth remembering that if the companion planting is quite diverse, it is probably better to keep the bulbs to a single variety, or close colour theme. If the underplanting is of one variety or tone, you might spruce up the bulbs planting with a little contrast. If bulbs are coming up successionally, then the effect is likely to be more streamlined, with just one accompaniment at a time to the display.
Gallery April 2014 RHS Gardens at Wisley – Kapow! Kaleidoscope! Krazy!
May brings the Allium family into play and they can easily bridge the gap between spring and early-summer, when so much else is going on. The last of the Tulips will still be in play, especially the Parrots with their extraordinary colours and forms, but to hold your own in a busy garden in May, when the early roses are having their first hurrah perhaps, peonies bloom and all manner of perennials are doing their thing, the strong form of the Allium can really make an impact.
Members of the onion family, they are generous players and will bulk up and multiply as the seasons march on. Among them are some very spectacular, tall and stately plants, with large flower heads composed of a large number of starry blooms. Others, meanwhile are much smaller. Then, if you add in the fact that they are all undemanding and hardy, it is easy so see why their popularity is increasing.
One Allium that is a must for most gardens is Allium christophii (AGM), sometimes referred to as the Star of Persia. it grows to 45cm in height, with strap-like glaucous, grey-green foliage. The large rounded flowerhead which can be 15cm or more across, is made up of star-shaped silvery pink blooms. They appear in mid- to late Spring.
This is also the time when Allium karataviense 9AGM) produces its white flower heads, slightly smaller than A. christophii, on20cm stems.
By contrast, Allium sphaerocephalum, the drumstick Allium, has compact flowerheads of purple-crimson on 50cm stems in late spring.
If you are looking for something different, Allium schubertii has huge heads of bright rose-red individual tubular blooms on long pedicels in early summer, but on short stems. The widely-spaced flower heads sit low down on their foliage. I saw a particularly effective use, featured in the following gallery, where they were planted amongst lavendar beds and the effect was very beautiful.
Unquestionably impressive are the densely-packed 15cm wide violet flower heads of Allium giganteum (AGM) in early summer – a native of the Himalays it can reach 1.2m in height. Another to look out for is Allium Globemaster 9AGM), the enormous violet heads are 20cm across and produced on long strong stems.
Allium atropurpureum is later flowered again – in early to mid summer, each upright stem is crowned with a rounded cluster of small flowers, which seem to hover like large, brilliantly coloured jewels above the foliage. Each flower is made up of deep pink to purple petals surrounding a blueberry-purple centre, which creates a vibrant and exciting contrast of colours. Their drumstick shape is great for adding diversity to the border, while their sturdy stems makes them ideal for cutting. If left in the border after the flowers have faded though, the subsequent seed heads will add months of structural interest. Indeed, many alliums seed freely but if you deadhead, then more goodness is returned to the bulb and that often is a key feature of many bulbous plants.
My favourite though will be Allium Purple Sensation, shorter stemmed and sturdy, with violet-purple bright compact flower heads and a generous habit of multiplying freely, they represent excellent value for money and make a striking addition to the late Spring and early summer border. They have a striking silhouette which makes them particularly well suited to gravel or prairie-style planting schemes, but they also look great in pots or mixed borders. Their densely packed umbels of deep violet, star-shaped flowers appear in early summer above strap-shaped grey-green leaves.
The leaves of all Alliums start to die off as the blooms mature, so a skirt of fresh herbaceous or grassy foliage will help disguise their decline, with the flower heads high and proud on their sturdy stems.
Gallery – May 2014 – 2017
Feeding after the flowers begin to fade is a bonus, and do not tidy way the failing foliage but let is fade gently while still nourishing the bulbs. Deadhead to prevent excess energy being drained from the bulb itself but leave on the foliage – and do not tie it into knots please.
Tulips, if it is possible, should be removed as for the most part, species varieties aside, and some more perennially natured varieties such as Spring Green, are unlikely to give a good showing the following year. You are more likely to suffer rot, and perhaps the pernicious Tulip Fire, a botrytis mould for which there is no cure, or other virus for which tulips may be prone. All else can reliably be left in situ for another year. Potted bulbs, save for tulips, might be reasonably planted out into the garden, so that they can enjoy more generous accommodation and be respectably expected to put on a good show thereafter year on year.
I should mention tools, a the workshop, though really nothing too specialised is needed. There are bulb planting tools, and depending on your soils, these can be a bonus or source of deep disatisfaction. A good, perhaps a good narrow trowel, a half moon edher and a spade should be sufficient for more purposes. And determination!
Timing too, very important so I shouldn’t forget this – especially in relation to Tulips. Buy them now by all means, when the choice is there and the bulbs are fat and solid and ready to go – but wait a few weeks please for these particular bulbs. Much cooler weather will do them a treat, even a frost or two which will kill some of the troublesome characters like Tulip Fire, and prevent the little things from thinking it is spring already and bolting out of the ground before their time. Pretty much everything else can go into the ground, or into a pot right now. They like a good slow burn, knitting themselves into the soil and developing a strong root system that will see them well for their performances next year. No doubt I shall think of a few other essentials, or be reminded of them in the Q&A after the workshop. If there is more to add, be assured I shall update this post ….
Well I think I shall leave it here for the moment. This is a diverse and rich subject and I end with a few links, which I think merit further investigation. An article to finish by Monty Don, elaborating on the differences between true bulbs, corms, tubers and rhizomes, for whom the term ‘bulb’ is not nearly sufficient enough!
On distinguishing between Bulbs, Corms, Tubers, and Rhizomes
I would imagine there has been a frenzy of excitement down at Observer Towers with the new format, new year, new mood of energy and hope, but these things have quite passed me by here in the sticks. But things are stirring in the undergrowth, alas, in exactly the same format that they have boringly persisted with for the past millennium or so. The snowdrops are still green bullets piercing frozen soil, but it won’t be long before they flower, with aconites close behind them. Over the next three weeks I shall be focusing on growing bulbs for every season, and now is a good point to start, when the early spring bulbs seem a possibility rather than a promise.
Bulbs are packed with flowers. That is their magic, especially in spring when flowers are scarce. In fact, it takes well into June before flowers start to dominate over foliage, so a bulb, however small, can provide pure colour, be it the blue of scillas, the gold of daffodils or the whole rich palette of tulips. Planting bulbs is all about setting a detonator for colour, and anyone can put that explosion where they want it, and with a little experience, research and selection you can also time it for pretty much when you want it.
Let’s start at the beginning. ‘Bulb’ is a generic word to cover those plants that store their next season’s flower and the nourishment to grow it within a self-contained capsule that can survive until the following growing season without nutriment or roots. The true bulbs – such as tulips, alliums, Iris reticulata I unguicularis and daffodils – are essentially a very reduced stem made from concentric layers of fleshy scales with a dry, protective outer layer. Each scale is either the base of a leaf or the thick-scale leaves that never appear above ground. The paper outer layer is the remains of last year’s scales. Bulbs tend to be smooth and, er, bulb-like. However, some bulbs, such as lilies and fritillaries, have no protective skin and the scales are separate. There are three distinct forms of bulb. In the most common – such as tulips or alliums – the bulb shrivels and dies after flowering and is renewed from buds formed at the base of the scales at the point where they join the basal plate. Narcissi, on the other hand, do continue year on year, producing offsets rather than wholly renewing themselves. This is why you get ever-increasing drifts of vigorous daffodils, but tulips tend to increase more reluctantly and with a marked loss of vigour as it takes two or three years for most tulip bulbs to flower. The final type of bulb, such as Hippeastrum (amaryllis), has embryonic bulbs for three years ahead within each ‘parent’ bulb – so it is genuinely perennial.
Then there are corms, like the iridaceae family – which includes iris, gladioli, crocus, crocosmia, freesia and dierama – which form themselves anew each year on top of the old one, looking like an unwrapped packet of fruit pastilles, as corms are all distinctly flattened on the top and bottom. They are also wrapped in a dry, protective layer of old leaves. They make cormels – mini corms – as offsets during the growing season; these can be separated and planted out without damaging the parent corm and are a very good way of propagating the plant. Corms, such as erythroniums, develop as offsets so the colony can spread while the parent grows larger each year.
Tubers differ from bulbs and corms inasmuch that they are not the base of the stem but the swollen roots that are used for food storage – unlike most roots, which are solely a medium for conveying food to the plant. The old tubers die after flowering and new ones are formed throughout the growing season, which is why you should never lift or cut back a tuberous plant, such as a dahlia, until all growth has finished for the year. Tubers are found in some orchids, in dahlias, anemones, corydalis and in cyclamen species, as well as, of course, the potato.
Finally there are rhizomes, which are swollen underground stems, usually horizontal, always very shallow (sometimes on the surface of the soil). The best-known examples are bearded irises, Anemone nemorosa and lily of the valley, as well as ginger and couch grass.
In an ideal world, the best time to plant bulbs is when they are dormant between accumulating energy for next year and starting growth. But ideal times tend to either take us unprepared or ringed round with smugness. I have been doing this sort of thing for well over 30 years and have not mastered the ideal timing yet. The truth is that it is not too late to plant spring bulbs – but get on with it. Tulips are very comfortable with a January planting, but crocus and narcissi are likely to do better in their second season than first if planted later than November. Snowdrops and aconites are much better planted ‘in the green’, by lifting and dividing existing plants just after they have finished flowering – which in most cases will be early March. If you plant them as dry bulbs the failure rate can be horrendous.
The general rule for planting all bulbs is to go rather deeper than the obvious. Two or three times the depth of the bulb itself is the usual guide, although that means too much measuring for me. The guiding rule is that you will do less harm by being too deep than too shallow. However, do not agonise over this. Plants are always tougher than you think.
The other general rule is that bulbs need good drainage and this is vital for ones like tulips, alliums and Iris reticulata. The best way to ensure this is to mix loads of grit into the general area or container (50:50 grit to potting compost is none too gritty) they are to be planted in, or to add a good dollop of grit in every planting hole. Tedious but worth it. Some spring bulbs, such as snowdrops, fritillaries, eranthis and, in my own garden, muscari seem to thrive in quite damp conditions. But all these like a humus-rich, fairly free-draining soil.
All bulbs look good in a container, particularly terracotta pots. These can be moved into sunshine or shade as required and can also be guaranteed to provide the right kind of drainage. Pack smaller bulbs in tightly and try and find shallow alpine pans, which are the perfect container for crocus, snowdrops, fritillaries, iris, muscari and other small bulbs. Remember that most will need a summer baking so make sure they have some sunshine when dormant.
Ideal soil conditions
Fritillaria meleagris damp
Iris reticulata/unguicularis well-drained
Snowdrop moist shade
Corydalis solida any good soil
Colchicum hungaricum well-drained
Anemone nemorosa well-drained