Photography by Jason Ingram

White magic: how to propagate snowdrops

Margaret and David MacLennan have built up a collection of more than 2,000 snowdrop cultivars, with their success due in part to the deftness of Margaret’s nimble fingers when it comes to propagation. Words Rory Dusoir, photography Jason Ingram.

About Margaret and David MacLennan

Margaret and David MacLennan introduced themselves to the esoteric pursuit of collecting snowdrops just over 15 years ago. They now grow at least 2,000 distinct cultivars of Galanthus and theirs is the largest systematic and publicly accessible collection in the UK. As a National Collection, it was granted Scientific Status by Plant Heritage a few years ago, in recognition of the MacLennans’ extraordinary rigour in maintaining, expanding and documenting the collection, but also of their generosity in sharing knowledge and plants among other enthusiasts and institutions. David has an impressively easy command of the niceties of form and lineage that distinguish each snowdrop in their collection and photographs them assiduously, while Margaret’s skill as a propagator has been central to the MacLennans’ rapid ascent among galanthophiles.

Starting the process

The first priority on acquiring a new snowdrop is for it to reach blooming size so that it may be observed and photographed in flower. In its first dormant season after flowering, Margaret will put the bulb under the knife. Having cleaned the bulbs carefully with methylated spirits, she ‘chips’ them by first cutting the top off, then making a number of axial incisions from the bottom to the top, to produce eight or more propagules (viable pieces of bulb), each with a portion of the root plate intact. Margaret normally stops once she has eight pieces of bulb.

It would be feasible to divide these further to an almost indefinite extent, by making further axial ‘chipping’ incisions, or by ‘twinscaling’. This involves making further longitudinal divisions, but with the knife running perpendicular from the previous ‘chipping’ cuts to separate the bulb ‘leaves’ from one another, again ensuring that there is some root plate attached to each piece. However, as Margaret points out, the smaller the propagule, the longer it will take to flower again.

Preparation process

The ‘chips’ are then soaked in a fungicide solution for 20 minutes and placed in a sealed container with a layer of vermiculite above and below. The boxes are placed straight into a large propagator in darkness and held at 21°C for 12-14 weeks, during which time they will all be checked every few days – pieces that show any sign of infection will be immediately discarded before the rot can spread.

After this they are ready for their first potting up, into 9cm square pots. These young bulbs are kept frost free for their first winter. Ultimately, flowering-sized bulbs ready to take their rightful place in the collection are housed in aquatic baskets plunged into sharp sand in cold frames – this allows the snowdrops’ annual root system to roam freely beyond the confines of the pot, while keeping all the cultivars safely segregated (bulbs tend to roam in the open ground). The ‘reservoir’ effect of plunging the pots, combined with the high rainfall in Carlisle, mean that the snowdrops never have to be irrigated.

Organic way forward

The MacLennans used to grow their snowdrops in a John Innes mixture leavened with grit, leaf mould and perlite, but after a successful trial they are now making a transition to bulb compost manufactured by Dalefoot – an organic and peat-free compost produced sustainably in the Lake District that contains locally sourced sheep’s wool and bracken. As well as being fertile enough to sustain a pot of snowdrops without feeding for a couple of seasons, the compost is also light – a crucial consideration when maintaining a collection on such a considerable scale. The bases of the bulbs are placed on a layer of sharp sand within the compost and re-potted at a maximum interval of three years. All the propagation and re-potting must take place during the snowdrops’ dormancy, between May and September.

How to propagate snowdrops

1

Margaret MacLennan propagating a snowdrop

After removing the top quarter of the bulb (cutting parallel to the root-plate), make the first longitudinal cut to divide the bulb into two equal pieces.

2

Margaret MacLennan propagating a snowdrop

Bulbs can be divided into four, eight, 16 or 32 equal pieces (‘chips’) of bulb, ensuring each has a portion of the root-plate attached. Margaret seldom divides a bulb into more than eight chips as smaller divisions take longer to reach flowering size.

3

Margaret MacLennan propagating a snowdrop

For twinscaling, further longitudinal incisions may be made to divide the chips into separate bulb ‘leaves’ or ‘scales’, with the blade perpendicular to the axis of the ‘chip’ of bulb.

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Margaret MacLennan propagating a snowdrop

Soak propagules in a fungicide solution for 20 minutes and place in a sealable container on a bed of vermiculite. Add a covering layer of vermiculite then seal the box and keep it somewhere dark at 21°C. Check every few days for rot, but after 12-14 weeks they should be ready to pot up.

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Useful information

David and Margaret do not hold open days, but when regulations permit they open their garden by appointment to groups only. Find details on the Plant Heritage website plantheritage.org.uk