Mystery of autumn crocuses

Press, 11 February 1983, Page 12

Mystery of autumn crocuses

One thing leads to another when it is time to lift the bulbs.

WARDENERSI W DIARY

Derrick Rooney

Late summer is bulb-lift-ing and replanting time, and also the time when confusion starts all over again for many gardeners. It’is very easy, unless you take careful precautions, to mix one batch of dormant bulbs with another. It is very difficult, unless you have made a point in previous years of lifting them regularly and memorising their characteristics, to distinguish, say, a small scilla bulb from a chionodoxa, of a romulea from a gladiolus.

Or the autumn crocuses from the “autumn crocuses.” Confusion in the latter case arises from the habit of many gardeners, of attaching the name "autumn crocus” to the species of colchicum which flower in March and April. Quite why this practice arose of attaching the generic name of one plant to the popular name of another,

totally unrelated, plant is a mystery.

Perhaps some nurserymen have difficulty spelling “coldricum,” or their customers have difficulty pronouncing it.

Apart from the fact that there are probably more species of true crocus which flower in autumn than there are colchicums, the differLences between the two groups of plant are clear cut. For starters, most colchicum species have flowers bigger than those of all crocuses. For seconds, the two belong to entirely different plant families: colchicums are related to lilies, crocuses to irises.

Colchicums have enormous, coarse, deep green leaves which do not appear until spring; crocuses have narrow, grassy leaves, often with a pale central stripe, which appear with or just after the flowers. Colchicums have enormous, misshapen corms, often with a protruding “foot”; . crocuses have small, round or flattish ones.

This having been said, I hasten to add that while there is no room for confusion between the two genera, they offer, individually, ample opportunity for muddlement. Take Crocus salzmannii. the most common (in New Zealand gardens) and in many ways the most satisfying of the "true" autumn crocuses.

In the common form, which I have grown for many years, it has enormous corms, as big as daffodil bulbs, covered with a tough, stringy, khaki tunic, inside which are layers of softer, creamy tan fibre. Clearly these are designed to protect the corm from something: excessive damp, heat, or cold, your guess is as good as mine. People often plant this crocus in a hot, bare part of a rock garden, then wonder why it fails to thrive. My experience with it has been that it is one of the few crocuses which do better when grown in semi-shade, or where tall herbaceous plants will shelter it from the summer sun until it is ready to flower in late autumn, by which time the perennials will be ready for felling. It multiplies at a most satisfying rate, and flowers freely in late March or April. The leaves emerge before the flowers, which is probably significant, because one of the points to look for when identifying autumn crocuses is whether the flowers appear before the leaves, vice versa, or simultaneously. But this is the only aspect of this plant which corresponds with what has been written overseas. The two classic works — E. A. Bowles’s "Handbook of Crocus and Colchicums" (London, 1924) and Louise Beebe Wilder's "Hardy Bulbs" (New York. 1936) — both speak disparagingly of the flowers of Crocus salzmannii: "Of rather thin substance and a washy pale lilae 5 ’ (EAB) and “poorly coloured and thin in texture, with narrow segments” (LBW). The plant grown in New

Zealand has large flowers of good substance and weather resistance, and the colour, though pale, is a clear lilac; nothing washy about it. The throat is yellow, and the petals do not have the darker feathering characteristic of most other coloured autumnal species. Possibly what we have is the plant listed by Bowles, but not very clearly described. as the variety erectophyllus. This, according to him, was not traceable to a wild source but appeared to be intermediate between Crocus salzmannii and the more northerly species, Crocus asturious. and might be from central Spain. At this point the gardener can’t help getting into a muddle. Item one: The name Crocus salzmannii has. since Bowles’s book was published, been consigned to limbo — its name has been merged with that of the more widespread (in the wild, not in gardens) Crocus serotinus, and C. salzmannii is now a mere subspecies. Serotinus, incidentally, means lateflowering.

Item two: Bowles was quite specific about the plant he listed as Crocus salzmannii, saying it grew in southern Spain near Malaga, in Gibraltar, and in North Africa near Tangiers. and noting that it had the largest corms of all crocus species. Item three: Chris GreyWilson’s admirable book “Bulbs of Europe" (1981). listing the revised names of European crocus species, gives the distribution of “Crocus serotinus ssp. salzmannii ” as Western, Central, and Southern Europe. No mention of a large bulb. Aha! A clue!, Suddenly it becomes clear that what we have is almost certainly not a plant typical of Crocus salzmannii as it grows wild in Europe but a localised and aberrant form that some itchy-fingered botaniser in time past dug from a Spanish hillside.

I suspect that many of the “species" grown in dur gardens originated in this way — by being picked out by some sharp-eyed plant hunter for a particular floral or vegetative quality that made it a useful garden plant but not necessarily a typical representative of the species. I venture to say that only a handful of our "garden species" of crocuses are typical of the wild species as they are described in the botanical floras.

For this reason I no longer bother to puzzle for hours over my books to put names to the crocuses in my rock garden. But I keep the books as a general guide to what I might expect from, for example, new bulbs, or bulbs raised from seed. Names don’t matter too much, anyway, because with

a few exceptions (e.g. big white caspius in autumn, little white ochroleucus in winter, bright orange vernus in spring) one crocus species is pretty much like another to the non-expert eye.

In some cases the correct identification rests on minute points that can be determined only with the aid of a powrful lens. It’s actually easier to separate one species of crocus from another at lifting time in summer than at flowering times. Most have distinctive corms.

Some species, such as Crocus salzmannii (or what-have-you) have flattish corms covered with fibrous tunics — straight fibres in this case, or woven like a minute fishnet in Crocus medius. Others have corms covered with coarse weave.

Some have clearly distinguishable annual growth rings; these are very prominent in Crocus chrysanthus, which has roundish corms, flattened top and bottom, with a leather-hard, smooth tunic, often bicoloured. Crocus zonatus has wide, flattish, asymmetrical corms, with a scaly, white outer sheath and a thin, shiny, inner tunic, plus the habit, unusual in crocuses, of multiplying like gladiolus, forming innumerable "rice grains” which are only too ready to drop off and take root whetever they land; if you grow this species, isolate' it from other crocuses.

Crocus laevigatus has hard, shining little corms that look just like tulips — and have fooled me. especially in the variety fontenayi, which is winter-flowering and has rosy-lilac flowers, with a buff exterior heavily feathered with purple. If I hadn't labelled it I would have sworn it was a good, early-flowering form of Crocus imperati. However, in spite of the floral likeness they are different plants, because Crocus laevigatus comes from Greece, whereas C. imperati is confined to a small section of western Italy, in the region of Naples — a Neapolitan crocus yet! If I ever manage again to find one of my bulbs while it is dormant I shall plant a few with the Neapolitan cyclamen. which, if we are to comply with recent revisions, we must now call Cyclamen hederifolium instead of by the familiar name. C. neapolitanum.

Of course they won’t flower together, because Crocus imperati does not

come out until late midwinter, whereas the cyclamen is one of the earliest of the autumn "bulbs” and its flowers, in shades of pink and white, are already poking through the soil. This looks like being a vintage year for cyclamen, which are popping up in unexpected places all round the garden. Even a edrm in a raku-fired pot which in spring had given every appearance of being moribund (I blamed something in the glaze for the sudden demise of its foliage) is coming to life again. Crocus imperati. incidentally. is one of a large group of ’ closely related species from Eastern and Southern Europe which, if they flowered simultaneously, would be difficult if not impossible to separate. They include Cc. suaveolens. dalmaticus, minimus, corsicus. and etruscus. I don’t have a corm of C. imperati in front of me, but as I recall they are covered with coarse fibres.

I am looking at corms of Cc. corsicus and dalmaticus. Those of the former are turnip shaped, wider at the bottom and slightly offcentre at the top, and loosely covered with stringy, parallel fibres beneath which is an inner tunic, smooth and pale brown. Crocus dalmaticus corms are flattish, wider at the top than the bottom, with a coarse outer tunic of parallel fibres, a finer middle tunic, also of parallel fibres, and a smooth, light brown skin underneath.

These are among the bulbs that I grow in pots, and when they flower it is difficult (I am tempted to say impossible) to distinguish one from the other. All of this should make it clear that a gardener who really knows his onions about crocuses should have no difficulty in identifying most, maybe all. of the cultivated species in their off season without any reference at all to the size, shape, and colour of their flowers.