Plant profile:
Grown under trees or naturalised in grass in these unassuming, flowering bulbs bring a wash of colour to early spring
Scilla Plantsman John Grimshaw recommends the best of these unassuming, spring-flowering bulbs that a wash of naturalised colour
Amongthe abundant whites and yellows of early spring a pop of other colours is welcome, and none more than blue. Here the genus Scilla comes into its own, briefly spangling the ground with its six-petalled flowers in shades from glacier- to Prussian blue, varying sometimes to white or pink, occasionally almost mauve. None lasts very long in flower, and most would not draw a crowd, but as highlights in the garden, or as gems in a pot, they are delightful.
The name Scilla has been in use for hundreds of years, originally being applied to the Mediterranean sea squill, now Urginea maritima, a tender, autumn-flowering bulb with long spikes of white flowers, but Linnaeus brought this together with an assortment of smaller, blueflowered plants more representative of what we call Scilla today. The standard English name is squill, but it’s one that you don’t often hear in use; most gardeners call them scillas.
The genus has been used over the centuries as a bit of a ragbag, and its constituents have always been in flux. As an example, gardeners may be surprised that the plants they’ve always known as Chionodoxa, or glory of the snow, have recently been included in Scilla, but the distinctions were always slight and they hybridise very easily with Scilla bifolia, the type species of the genus, so they have been united with it. Others, more disparate, now appear in segregate genera accepted to varying degrees by botanists; the autumn-flowering native Scilla autumnalis is placed in the genus Prospero, for example, and African former scillas are in Ledebouria and Merwilla.
The plants grown as Scilla today come from a wide a wide swathe of Europe and west Asia from southern Spain to the Caucasian forests in Iran. Some, such as the large S. peruviana despite its misleading name, are from the Mediterranean lowlands and like a hot summer. Its richblue, starry flowers start opening as the flower stem is nestled within the rosette of leaves, but the stem elongates as flowering progresses, as it does in most scillas. Most of the other species are from alpine or woodland habitats. Some years ago, while driving across Germany in March, I was surprised to find the tiny blue stars of S. bifolia in a service station hedgerow, but its range covers suitable habitats across Europe from Portugal to Turkey, but not Britain, though it makes itself very happy here. There are beautiful swathes of it under the trees at Hergest Croft Gardens in Herefordshire.
As garden plants, scillas are best allowed to naturalise. Perhaps the classic species is S. siberica, with nodding, rich-blue flowers in March – the name is a little misleading as it comes from no further east than the Caucasus. When happy it will self-sow to create a great carpet – the best I have ever seen were in Massachusetts in northeastern USA – ideal in thin grass or under deciduous trees and shrubs. Another that rapidly spreads in the same conditions is S. bithynica, with pretty, starry, softblue flowers but large, coarse foliage that can smother other things; only plant it if you have plenty of space. Much more staid, and one of my favourites, is Scilla ‘Pink Giant’ (formerly Chionodoxa) with large, solidly pink flowers that really make a show in the garden or in a pot. One of the most useful features of all the small scillas is that they are truly ephemeral, popping up to flower and often completing their entire growth cycle in less than two months before discretely melting away as other plants rise above them.
• Author John Grimshaw is director at The Yorkshire Arboretum.
His recommendations for the best scillas can be found over the next five pages.
Cultivation
For a big, bold effect, some scillas can be planted densely in grass to create a blue river, but I prefer to see them in what Arabella Lennox-Boyd calls millefiori plantings, creating a changing spring carpet of ‘a thousand flowers’ in short grass under shrubs and trees. Choosing species carefully makes it possible to have a long season, starting with the icy pallor of
S. mischtschenkoana ‘Tubergeniana’ in February, opening at ground level with Crocus tommasinianus before the stems elongate to their full height of 10cm, and continuing well into May with the upright spikes of S. litardierei. In one of my favourite plantings, at Colesbourne Park in Gloucestershire,
S. luciliae is sprinkled through short grass full of native primroses (Primula vulgaris), wood anemones (Anemone nemorosa) and celandines (Ficaria verna), creating a mesmerising effect for just a few days each spring.
For naturalising, scillas should be planted as generously as possible, flung out to plant where they fall, in hundreds or thousands. Ideally the tip of the bulbs should be about 2.5cm below the surface, but there’s no point in precision with such things. Scillas have the capability to adjust their depth in the soil by means of contractile roots that pull them deeper if necessary. The next generation of seedlings will suit themselves and flower in three or four years, so the patch should spread quite quickly in good conditions.
As with most bulbs, scillas don’t thrive in heavy clay, or permanently wet places; well-drained soil of any type will suit them well. They should have plenty of light in the growing season, so avoid planting them under evergreens.
To really make a show when potting scillas, pack them densely in the pot as the display will not last long, especially if brought inside. Don’t try to force them too much; plunge the pots outside and only bring them in when the noses are showing – they will rapidly develop and come into flower with a slight increase in temperature. Afterwards place them back outside and continue to feed and water them for the rest of the growing season. In a mixed planting, use them as the top layer of the ‘lasagne’ with larger and later-flowering bulbs below.