Crown imperial (Fritillaria imperialis)
Fritillaria imperialis, commonly known as crown imperial, is a bulb native to mountainous regions in Turkey, western Iran and eastwards to Kashmir. It is grown for its large and spectacular clusters of bell-shaped flowers in late-spring.
Quick facts
Botanical name Fritillaria imperialis
Group Bulb
Flowering time Spring
Planting time Autumn
Height and spread 100cm (40in)
Aspect Sun
Hardiness Hardy
Difficulty Moderate
Cultivation notes
Crown imperials are strong-growing bulbous plants, making rapid growth in the spring, flowering during April/early May and dying down in early summer.
Planting
They need a deep, rich, well-drained loam soil, preferably alkaline, and a warm, sunny position where they can be left undisturbed for many years.
Where soil conditions are less than ideal it is advisable to thoroughly prepare the site before planting, digging in some well-rotted manure or rich leafmould and grit. Simply putting grit in the bottom of planting holes on heavy soils will achieve little. Add a dressing of Vitax Q4 Fertiliser at about 140g per sq m (4oz per sq yd) before planting in the early autumn.
Plant
It is claimed that planting the bulb on its side may prevent rot when the bulb is dormant during the summer. Over a season, however, bulbs tend to right themselves.
Add a mulch of well decayed
Containers
Crown imperials rarely do well on heavy clay soils and, in such situations, are best grown in raised beds with good drainage or in containers. For the latter, use a mix of equal quantities of John Innes No.3 and multipurpose growing media with the addition of about 20 percent grit. Incorporate Vitax Q4 at 5g/litre. Do not use controlled release fertilisers which are unsuitable for spring flowering bulbs in containers due to excessive nutrient release.
Aftercare
In good growing conditions crown imperials will readily form large clumps. If a well-established colony begins to flower poorly then lifting in early autumn when dormant, thoroughly improving the soil and replanting, or moving to a new site may be sufficient to restore satisfactory flowering. The bulbs may take a year or two to re-establish.
Propagation
Cultivar Selection
Fritillaria imperialis 'Aurora': Shorter than most at 60cm (2ft) with orange flowers veined red
F. imperialis 'Maxima Lutea' AGM: Tall, erect stems to 1.2m (48in) with half a dozen or more large nodding, bell-shaped bright yellow flowers
F. imperialis 'William Rex': Intense reddish orange flowers on dark bronze coloured stems to 90cm (3ft)
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Problems
Non-flowering: Most gardeners manage to flower crown imperials in the first year but on less than ideal soils, such as heavy clays or infertile, sandy soils, or where bulbs are planted too shallowly, they rarely flower in subsequent years.
Ensure purchased bulbs are large - at least 8-10cm (3-4in) in diameter - and firm. Always purchase and plant crown imperial bulbs as early as possible in the autumn. It is important they produce strong roots before the onset of winter if they are to flower well.
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