How to grow Crocosmia
Crocosmia is easy to grow and maintenance free, flowering from mid to late summer in strong shades of red, orange and yellow. It is very reliable, a great border plant with lovely bold flowers in strong colours. It is a herbaceous, which means it flowers every year and dies back over the winter to bare earth, regrowing each spring. Crocosmia forms clumps with attractive sword shaped leaves and is long flowering. Although one of the most common varieties, Crocosmia Lucifer is tall, up to a metre, other varies are more suitable for middle of the border being around 60-80cms, so you need to select the variety carefully to make sure it is the correct height for where you want to plant it. Crocosmia makes a great addition to the border, being very easy to grow, possibly too easy as some varieties are vigorous, if not invasive, but to check growth just pull up and remove any unwanted spread.
Crocosmia Lucifer, illustrated in the middle 2nd image, looks magnificent, and is a tall architectural plant, with strong red flowers. Crocosmia 'lucifer' is also illustrated below which shows that although tall it does not require staking, which is an added bonus. Crocosmia originates from South Africa flowering in all the sunrise colours with much variation in height; smallest varieties such as Jackanapes, and Canary Bird can be as small as 60cms (24") compared with Lucifer and Columbus 120 cms (48") and height is a factor as to where plants are placed in the border. Also some specialist varieties, often seen at plant fairs and shows are very attractive but unfortunately not all are fully hardy. (explanation of frost hardy) Crocosmia make great cut flowers and as the clumps produce so many blooms there are plenty for the garden and the vase.
How to Plant Crocosmia
Crocosmia will tolerate a wide range of conditions with a strong preference for a spot which is not too dry with plenty of sun. If the site is too dry flowering will be reduced. Crocosmia are reliable border plants and the cheapest way to cultivate is from corms, rather than plants. They grow easily from corns and flower reliably.
The Crocosmia corms, which are similar to bulbs, need to be planted in early spring so they hydrate before starting to grow which they will do when the soil warms up in early Spring. Plant Crocosmia corms about 8-10 cms (3-4") deep below soil level in a group to form a clump. Crocosmia are trouble free and provide excellent late colour to the borders. Crocosmia were formerly known as Montbretia and may occasionally still be referred to by this name.
Crocosmia look good planted with grasses, especially C. Lucifer with the taller grasses, illustrated above right with Stipa grass.
Good varieties of Crocosmia to grow
Many Crocosmia listed here are fully hardy, and so you can plant and leave them in the borders over winter. C.Lucifer illustrated above left and right, C. masoniorum 'Rowallane Yellow' is as the name suggests a lovely yellow variety up to 80cms; are both good and have the RHS award of garden merit. There are many other good varieties, but it's best to check the label as not all Crocosmia are fully hardy, which is not surprising bearing in mind they originate from South Africa.
C.Lucifer a very tall striking variety growing up to .8m ( above right) and was developed in the 1960s by Alan Bloom of Bressingham who was so prominent in the plant world. He also developed C. `Bressingham Blaze', a fine red, and C.`Spitfire', an orange-red, the shorter C.`Vulcan' a bright red and C.`Emberglow' a paler orange.
All Crocosmia bloom in shades of red, yellow, orange and some blend the two, such as 'Jackanapes' . Most Crocosmia are fully hardy but not all, such as Jackanapes so it is worth checking first especially if your garden is more exposed. Crocosmia have a preference for a sunny spot, but are tolerant of a range of conditions including heavier wetter soils. They may flower less well in less ideal conditions.
C. 'Severn Sunrise'
In 2017 C. 'Severn Sunrise' was awarded the RHS Award of Garden Merit. It has flowers which are a lovely soft orange, tinged with peach growing up to between .5 -1m (20-40"). It is hardy to around -15 H5 and in the colder parts of the country it will benefit from a winter mulch.
C. 'Carmine Brilliant'
This is Crocosmia 'Carmine Brilliant' a lovely soft pink and yellow variety growing up to around 60cms. A good all rounder, not fussy about soil type, growing in sun or partial shade, sheltered or exposed spot with the RHS award of garden merit.
Another Crocosmia which is very easy to grow and tolerant of most conditions. It is an attractive bi coloured variety growing up to between .5 and 1 meter. It is quite hardy but not fully, H5 so will benefit from a sheltered spot or mulch in exposed areas.
C. Norwich Canary
A bright yellow variety not often found but a variety bred from it C 'George Davison' is much more common and is very similar, also yellow, a shorter variety growing up to 40cms.
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