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.
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 corns, 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 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 left with Stipa grass.
Good varieties of Crocosmia to grow
The Crocosmia listed below are all fully hardy and so you can plant and leave them in the borders over winter. C.Lucifer illustrated above, 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 varieties but check the label as not all are fully hardy which is not surprising bearing in mind they originate from South Africa. C.Lucifer was developed in the 1960s by Alan Bloom of Bressingham who was so prominent in the plant world. He also
developed `Bressingham Blaze', a fine red, and `Spitfire', an orange-red, the shorter `Vulcan' a bright red and `Emberglow' a paler orange. All Crocosmia are in shades of red, yellow orange and some blend the two, such as 'Jackanapes' which is a short very attractive bicoloured variety of red, orange and yellow blooms but unfortunately not fully hardy, only ** although suitable for sheltered gardens.
In 2017 C. 'Severn Sunrise' (illustrated left) was awarded the RHS Award of Garden Merit and is a lovely soft orange tinged pink variety reaching between .5 -1m (20-40"). It is hardy to around -15 H5 and in colder parts it will benefit from a winter mulch.