This may be so, but don’t mess with your Montbretia. Not just yet, anyway. If the leaves are still green, they are still photosynthesising - using the remaining autumnal sunlight to create sugars. These sugars are then laid down in the corms (bulbs) to enable the plant to perennate through the winter before putting on new growth in spring. Remove any spent flower stems at the base, but resist the temptation to remove and tidy up the foliage until it has turned brown.
Don’t remove Montbretia foliage until it turns brown
Montbretia is the common name for the hybrid Crocosmia x crocosmiiflora, created by a French plant breeder in 1879. However, it actually grows extremely fast and clumps quickly get congested, leading to reduced flowering. Much Montbretia has naturalised itself in the wild, and since 2010, it has been illegal to plant or let it grow in the wild.
There are still plenty of Crocosmia cultivars that are not so rampant, and they make a valuable component to late summer and autumn flowering borders. They are usefully unfussy about what type of soil they grow in, and are tolerant of partial shade (although flower best in full sun). Cultivars of Crocosmia pottsii and C. masoniorum are also tolerant of damp soil.
Suggested Crocosmia cultivars and planting ideas
A century of hybridisation has generated a range of heights and a whole palette of colours from the ‘hot’ end of the spectrum. Large cultivars for positioning at the back of the border include Crocosmia ‘Zeal Giant’ or the more well-known C. ‘Lucifer’. Plant tall cultivars deeply to prevent them leaning over, and give them plenty of space.
For autumn flowering borders, three later-flowering cultivars include Crocosmia x crocosmiiflora ‘Saracen’, with its bronze leaves, and red and purply-black flowers; the orange C. ‘Star of the East’, and C. x crocosmiiflora ‘Plaisir’. These grow to a height of around 50cm and would all work well alongside asters and rudbeckias in a border for late-season interest.
If you have a specific colour scheme in mind, the cultivar with the reddest hue is C. ‘Hellfire’. More pinkish varieties include C. ‘Raspberry Spray or C. ‘Culzean Pink’. For yellow flowers, there’s C. ‘Twighlight Fairy Gold’ and C. ‘Paul’s Best Yellow’.
Key care tips
· Water well in summer;
· Remove spent flower spikes, before the plant expends its energy forming seeds;
· Remove foliage once brown – probably after first frosts;
· Protect any grown in containers from frost;
· Divide clumps every three or four years, in early spring, before growth starts. Discard up to half to three-quarters of the old corms and replant the fattest.
Crocosmia in a border of Agapanthus at Hydrock Hall, Cornwall, August 2019.