Skip to content A popular choice in gardens because of its elegant reddish-orange flowers, this is an invasive species that can spread rapidly if not controlled. Montbretia propagates through a network of underground corms and tends to spread via these rather than through seed dispersal
Montbretia crocosmia x crocosmiiflora was first bred in the 1880s and came to the UK via France, although its origin is distinctly South African. It has been a popular plant in gardens for most of that time and is more common in western parts of England, Wales and Scotland.
It’s different from many other plants in that it has corms which are fleshy underground parts of the stem. These corms act as a storage organ for the plant, but they can also initiate growth in much the same way as a bulb. The corms of the Montbretia plant can grow quite deep which makes fully eradicating it problematic.
While it is an attractive plant, it is now listed in Schedule 9 of the Wildlife and Countryside Act 1981 as invasive although it is not illegal to have Montbretia on your property, Whether you do or not, you must pay special attention to how you dispose of cuttings and corms if you want to get rid of them.
The soil and plant matter are considered controlled waste so have to be handled by a licensed garden waste company. While Crocosmia x crocosmiiflora is on the invasive plant list, other Montbretia varieties are still available online and in garden centres around the UK. It tends to prefer moist, well drained conditions but can lay dormant underground during dry periods.
The plant dies down in the winter and the corms become dormant but during the spring you will begin to see the familiar sword-shaped leaves appearing once more. The Crocosmia x crocosmiiflora variety is distinctive for its exotic and decorative gladioli-type flowers that provide a burst of exotic colour.
The plants tend to flower during the late summer and into the autumn. Even though they are an invasive species, people often like to have Montbretia in their gardens because the flowers can bloom for several months before the colder weather starts to settle in.
The flowers are two-toned bright orange/red and tubular with six petals that are fused and are around 4 cm in length. Unlike other plants, these don’t then turn into seeds in most cases. When they do they form from small green, brown fruits that can be eaten by birds and dispersed.
Montbretia leaves are long and narrow and usually emerge from the base of the plant. There can be between 6 and 12 leaves for each corm, and they grow to around 60 centimetres. In between the leaves, you will see upright, rounded green stems from which the flowers will eventually develop.
There are over 400 different varieties of Crocosmia available, and most have been purposely bred for the garden. These include:
As a colourful garden variety, there’s a lot to be said for Montbretia – it’s not only attractive but takes little in the way of maintenance. When allowed to spread, however, it can quickly overwhelm other species and local flora and fauna which is why it’s such a problem in the wild.
While it is still popular in gardens, in more recent years Montbretia has spread to the countryside where it is causing problems with roadsides, waste ground and hedge banks, especially when garden trimmings are dumped. Under the Wildlife and Countryside Act, it is illegal to cause the plant to grow in the wild.
Montbretia loves sunny, well drained soils, but does not need a rich soil to thrive, so once released into the countryside it can quickly grow out of control. Once clusters get a hold, they can easily outcompete other flora which is likely to have a significant impact on the local ecosystems.
While it’s not against the law to have Montbretia growing in the garden, it is a good idea to ensure that the plant does not spread to other gardens in the area. Some councils will have their own rules and regulations concerning invasive species like Montbretia and it may be prudent to check if you need to remove the plant.
It’s important to check the plant is not spreading beyond the boundaries of your garden and you may want to remove some of the corms when it dies down in the winter to prevent them from getting out of control. Again, disposing of the plant and any cuttings needs to be done responsibly and certainly, any roots or corms should go to a licenced landfill site.
Rest assured, where invasive species are identified at an early stage and tackled correctly, problems can usually be avoided. Our specialist consultants complete thorough surveys to identify the extent of the problem. Our plans aren’t one-size-fits-all; they’re customised to tackle the invasive species at your property effectively, taking account of all of your requirements.
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