Crocosmia Care Guide: How to Grow Them

Crocosmia Care

Most crocosmias are easy to grow and can tolerate most soils. To flower at their best most will benefit from full sun and a humus rich soil.

Light requirements

As these plants are native to South Africa they do best in full sun. If planted in shade they may put on attractive foliage but fail to flower well, if at all. There are some varieties, such as C. ‘Carmine Brilliant’ that will do well in semi-shade.

Water requirements

Crocosmia is drought tolerant and only really needs watering in exceptionally dry weather. However, the leaves can sometimes become brown if the plant is dry for a long period. In their native South Africa, they are used to hot and dry weather but with periods of summer rain. For this reason, a good summer deluge suits them, and they often flower more prolifically in the weeks and months after a wet spell.

Soil requirements

Your crocosmia will tolerate any soil as long as it is reasonably nutrient rich. They flower reliably even in heavy clay. However, they do prefer a more well-drained soil, so it’s worth adding some sand or grit to heavy soils to improve drainage and reduce the risk of rotting or disease.

Fertiliser requirements

Crocosmia will only need fertilising if the soil is poor. Apply a general all-purpose fertiliser when shoot begin to show in spring. They can benefit from a mulch over winter, especially the less hardy varieties. Container grown varieties will require a general-purpose fertiliser at the beginning of the growing season.

Where to Plant Crocosmia

Plant in a sunny site and they will soon form a clump that produces attractive spikes of leaves and tall flower stems topped with sprays of flowers. The better the position the more abundant and larger your plant will be.

In less ideal conditions they will still do well but may flower less well in heavy soils and when planted in shade.

How to Plant Crocosmia

Crocosmia is a perennial which means it flowers every year and dies back over the winter disappearing completely until new shoots begin to appear once more in spring.

The plants grow from corms, which are similar to bulbs. These can be bought dry or already planted in pots.

Crocosmia look most natural if they are planted in clumps. Planting the corms is similar to planting bulbs. The corm contains all the nutrients for the plant to sprout when the soil begins to warm.

The corms should be planted in spring. Add some well-rotted manure or soil improver if the soil is poor. You can also add grit or sand if the soil is heavy and sticky. Position the corms around 4 to 8 inches (10-20 cms) apart, depending on the size of the variety when mature. They should be planted 3 to 5 inches (7-12 cms) deep with the pointy end up. The corms will produce offsets and spread over time.

If the soil is dry when you plant them water the corms in. They will need to rehydrate before they can begin to grow. Keep the soil moist but do not overwater as this can result in the corms rotting.

If you buy your crocosmia in pots they will often establish more quickly as they have already had a chance to rehydrate.

When growing in containers, select a large pot with plenty of drainage holes. Keep the pot moist, but not waterlogged. Apply an all-purpose fertilizer sparingly for good flower production.

Crocosmia Care

Once planted, crocosmia needs little care and attention. They will benefit from watering when the weather is very dry. They are hardy and do not need to be lifted in winter like more tender plants such as dahlias. They may benefit from a mulch over winter to protect the corms, especially if your garden is in a cold area or they are planted in a very exposed site. Most varieties are very hardy, though.

Some varieties are vigorous and can even be a little invasive, so pull up any that have spread to unwanted areas.

In autumn, when flowering is over, leave the plants until they have begun to die back. Once this happens the foliage can be cut back to ground level.

If you want to cut some flowers for indoors you should choose stems where the lower blooms have just begun to open. They will continue to open indoors. When you first cut the stems place them in a vase of water at 100℉ (37.8℃). Put the vase in a dark place for 48 before using them in your display. This will help the blooms stay fresh for longer.

Plants to Grow With Crocosmia

Crocosmia blends in well with a variety of planting schemes from informal cottage-type gardens to sculptural styles and tropical themes.

Late-flowering shorter orange varieties look great with asters, which also enjoy a sunny site. Other choices include heleniums or late flowering aconitums.

The taller varieties, such as Lucifer, look good planted in swathes interwoven with grasses. Lucifer also contrasts well with deep blue plants such as Nepeta (Catmint) or blue and purple sages.

Later-flowering, fiery varieties can be woven up through purple dahlias to make a vibrant contrast.

In a hot-coloured bed, choose other sunset colours such as the bright red Dahlia ‘Grenadier’ and the bright orange Canna ‘Wyoming’.

Of course, different varieties of crocosmia also look good together. Try pairing the statuesque Lucifer with the dainty ‘Emily McKenzie’ or the bright yellow of Norwich Canary.