How to grow gladioli

When to plant gladioli bulbs

Plant gladioli bulbs in spring - there's no need to soak them beforehand. You can plant in pots from March as long as you keep them in a frost-free spot such as a greenhouse, or directly into the ground from May. The latest you can plant gladioli bulbs is July – any later than that and they won't flower in time before the frosts come. If you're planning to use them for successional colour, plant a handful a week or so apart from March onwards, to extend the display. Those planted in pots can simply be plunged into borders as they come into flower.

Plant 15cm deep in moist but well-drained soil. On heavier soils, add a generous handful of horticultural grit to the planting hole, to aid drainage.

Here, Monty Don demonstrates how to plant gladioli bulbs in a pot, to plant into the garden later:

How to care for gladioli

Water well during the growing season and stake plants before the flower spike emerges. While in flower, give your gladioli a tomato feed or comfrey feed every couple of weeks. For tender varieties, and in colder parts of the country, lift the corms each autumn and overwinter them in frost-free conditions. For hardier varieties, cover with a thick mulch in autumn to protect from cold snaps. Divide congested clumps every few years.

Find out how to give gladioli the best possible growing conditions, in our Quick Tips video with Lucy Hall:

How to cut gladioli for flower arrangements

If you're growing gladioli for cut flowers, plant a few corms every fortnight from May to July to ensure a steady supply of flowers. Cut flower spikes in the morning when the first flower or two are just beginning to open, and place in water immediately. Leave as much foliage behind as possible so that plants can photosynthesise and grow well next year.

How to propagate gladioli

Over time, clumps of gladioli become congested, resulting in weaker plants with few or no flowers. To prevent this, divide clumps every few years in autumn, selecting the best new corms for replanting the following spring.

Can I leave gladioli bulbs in the ground?

The traditional method of growing gladioli in the UK is to dig up the corms in autumn to overwinter indoors. However, with climate change, winters are currently milder than previously, and you may get away with leaving them in the ground, particularly if you live in the south. If you're prepared to risk losing your gladioli bulbs, cut back old stems and apply a thick mulch over the area in autumn. Alternatively, lift them and dry them before storing in trays in a frost-free spot for winter.

Pests and diseases

Sap-sucking gladiolus thrips can attack plants, causing white flecks to appear and sometimes flower buds will go brown and drop off. Prevent the spread of thrips by removing affected foliage and flowers. Gladioli can also fall prey to slugs, aphids and grey mould.

Gladioli varieties to try

• Gladiolus 'Miss Green' – tall spikes of white-green flowers. Hailing from the Mediterranean region, Gladiolus 'Miss Green' is frost tender. Height x Spread: 90cm x 10cm
• Gladiolus 'Hastings' – tall spikes of orange/brown flowers. In warmer regions it may survive outdoors all year round, particularly if the corms are given a thick mulch in autumn. However in colder regions it's best to lift the corms each autumn to overwinter in frost-free conditions. H x S: 70cm x 10cm
• Gladiolus nanus 'Charm' – one of the hardier gladioli, this has masses of violet pink flowers enhanced by a pale white blotch at the lower lip of the flower. H x S: 70cm x 10cm
• Gladiolus 'Happy Weekend' – tall spikes of apricot flowers. H x S: 90cm x 10cm
• Gladiolus colvillei 'The Bride' – a fantastic gladiolus, bearing pretty, delicate white blooms from late-spring to mid-summer. Plant bulbs in autumn rather than spring. Not fully hardy. H x S: 60cm x 15cm
• Gladiolus communis subsp. byzantinus – this early-flowering gladiolus has vibrant magenta pink spikes of flower from late spring until early summer. H x S: 90cm x 10cm
• Gladiolus murielae – also known as Acidanthera murielae, the Abyssinian gladiolus has fragrant white flowers with deep maroon centres from August to October. H x S: 90cm x 10cm