How to grow gladioli

How to grow gladioli

Grow gladioli in moist but well-drained soil in full sun. Divide congested clumps every few years.

More on growing gladioli:

• How to plant gladioli corms
• How do I grow perfect gladioli?
• Six best June-flowering bulbs

Where to plant gladioli bulbs

Gladioli originate from hot, dry climates, in South Africa or Mediterranean countries. So they require good drainage and plenty of sun. For best results grow in moist, but well-drained soil, in full sun.

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 15 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 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 propagate gladioli

Over time, clumps of gladioli get 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.

Growing gladioli: problem solving

Sap-sucking gladiolus thrip 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 and aphids and grey mould.

Gladioli varieties to try

• Gladiolus 'Miss Green' - with tall spikes of white-green flowers. Hailing from the Mediterranean region, Gladiolus 'Miss Green' is frost tender
• Gladiolus 'Hastings' - bears 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.
• 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.
• Gladiolus 'Happy Weekend' - produces tall spikes of apricot flowers.
• 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.