How to grow gladioli
Find out all you need to know about growing gladioli, in this detailed Grow Guide.
Gladioli are often known as sword lilies due to their long, pointed leaves. The distinctive tall flower spikes emerge in summer and come in a whole host of colours. Although they have suffered from an unfashionable reputation, despite being popular props for musicians and performers, they are sneaking back into favour. It's not hard to figure out why, as they're perfect for bringing colour to a sunny herbaceous border, providing good contrast with grasses and other flowering plants. They also look good in containers and make excellent cut flowers.
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:
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.
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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.
Advice on buying gladioli
- Gladioli come in a vareity of heights and colours, make sure you choose the right ones for you
- Gladioli do best in a moist but well-drained soil and often need staking
- Always check bulbs and corms for signs of mould and discard any affected ones before planting
Where to buy gladioli
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.