Gladioli, or the ‘Sword Lily’ is a striking and towering flower worth growing in your garden that add spectacular height and colour to your garden. Find out the answers to Google’s most asked questions about this flower in my video, and in the blog below.

Where are Gladioli native to?

Gladioli are native to Africa and the Mediterranean area. There are reportedly 300 species of these flowering plants, all in the Iris family. They are also found growing natively in Madagascar!

Wild Gladioli in the Mediterranean

Where do Gladioli grow best?

Gladioli originate from a warmer climate than the UK has, so find somewhere with good drainage and full sun.

Do they self-seed?

Some perennial varieties may self-seed, but likely only the hardier varieties if the seedlings were to survive the winter.

How do you grow Gladioli from seed?

You can grow Gladioli from seed, but you will need to be patient. After sowing your seeds, the corms will reach flowering size within 2-3 years.

Sow them in peat-free compost in a cool greenhouse if you have one, in February. However, most gardeners choose to grow their gladioli from corms, as this is much quicker. These are easily accessible in shops.

Gladioli flower head with seeds developing

How do you grow Gladioli?

Plant your corms in a sunny spot with good drainage. Plant them in spring, and you don’t need to soak them first.

The very latest you can plant them is in July, otherwise they won’t flower in time before the frost returns in autumn. I got mine from the discount section of the supermarket and brought them up to full health.

Plant them 10-15cm deep (4-6 inches). Try to space them about the same distance apart if you can.

When growing them in the ground, water them regularly if there are periods of dry weather. If you are growing them in containers, make sure that the compost remains damp, not soaked, whilst the gladioli are growing.

Do Gladioli need deadheading?

No, gladioli don’t need to be deadheaded. They won’t flower more than once per year, so don’t need to be deadheaded to encourage more blooming.

Wait for the foliage to fade, rather than cutting the plant down after fading. This gives the corm more chance to prepare for the winter months.

Do they flower in the first year?

When planted from corms, yes, your gladioli will flower the first year. If you grow from seed, you will be waiting between 2 and 3 years to enjoy the flowers.

Flowering gladioli in pink

How long do Gladioli flower for?

Gladioli flowers bloom for a short time, up to 3 weeks if you’re lucky. To ensure your gladioli display lasts, plant them successionally through the spring and mid-summer. This will make sure they flower regularly throughout the summer period.

When do Gladioli flower?

You can anticipate your gladioli to flower between 10 and 14 weeks after first planting your corms.

Are they good for bees?

Yes, bees, bumblebees and other pollinators like butterflies all enjoy gladioli!

Gladioli with a bee inside

Are they annuals, biennials or perennials?

Gladioli are tender perennials, that form clumps. This means that if they are protected from the frosts during winter, they will return each year.

How big do Gladioli grow?

The tallest you can expect most Gladioli to grow to, is approximately 1.2 metres (4 feet) tall.

Do Gladioli need staking?

Generally, gladioli don’t need staking. This will guarantee that the blooms won’t fall over, but it is unlikely.

You will typically only see gladioli staked for competitions.

Gladioli staked

Do Gladioli need feeding?

If you are growing your gladioli in poorer soil, then a rich liquid fertiliser like tomato feed is quite beneficial for the plant. This will promote flowering when the spikes start to appear.

How long do they live for?

Gladioli can live for many years, provided they have good protection from the cold weather.

If you live somewhere prone to severe or long periods of frost, it may be worth lifting the corms in the autumn/winter to give them a better chance of growing back well each year.

What do you plant with Gladioli?

Gladioli grow well with Begonias and Lilies. They all have similar growing conditions, and grow to different heights, meaning they combine well as a garden border, with the gladioli and lilies at the back of your border.

They also grow well with Dahlias and Zinnias, requiring similar conditions, and all have a great variety of flower shades that you can match and curate a design with.

Begonias in many colours
Bright and colourful zinnias

When do you divide Gladioli?

Once you replant your corms, they will start to grow back as the soil warms in March or April.

If you have hardier varieties that you have left in the ground, you can expect them to grow back at around the same time.

When do they start to grow back?

Wildlife are particularly fond of Sweetcorn when they are seedlings. Slugs and snails are partial to a snack on your young Sweetcorn plants.

As the corn matures, birds, mice, and squirrels make a good meal out of them.

There are a few natural deterrents for slugs and snails that you can try. Dried-up, ground eggshells can create a sharp border around your individual plants that they may find difficult to travel over.

Additionally, you can create a garlic drench with two crushed garlic cloves and two pints of water. Boil the mixture for thirty minutes, then strain the liquid off. An old plastic milk bottle makes a good container to drench the area you are protecting.

Also, if your standard corn cross-pollinates with a ‘supersweet’ variety, or vice versa, the resulting kernels can have poor flavour. To avoid this, grow your ‘supersweet’ and standard varieties separately.

Will Gladioli spread?

Yes, gladioli can spread. The corms will multiply underground every year. If they are hardy and you leave them in the ground over the winter, you may well see more of them the following year.

Otherwise, if you lift them every autumn, it is up to you how many of them you choose to replant the following year.

Gladioli corms

Are Gladioli frost hardy?

Most varieties of gladioli are not frost hardy. This is why many gardeners will lift the corms and store them away during the winter.

What are their common problems?

Aside from not being huge fans of extremely wet and cold weather, gladioli are generally trouble-free besides pest damage.

You may find that your corms rot when stored for winter – called Gladiolus corm rot. This is caused by Fusarium rot, causing the leaves to grow weak and yellow. Many varieties of gladioli are resistant to this, but none are immune.

Get rid of any infected corms when lifted in the autumn and inspect any remaining before planting in spring. They may have discolouration and dark bundles on the outside.

What are the common pests of Gladioli?

Aphids, slugs and gladioli thrips are the most common pests that affect gladioli.

If you can tolerate aphids on your gladioli, do so. Otherwise, encourage natural predators like ladybirds, ground beetles, parasitoid wasps and earwigs into your garden.

Gladioli thrips can cause the foliage and flowers to become mottled, and in severe cases cause the flowers to fail to open.

Tolerate them if you can. Encourage any natural enemies of thrips into the garden, and one that can occur naturally is Orius laevitagus. You can also cut down any affected growth from impacted plants before storing the corms, as this will discourage overwintering thrips from causing a problem the following year.

Thrip pests

Are Gladioli poisonous to humans?

Yes, gladioli is poisonous to dogs and cats. Try growing them in containers that are out of reach if your pet is likely to try to nibble on your gladioli plants.

Eating the plant itself may cause vomiting, stomach upsets, and lethargy if consumed by dogs. But it is the corm you want to ensure they don’t try to eat, as this is the most toxic part.

Are Gladioli poisonous to pets?

Sweetcorn is safe for your pets to eat. It is quite a healthy addition to a dog’s diet, in moderation. As it contains quite a large amount of sugar and carbohydrates, make sure not to give too much to your furry friends.

You may find that corn is present in a lot of cat and dog foods that you already give them.

Sweetcorn are delicious and towering vegetables that are well worth growing in your garden. If you have any questions about this or any other plant you want me to do a video on, please subscribe to my YouTube channel and leave a comment below one of my Google Questions videos.

Find out my answers to Google’s most asked questions about Agapanthus:

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