Last updated on March 24th, 2022
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Gladiolus is a stunning perennial that is well-known for the tall flower spikes. It gives off a classic look to any garden. What’s more, when you grow Gladiolus you can, of course, cut the Gladioli flowers and add them to beautiful displays within your home.
You can find Gladioli in a variety of colours. No matter the colour they typically grow between 75cm (which is just over 2ft) and 175cm (nearly 6ft) for taller varieties. The taller varieties will need to be staked and are best when placed at the back of your garden borders behind smaller plants, although they grow well in large containers and again, will need staking with canes.
How and When to plant Gladioli
Gladiolus are usually grown from large corms. The best time to plant them is in the spring after any danger of frost is over and your soil is warm.
Plant in full sun in well-drained soil
Before you start planting them in the ground make sure you have the right location. Gladioli prefer full sunlight with well-draining soil. You can prepare your garden by loosening the soil, approximately 30cm deep. Once you have done that, mix a good amount of compost in to help improve the quality of the soil.
Look for bulbs that are around 5cm in diameter. Plant them around 12cm deep and 15cm apart
In order to make sure you get large flowers, you should plant bulbs that are at least 5cm in diameter. When you place them in the ground you want to put them around 12cm deep, with the pointed end facing upwards. After you plant each bulb, cover them with soil and press down firmly, being careful not to firm the soil too much. This alleviates any air pockets in the soil. If you are growing more than one you should space them about 15-20cm apart because they are large flowers and need a little space.
If you want to plant them so that you can cut the flowers in the middle of summer, plant them in rows. This will make it much easier to tend to each plant and subsequently take your cut flowers for indoor displays. If you want to plant them with other flowers in your borders, you should have at least seven in the group to make a real impact and an eye-catching display.
Learn why I use a bulb auger to plant all my bulbs in this guide
Stake once planted so they can be tied to stakes as they grow
Once they are planted, water them thoroughly. Be mindful of colour varieties because you will need to stake them at the time they are planted. Be careful not to damage the bulbs when you set up the stakes in the ground.
It will take about 60 days from the time you plant the bulbs for them to root, grow out of the ground, and produce a good display of flowers but it’s well worth the wait.
Caring for Gladioli
Mulching
Once your Gladioli are planted you can take good care of them by adding a layer of mulch, about 8 cm thick to help retain soil moisture and prevent any weeds from cropping up and stealing vital nutrients out of the soil.
Watering requirements
If you don’t get much rain, be sure to water the Gladioli throughout the summer because they prefer the soil to be kept moist. If you do get ample rain, only water the Gladioli moderately when needed as overwatering can cause the bulbs to rot.
Deadheading and cutting back after flowering
It is important to deadhead throughout the season to ensure a continuous show of flowers and prolong flowering. After you see a faded or dead flower, cut the flowers off and once all flowers on a single stalk are gone, cut the stalk off about 10-20cm above the ground. Remember, just because you have cut away some of the stalks and the flowers do not mean it’s all over for your plant. Leave the plant intact and it will mature and rejuvenate the following season.
Providing winter protection
Add a layer of hay or straw to the ground for extra protection during the winter. If you live in northern England (or higher) and it’s particularly cold in the winter, dig the bulbs out once they have died back and store them in a cool but frost-free place, such as in a shed, until the following spring when they can be planted again.
Pests and Diseases
Gladioli are susceptible to things like bulb rot, grey mould, and other problems that usually relate to inappropriate levels of drainage and root rot. You should also keep a careful eye out for things like spider mites and aphids in spring and over summer which can be sprayed with a pesticide or even soapy water. These can be easily washed off the physical plant with your hose, but be careful not to damage the plants because the weight of the water can cause them to flop over.
Cutting your flowers
You want to cut your recently bloomed Gladiolus flowers for a bouquet or simply display them in a vase in your home, you should cut the stalk off the plant either early in the morning or later in the evening. With a sharp, sterilised knife, cut diagonally through the stalk and place all of your recently cut stalks into a vase or bucket with lukewarm water.
Be careful to leave at least four leaves on the plant if you want to be able to reuse the Gladioli bulbs. Try to cut stalks that have only one or two open flowers. If you go for a stalk whose flowers are almost all open, you won’t have anything to look forward to when you put the flowers in your vase or add them to a bouquet. If you pick a stalk with mostly buds, you can look forward to all those buds opening into stunning flowers.
Every few days that you have your cut flowers you should remove 3cm off the bottom to help keep them looking fresh and they tend to last longer too if you do this, although not everyone does.
Overwintering Gladioli bulbs in winter
If you live in a particularly cold area you will need to dig up the bulbs after the foliage has faded and they have died back, this process is essential because it put goodness back into the corms, which they will need the following spring. Make sure you dig up the bulbs before the first frost.
- To do this, use a spade and remove the entire plant. Be careful to avoid injuring the bulbs while doing so.
- Discard any damaged bulbs and shake loose away any soil.
- Cut the stalks back to within 3cm above the bulb.
- Place the bulbs in the sun to dry for at least one or two days if your weather permits.
- Place them in a wooden crate or tray and leave them in a warm, well-circulated area for 2 weeks where the temperatures remain between 27°C and 29°C.
- Dust each with a fungicide (such as copper sulphate) and place them in a paper bag.
- Store the paper bags or other cloth bags in an area with low humidity where temperatures range between 2°C and 7°C like in a cold cupboard or shed. Do not allow them to freeze. An ideal location is a cool basement or cupboard.
You can then replant them in the spring using the same method you did the first time you planted them.
Image credits – Shutterstock.com
