Is It Too Late To Plant Gladiolus Bulbs?

By Paul Smart •  Updated: 09/21/21 •  3 min read

Is It Too Late To Plant Gladiolus Bulbs? Gladiolus is one of the most popular spring-planted bulbs that generally produces flowers in mid to late summer. Most gardeners plant the bulbs (corms) in mid-spring, but what happens if you miss the planting window? How late is too late to plant them?

Gladiolus need to be planted at least 4 months prior to the first frost of the season to ensure that they have a realistic chance to flower. This means that for most regions early to mid-summer is about the latest you could plant them, however, this will vary from region to region based on the specific climatic conditions.

Gladiolus typically take about 90 to 100 days from planting to produce a flower, and the period of blooming can last up to 2 months, or until the first frost arrives. However, for the plant to actively grow it requires temperatures of at least 50°F (10°C) so if you live in a region where the average daytime temperatures are relatively low it may be necessary to plant them even earlier.

This advice applies to sub-tropic, temperate, and cold temperature areas. If you live in an area that is frost-free year round, such as the tropics, you can pretty much plant Gladiolus at any stage during the year.

How To Plant Gladiolus

Gladiolus corms are readily available from your local garden center or they can be purchased online from Amazon and delivered within a few days. Once they arrive the Gladiolus corms should be planted at a depth of 4 inches (10cm) with the pointy end facing upward.

When planting them in the garden they should be spaced around 4 to 6 inches apart in a warm sunny location. In terms of soil conditions, they will tolerate a wide range of different soils but prefer rich, moist soil with good drainage and plenty of nutrients. Ideally, it is best if the soil is slightly acidic, and the soil conditions are not too wet.

Additionally, it is best to aviod areas that are exposed to strong winds as the tall flowering stems can be damaged relatively easily. If the plants are in a windy location it is likely that you will need to stake the plants.

To ensure that the plant performs at its best is advisable to apply manure pallets on the surface of the ground after planting. Regular watering of the area will ensure that the plant receives nutrients on a regular basis.

Extending Cut-Flower Life Of Gladiolus

If you are planting the Gladiolus later in the growing season it is best to use them as cut flowers in the house as this will extend the period you get to enjoy them, particularly if the weather is starting to close in.

To maximize how long the flowers last once cut, it is best to bring them inside in the late afternoon or evening. Once the flowers are inside trim the base of the stem at a 45-degree angle to maximize the surface area. This will ensure that the plant is able to more easily absorb the water. Additionally, it is important to ensure that any leaves that are going to be below the waterline are removed.

Once the flowers have been placed in water in a vase it is important to select a location that does not get too hot as this will increase the speed that the flowers dry out. It is also important to replace the water once a very few days to avoid a build-up of bacteria in the water.

Paul Smart