Bernardi Garden Supply • Gladiolus

Growing Gladiolus – The bulb

Gladiolus bulbs are more properly termed corms. The difference - bulbs are made up of layers of modified leaves, while corms are actually plant stems. On top of a corm exist small buds that will in turn grow shoots that produce leaves and the plant itself, while also throwing roots below. The corm of the gladiolus is quite round and resembles a bulb, hence the misnomer. It is from the corm that the actual plant and its root originates so it is important that the corm be undamaged when you buy it and handled with the care. Healthy gladiolus have a smooth outer covering called a husk, and should be firm and not discoloured in any way. The corm contains a store of nutrition in order to start growing - all one has to do is plant it in adequate soil and provide water. The corm can also be used for propagation, but more about at the bottom of this page.

Growing Gladiolus – Planting

The gladiolus is not a very fussy plant but prefers a well drained soil that has been mixed with a little enhanced soil or black earth, natural fertilizer or, if possible, autumn leaves so it has a lot of nutrition to use. To be a bit more specific the soil should neither be acidic or non-acidic - a pH-level around seven is optimal for the gladiolus bulb. Soil testing should tell you what amendments you need to make (if any) to optimize your gladiolus planting bed. Once the soil has been prepared, you can plant approximately two or even three weeks before the frost free date in your zone and the gladiolus will flower 8 to 10 weeks after planting. To enjoy flowers throughout the summer you can stagger your plantings for every two weeks until the middle of summer, perhaps 'til the end of June/early July. This should take flowering into early fall while the temperature will stay above freezing in the evenings. For optimal growth, feed the corms at planting time with a high phosphorous fertilizer and again with a high nitrogen fertilizer 7-8 weeks after planting. The corms are best planted around four inches under the surface with their growing parts pointing upwards and no closer than six inches from each other. Once in the ground the planting site need to be richly watered so that the bulbs can get established nicely. This will promise for an attractive, well-covering flowerbed to enjoy throughout the summer and fall.

Growing Gladiolus – Getting new corms

In areas where the gladiolus does not need to be lifted before frost, the gladiolus corm will readily create new corms around it - this is a natural way for the gladiolus to spread and can be used to great effect in the garden. If you do not want the gladiolus to spread and take over the entire garden, it would be beneficial to dig up the surrounding corms every other year and distribute them to friends with gardens, or use them to start a new bed. In temperate climates, however, the gladiolus corm will need to be lifted before winter, and therefore cannot self-propagate. So how do you get new corms? When you dig up the corms after the first frost has killed off the foliage, you will see tiny little corms on the bottoms of the main corm. These are called cormels and these can be separated from the main corm and stored over the winter as well. These cormels can be planted in the garden the following spring and allowed to mature into a full corm over the growing season. Cormels will likely only throw up a stalk and leaf, not flowering until the second year of planting. The idea is to dig these up as well in the fall and the second season they are planted, you will obtain a mature plant.