Even if they have similar characteristics, calling them or knowing them all as bulbs is not correct. Let’s see why it is important to know what differentiates them.

With the term bulb, we often enclose all species of flowering plants or horticultural, which have an underground organ that has the function of enclosing all the nutrients and energies for development, growth and a new life cycle every year.

So we enclose all plant species that include: bulbs, rhizomes, corms, tubers and tuberous roots.

This is not so correct, because although they have similar characteristics, they need different methods of cultivation, reproduction and care.

So you love planting bulbs? Have you been growing them for years without ever having studied this subject in depth?

Although the right term to use should be GEOFITE, following this article I will try to explain what are these differences and the information we need to know.


Imagine now to take a healthy onion and start peeling it. Do you have in mind what it is made of? Well the onion is a bulb and they are made just like that!

The bulbs have a round shape, narrow at the top, widens in the middle and even narrower at the bottom, where we find the so-called walker. Here are the roots.

The common feature of all bulbs is that they have a tunic on the outside that covers the scales, the latter are fleshy leaves that protect the embryo of the flower. You should know that each year the bulb forms new scales, which can be taken and planted individually to reproduce and then multiply the species.


The corms are similar to the bulbs, they tend to always have an oval shape. These, however, are not formed by scales or fleshy leaves, but have a unique root, white and compact, always wrapped in a protective outer tunic. The corms are modified stems that store all the necessary nutrients.

The reproduction of the corms takes place through the progeny corms, they come to life over and attached to the mother corm, which dies by the end of the vegetative cycle of the plant.


Rhizomes are stems that have the characteristic of growing horizontally, just below ground. The roots form in the lower part of the rhizome, while the stems develop in the upper part.

The rhizomes expand as the plant grows. From these, new nuclei develop which will give rise to new stems and therefore to other plants. These new nuclei can be subdivided to reproduce the species. The part of the rhizome furthest from the plant will be the oldest and therefore die. A rhizomatous plant is Curcuma, from which the delicious spice is obtained. Read more here: Cultivate turmeric and obtain its spice.


The tubers are underground stems, enlarged and irregularly shaped, so they do not have a flat base. The potato is the perfect example of an edible tuber. As we can see from the potato itself, the tubers have no tunics, but are protected by an outer skin.

On the upper base of the tuber, more growth nuclei come to life, where the stems and therefore the plants will develop. Many tubers grow larger as the plant grows, but do not renew, will reach a maximum size and will stop growing.

Tuberous Roots

They are real swollen roots that store all the nutrients useful for growth. In the upper part there is the so-called crown, it is the part where the stem will come to life. From here, portions of tuberous roots will be propagated.

On the crown, as new buds develop, they will give life to new stems and therefore to new seedlings. To propagate a plant with tuberous roots, you will need a portion of them that already have a crown, where at least one bud will come to life.

A single root will not be able to develop a plant.