Flower Bulbs

It's true, flower bulbs are not necessarily true bulbs. For simplicity sake, corms, tubers, rhizomes and true bulbs are typically referred to as bulbs.

True flower bulbs are an encased leaf bud, or flower bud surrounded by fleshy layers or scales fastened upon a fibrous base from which roots are produced.

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True Bulbs

The onion is the most widely known true bulb. It is made up of layers. Hyacinths and tulips are also layered, making them true bulbs.

Lilies are made up of overlapping scales. Lilies are also true bulbs even though they aren't wrapped in layers the way an onion is.

This picture on the left while not as clear and detailed as I'd like, shows the inside of a true bulb. You can see the layers that make up parts of the bulb.

After cutting away more of the layers this picture on the right shows what the bulb looks like up close.

If you look closely you can see the fibrous base from which the roots are produced. It's the pale yellowing area near the bottom center of the bulb.

Don't cut your own flower bulbs in half though or you'll ruin them.
This one was damaged by my garden fork when I was digging up a group of bulbs that needed to be split.
Rather than just tossing it onto the compost pile, it seemed like a perfect sample to take pictures of.

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Corms

A corm is a compressed stem typically having a little node at the top. It is a solid object and quiet hard rather than fleshy like true bulbs.

Galdiolus and crocus are the most widely known corms.

Corms are good for one year. The original corm will wither and die but is replaced by a new corm that forms usually on top of or beneath the original corm.

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Tubers

Tubers are short, fleshy, swollen roots that typically grow underground.

Dahlia and Sweet Potato are two widely known tubers.

The foliage and flowers sprout from the neck of the tuber. The function of the tubers is to serve as food holding tanks upon which new shoots can survive until their own rooting system is able to provide it.

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Rhizomes

Rhizomes are thick fleshy rootstock that grow horizontally near the surface of the soil.

The German Iris and Ginger are two widely known rhizomes.

The bottom of a rhizome shows holes where roots were growing or going to grow. The orange colored arrows point to some of the root holes.

You'll want to inspect your iris rhizomes every few years to make sure borers (hungry worm like pests) haven't invaded your rhizomes. You'll be able to tell when you have them because the holes will be much bigger than root holes and the rhizome will have a soft squishy feeling.

If you note borers in your rhizomes, you can get rid of them by soaking the rhizomes for an hour or two in a gallon of water in which a cup of bleach has been added.

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Why Grow True Bulbs?

The main advantage of growing true flower bulbs is that their flower buds are actually encased within the bulb at the time of planting and they are surrounded with a stored up food supply. You can plant them and leave them alone and they'll flower nicely.

More About Bulbs

Garden Bulbs
Bulb Care
Bulb Food
Deer Resistant Bulbs
Spring Bulbs
Summer Bulbs
Fall Bulbs
Storing Bulbs
Buying Flower Bulbs
Planting Bulbs
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