When is a Bulb Not a Bulb? - Illinois Farm Bureau Partners When is a Bulb Not a Bulb? - Illinois Farm Bureau Partners

When is a Bulb Not a Bulb?

By  0 Comments


The term “bulb” often refers to any plant utilizing an underground fleshy storage system. Usually perennials, they differentiate into hardy and tender bulbs. The plants all grow and flower, followed by a dormancy period when they die back.

Hardy bulbs tolerate cold temperatures and in some cases require cold storage either underground during winter or in refrigeration. Tender bulbs, unable to survive the cold of our Illinois winters, must be removed from the garden and stored in a more hospitable environment until the soil warms in the spring.

True bulbs come with a complete life cycle in one tightly packed structure that includes roots, stems, leaves and flowers. Most spring bulbs fall into the true bulb category, with summer as the typical dormant period. Autumn rains and cooler temperatures send the signal to start sprouting roots in preparation for active growing in spring. Tulips, daffodils and lilies fit in the true bulb category.

Corms look like flattened bulbs but belong to part of the stem. The base of the stem swells and modifies to contain a mass of storage cells. Each year, the depleted mature corm fades away, replacing itself with one, two or even three new corms. Gladiolus grows from a corm, usually doubling each year. You’ll want to dig them up after the first frost and store them in sawdust or peat moss in a cool, dark place for winter.

See more: Start a Garden in Six Simple Steps

Tubers differ from true bulbs and corms by lacking a basal plant from which the roots develop. Buds, also called eyes, scattered over the tuber’s surface, develop into both shoots and roots. Potatoes and caladiums typify tubers.

Tuberous roots differ from other root structures because the nutrient stores mass in the roots, not an enlarged stem. For a good visual example, look at dahlias or tuberous begonias.

Rhizomes, thick horizontal storage stems, grow parallel to and just under the soil surface. They form branches that send up new shoots away from the mother plant with the potential to become garden thugs. Examples of rhizomes include lilies of the valley, cannas and irises – all efficient spreaders.

Finally, peonies and daylilies comprise a subgroup known as “fleshy roots” because of the nutrient reserves stored in the roots.

Increase your garden by growing one example from each category this year.

See more: 7 Pollinators to Help Your Garden Grow

Ask the Expert

Q: My asparagus bed has clumps of thick woody stumps from last year’s cutting. Should I remove them so they don’t inhibit this year’s spears?

A: No, digging in the bed now can break off or damage the soon-to-emerge spear tips. The circumference of the old stumps seems hard. However, new spears will grow right up through the soft center. You can surface weed to remove winter annuals, but no digging, please.

Leave a Comment

Leave a Reply

Your email address will not be published. Required fields are marked *