Monday, March 3, 2008

Spring Flowering Bulbs

the Fall 1997 newsletter
photo by Powi under Creative Commons license

Autumn is the time to plant spring flowering bulbs, those wonderful harbingers of the return of the warm weather. Bulbs are easy to grow, and with a little preparation and thought are a great addition to the garden. Before elaborating on the planting of bulbs, let’s take a moment to clear up a few misconceptions.

Many people use the term bulb to connote any plant that grows from bulbous underground material. Botanically speaking, some of those plants are tubers, corms, and rhizomes. A bulb is a miniature plant surrounded by scales containing needed nourishment. Examples of bulbs include tulips, daffodils, and hyacinths.

A corm is a solid mass of storage tissue with several growing tips on top. Roots grow out from the edge of a flat, plate-like bottom. Crocus and gladiolus start their lives as corm.

A tuber, like a corm, is a solid mass of storage tissue; however it lacks the plate-like bottom. Both roots and shoots sprout from the growing points called eyes. Potatoes and dahlias are tubers.

A rhizome is a thickened underground stem. Also a storage tissue type with eyes, roots grow from the lower surface, while leaves and flower stalks emerge from the upper side. Irises and cannas are examples of rhizomes.

With that explanation out of the way, let’s return to bulbs. Spring flowering bulbs are planted from September to November. They need about two months of low temperatures for their roots to grow and for proper bud development.

Bulbs are not very demanding, but do require good drainage. As in all gardening, it is a good idea to spend the time preparing the soil prior to planting. Deep digging and additions of copious quantities of organic matter will make for happy bulbs. Bulbs also require adequate amounts of phosphorous and potash for flower and future bulb development, so test your soil and add appropriate organic amendments.

Now that the bed is prepared we come to the hard part – which side goes up. The upper part is usually more pointed than the lower, and small roots are visible at the bottom part. An old rule of thumb says to plant bulbs at a depth of 3 times the height of the bulb. Crocuses are usually planted at a depth of 3” and 3” apart; tulips are planted at 4 to 6” depth and the same distance apart.

Place bulbs at the appropriate depth, nose end up and cover with topsoil. Gently tamp soil to assure good bulb-soil contact. Lay a thick mulch over the bed after the ground is frozen to prevent heaving.

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