It’s Bulb Planting Time

I love fall. It is usually when I rescue my garden from the weeds, which established themselves when the summer heat was too oppressive for me to get down and dirty. The prospect of gardening in mild temperature is a definite motivator, combined with the fact that this is one of the best times to install new plants in the garden.

This is also a great time of year to plant spring flowering bulbs. They can easily be combined with winter annuals and spring flowering perennials to add color and extend your garden bloom.  Generally, spring flowering bulbs need full sun for six or more hours, good soil drainage, and low competition of roots from trees and shrubs. There are a few expectations; the world of bulbs is vast.

Yarrow and Allium-by Michelle Wallace

Bulbs are a form of plants referred to as geophytes. This term comes from Greek meaning “earth plant.” It refers to an assortment of underground storage structures that include bulbs, corms, tubers, tuberous root, tuberous stems, and rhizomes. Some are hardy and will survive the cold winter temperatures, while others are tender and must be replanted each spring.

Since bulbs store their own energy, the first year after planting you are guaranteed performance.  However, continued performance will depend on the how the bulbs were planted and the type of care they receive. Bulbs like well-drained soil – preferably a sandy loam. Most of the triangle has clay soils with poor drainage. To improve the drainage of clay soils a generous amount of compost must be added. Spread a four-inch layer of compost over the planting area then till it into the top 12 inches of soil. If the soil has poor drainage, you may want to consider planting the bulbs in a raised bed or installing a drain tile under the bed to remove excess water.

Bone meal with a low nitrogen and high phosphorus ratio of 1:3:2 is an excellent organic fertilizer for bulbs. We always recommend soil testing first prior to adding fertilizer. The ideal pH for bulbs is 6.5 to 7.2. A soil test will also let you know if lime is required to raise the pH. The fertilizer should be incorporated in the same two-inch layer of soil where the bulbs are being planted. If you have problems with critters eating your bulbs, cover the bulbs with a half-inch wire mesh.

With bulbs, bigger is better. Always choose high quality large bulbs. The bigger the bulb the larger the flower will be. Remember the bulb stores the energy for next year’s flower. If the bulb is not large enough, there may not be enough energy stored to flower next season.

Bulbs look better when planted in groups. To do this it is easier to excavate a large area at the proper depth and position all the bulbs at one time. The general rule of thumb is to plant the bulb at two to three times the height of the bulb.

Bulbs can be layered to extend the bloom. Different bulbs can be planted in the same hole with a layer of soil in between the bulb types, kind of like making lasagna based on size of bulb and recommended planting depth, In addition, bulbs of the same type but with different bloom times can be planted together in the same hole to extend flowering. This technique works especially well with annual tulips.

Bulbs are a reminder that we gardeners are optimists. We plant them in the fall with the hope for a beautiful spring.

Michelle Wallace is the Consumer Horticulture Agent for the N.C. Cooperative Extension Service in Durham Co. If you have general garden questions, contact the Durham County Extension Master Gardeners at 919-560-0528 or email

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