Bulbs

By: Michelle Wallace, Consumer Horticulture Agent – Durham

I love fall, it’s my favorite time of year. It is usually the time of year I rescue my garden from the weeds which established themselves when the heat of the summer was too oppressive for me to get down and dirty. The gardens fall colors of yellow, orange, and red warm me up even though the temperatures outside are beginning to drop. The prospect of gardening outside in mild temperature is a definite motivator combined with the fact that fall is one of the best times to install new plants in the garden.

Gardeners are strategic yet patient planners. We have to be, patience and planning are required since plants must establish themselves in their new homes, develop strong root systems and months later bloom. This is a great time of year to plant spring flowering bulbs. They can easily be combined with winter annuals and spring flowering perennials. They add color and extend bloom. Generally, they need full sun 6 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.

Bulb – form plants are 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 moist well drained soil – preferably a sandy loam. Most of the triangle has clayey soils that have poor drainage. To improve the drainage of clayey soils a generous amount of compost must be incorporated. Spread a 4” layer of compost over the planting area then till it into the top 12” of soil. If the soil has excessively 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. Bonemeal is an excellent organic fertilizer for bulbs with a low nitrogen and high phosphorus ratio of 1:3:2. We always recommend soil testing first prior to adding fertilizer. Our soils are generally very acidic. 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 surround them with a ½” wire mesh. This will prevent the critters from eating the bulbs yet allow them to grow and flower.

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. Bulbs look better when planted in groups. To do this it is easier to excavate a large area at the proper depth and lay out all the bulbs at one time then back fill. The general rule of thumb is to plant the bulb at 2 to 3 times the depth of the height of the bulb. There are charts available for the different bulb planting depths at http://trace.tennessee.edu/utk_agexgard/59 .

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 different bulb types based on size of bulb and recommended planting depth, kind of like making lasagna. In addition, forced 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. For more information on planting bulbs, contact the Durham County Extension Master Gardeners at 919-560-0528 or email us at mastergardener@dconc.gov

Spring Flowering Bulbs