Tulips (Tulipa spp.) provide a glimpse of spring in late winter as their sprouts emerge from the ground. Hardy in U.S. Department of Agriculture (USDA) plant hardiness zones 3 through 8, these perennials are often transplanted for landscaping redesign or storage after blooming. If you remove fibrous roots from tulips' bulbs, the tulips can still grow as long as the bulbs' root generation area, or basal plate, remains intact.
A flower bud resides at the center of a tulip bulb and is surrounded by white scales. Acting as nutrient storage, these scales keep the bud healthy and nourished until spring arrives. The scales and flower bud are held together by the bulb's basal plate. Forming the bulb's flattened end, roots grow from the basal plate when the bulb is planted. Cutting roots off a tulip bulb does not harm the bulb but simply stimulates more rooting activity. In fact, offsets, or bulblets, slowly grow around a bulb as they form their own buds and basal plates, making rooting a constant activity during the growing season.
Every three to five years, tulip bulbs need to be divided. Offsets typically strangle their mother bulbs as they enlarge, causing reduced flowering. Carefully dig up your tulip bulbs after the tulip leaves are yellow and papery, or about six to eight weeks after blossoming ends. Tulip leaves need to photosynthesize as much as possible to store nutrients in the bulbs for next year's flowers. Use a blunt shovel or garden trowel to remove the bulbs from the ground. Offsets may simply fall off mother bulbs, or you can cut them away from the mother bulbs by using a clean knife. If a bulb's fibrous roots are cut or damaged, the bulb replaces them during the next growing season.
The best planting time for tulip bulbs is fall, but they require a chilling period of up to two months to stimulate sprouting. So plant them in fall if you live in a cool USDA zone, where the bulbs chill naturally. In order to sprout successfully in spring, tulip bulbs in USDA zone 8 require time in a refrigerator set at about 40 to 45 degrees Fahrenheit, which replicates the effects of a cold winter. Plant bulbs in USDA zone 8 during December and January for late-winter or early-spring blossoms. The bulbs should be planted at least 6 inches deep in soil to create a strong root system and sturdy stem structure.
Regardless of whether or not tulip bulbs' roots are attached or detached, the bulbs fail to sprout and flower if they are waterlogged. If soil remains wet, rot quickly sets in, decimating the bulbs. Planting sites should be well-drained and receive full sunlight. If you leave dead foliage or flower heads on the ground, they can harbor pathogens that may infect the bulbs, especially if they are not dug up and transplanted or stored. Proper garden maintenance preserves tulip bulbs for yearly blossoming.
- University of Florida IFAS Extension, Miami-Dade County: A Word or Two about Gardening -- Ornamental Bulbs for Miami-Dade
- Royal Horticultural Society: Bulbs -- Propagation
- Burpee: How to Divide Spring Bulbs -- Tulips, Daffodils, Crocus and More
- International Bulb Society: Flower Bulb Basics and Frequently Asked Questions
- Oregon State University Extension Service: What to Do with Your Withered, Finished Hardy Spring Bulbs
- Annenberg Lerner, Journey North: Teaching Suggestions -- Tulip Bulbs: The Inside Story
- The Old Farmer's Almanac: Tulips
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