With their signature yellow flowers and distinctive tooth-shaped leaves, dandelions (Taraxacum officinale) can be found in almost every part of the U.S. Growing in U.S. Department of Agriculture plant hardiness zones 3 through 10, these perennials create 18-inch tall flower stems with a vigorous taproot diving into the soil. Their survival adaptations allow them to flourish in areas as varied as flowerbeds or gravel-covered roads.
One of the major reasons for dandelions spreading throughout the U. S. is their aggressive reproductive strategy. The flower is self-pollinating, which encourages a fast transformation from blossom to seed head. Creating a puffball shape, dandelion seed heads are commonly blown by the wind -- or a curious child -- to disperse the seeds. Each seed has fine hairs that act as parachutes. Requiring little time to germinate, these seeds can potentially float for many miles before settling in a new location. This widespread and successful reproductive strategy contributes to dandelion populations all over the U.S.
Dandelions tend to be most obvious when they grow in the middle of your lawn. The tiny, floating seeds find any small, exposed soil area in your turf and exploit it -- you can see a 14-inch wide dandelion foliage cluster appear quickly in neglected lawns. As the dandelion grows, its taproot forces its way through the soil for nutrients and moisture. Your lawn begins to feel the natural resource competition with the dandelion as the taproot grows past 10-inches long; your turf may appear brown or die back around the dandelion growth. Proper lawn management, such as rich soil and accurate watering, contributes to a dense grass that hinders dandelion growth. Another option is to shade the dandelion out with 4-inch long grass blades. If dandelion seeds or seedlings do not receive enough sunlight, they quickly die.
If left alone, dandelion roots can easily grow several feet long. With this far-reaching root ability, areas that seem impossible for plant growth become perfect locations for dandelions because they can find deeply seated moisture and nutrients with their taproot. Concrete crevices, gravel walkways, fence lines, flower and vegetable gardens, fields and construction sites are all viable locations for dandelion growth. Built for hot conditions and drought, dandelions simply need a disturbed soil surface for proper germination and growth.
U.S. locations that have freezing temperatures part of the year are not exempt from dandelion populations. In fact, the foliage and flowers die back during cold weather, but the roots easily regenerate new growth once warm weather returns to the area. Even if you have a 1-inch dandelion root section hidden in the soil, it grows quickly with sunlight, warmth and moisture.
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