Weed Beater: Dandelions
Dandelion seeds can remain viable for decades when conditions are not conducive to germination.
The dandelion (Taraxacum officinale), also known as puffball, lion’s head and monk’s head is a broad-leafed flowering weed commonly found growing in areas with good drainage and direct sunlight. Dandelions were first introduced to North America from Europe, likely arriving with the earliest settlers, who carried them on board their ships for both culinary and medicinal purposes. More recently, this aggressive grower has developed a reputation as the most recognized weed invading suburban lawns. Jagged leaves growing out as much as ten inches and emerging from an anchoring taproot, the bright yellow flowers that sprout from its hollow stems make the dandelion easy to identify, but control of this well-known weed is a challenge familiar to many homeowners throughout the growing season.
Dandelions are a simple perennial and propagate through the spread of seeds. Usually triggered by frost or when daylight hours grow short, the flowers of the dandelion—each head actually a cluster of tiny flowers—dry to become the familiar white “puff ball.” Hundreds of fine hairs each hold a seed that carry readily in the wind, a single plant spreading seeds over hundreds of yards. Seeds germinate easily on or just below the surface of moist soil when temperatures remain consistently over fifty degrees. When conditions are not conducive to germination, dandelion seeds can remain viable for decades and may become active when soil is agitated by tilling or when environmental circumstances become more favorable.
The spread of dandelions can be reduced through regular lawn maintenance. Grass should be mowed regularly and to an appropriate length. Although dandelions that have been mowed down will grow back, destroying developing flowers before they are able to mature into seed distributors prevents the opportunity for new germination. Improving soil conditions through composting can also reduce dandelion growth. Although they will grow in many conditions, dandelions prefer acidic soil and adjusting the pH of acidic soil can inhibit rampant growth.
When mowing a lawn prone to weed issues, forgo bagging grass clippings. Mulched clippings left on the lawn promote grass health and also inhibit the germination of dandelion seeds on the soil surface. Mulches can also be applied to flower beds to discourage weed growth and to smother existing weeds.
Although labor intensive, hand removal of each dandelion ensures it will not return. If the root is left intact, the plant will return, so care must be taken to withdraw each dandelion completely. Water the lawn thoroughly to loosen roots. Using a screwdriver or a forked tool designed for weeding, pry each weed from the soil, making certain to extract the entire root.
If necessary, herbicides may be employed to control an extreme or persistent dandelion infestation. Herbicidal applications are most effective when applied in spring or fall. When using herbicides, do not mow grass for several days before or after treatment and plan to treat when conditions are dry for maximum efficiency. As with all chemical treatments, consult manufacturer documentation regarding proper use and safety concerns.