Dandelions came over with the early settlers and have been spread to most parts of the province by animals, people and vehicles. The yellow flowers are so much a part of the spring landscape that there is no chance of eradicating them.
Each spring, a flush of yellow spreads across fields and lawns, followed by white seed heads. Once the initial flush is finished, an occasional yellow flower will appear.
Dandelions receive a mixed reaction.
They are hated by some and ignored by others — and a few people like them.
Dandelions can be killed by using chemicals, digging, improving the soil or a combination of all methods.
There are a number of products on the market licensed to kill dandelions. Products are sprayed onto the plants leaves, where they are absorbed by the plant and move throughout its, system killing it.
For the chemicals to work, the plant must be actively moving nutrients throughout the plant. People tend to spray when the dandelions are in flower but the chemicals work best in the fall when the plant is preparing for winter.
It is easy tell plants that have been sprayed as the broadleaf plants elongate, curl and die.
Use chemicals that are licensed for broadleaf weeds in the lawn to kill dandelions. Agricultural chemicals are not licensed for lawns and can have a detrimental effect on trees and shrubs. Read up on the active ingredients of all chemicals before using them. Know what they kill and how long they will reside in the soil. Always read and follow the instructions on any chemical package.
Use caution when using a home recipe. Vinegar, even horticultural grade, might burn the tops of the plant but not the roots. Salt has been used for centuries as a soil sterilant.
Digging dandelions is tedious but effective for small infestations. The complete root must be removed to kill the plant. Usually the root will break off when it is being dug out and need to be removed once it has regrown. Continued digging will eventually kill all plants.
Dandelion seeds are opportunists. They will sit on top of the grass and germinate only when they land on a piece of open soil. A healthy lawn that is growing well will have few bare spots, meaning less dandelions.
Soil is the most important part of the garden, including the lawn. If the soil is not healthy, then neither will the lawn. That means that weeds can easily become established. When putting in a new lawn, make sure there is a deep base of at least 12 inches (30 cm) of top soil that is high in organic matter. Organic matter plays an important role in soil. It contains nutrients and keeps the soil soft. It also binds with clay, making it possible for the plants to absorb nutrients from the clay.
Soil conditions in older lawns can be improved. Soil compacts with age, making it hard for plant roots to spread and grow. An easy way to test soil compaction in a lawn is to push a screwdriver into the ground in a number of places. If it sinks easily, the soil is not compacted.
Areas that withstand the screwdriver need to be aerated.
Rent or borrow a machine when the soil is moist and plugs come out easily. Plugs that are left on the lawn initially look messy but will quickly break down to become part of the lawn. Soil will become less compact as it spread into the holes made by the aerator.
Do not aerate with tools that just poke holes and not remove plugs. This just causes the soil to become more compact in different areas.
Up to a half an inch (one cm) of thatch is good for the lawn. Thatch, the dry grass around the roots, protects the lawn from fluctuations in temperatures, shades the roots and helps keep the soil moist. Too much thatch will choke the grass; too little will expose soil and roots.
Using a bagging lawnmower will reduce the amount of thatch, as will raking or dethatching each spring.
When too much nitrogen fertilizer is used on a lawn, the grass grows very quickly, adding to the problem of too much thatch. Use a fertilizer that contains both nitrogen and phosphorous, applying at the rate recommended on the bag.
Spreading corn gluten on the lawn will stop all seeds from germinating.
If a lawn full of yellow flowers is a problem, there are options available to the homeowner. Choose ones that are safe to you.
Linda Tomlinson is a horticulturalist who lives near Rocky Mountain House. She can be reached at firstname.lastname@example.org.