(Taraxacum officinale) Dandelion “clocks” evoke memories of childhood, but in the garden those annoying seeds land everywhere, producing lots of dandelion plants that colonise large areas.
What are dandelions?
Dandelions are perennial plants that overwinter and survive from year to year thanks to their long taproot, which stores food reserves.
Although attractive when in flower, dandelions soon become a serious garden weed when present in large numbers, especially when growing close to cultivated plants and in the lawn. If left to flower and set seed, they spread even further and can soon colonise and take over large areas of the garden.
Small and young leaves can be added to salads. The dried and ground up roots have been used as a coffee substitute – possibly one novel way to control it! Just be aware that it contains a strong diuretic, which gives rise to another English folk name – piss-a-bed.
Where do they grow?
- Gravel paths
- Between paving slabs
- Waste or uncultivated ground
The leaves are lobed, 5-25cm (2-10in) long and form a basal rosette above the taproot. The name dandelion comes from the French, dent-de-lion, meaning lion’s tooth, which arises from the shape of the leaves.
The small, yellow to orange flowers are collected together into a composite flower head, and are open in the day, but close at night. These are followed by the seeds, which are very light, come with their own ‘parachute’ and are easily spread by even light winds over considerable distances.
Plants may die down to their taproots in winter, re-shooting the following spring, or remain evergreen.
How to control dandelions
As with most perennial weeds, never allow dandelions to become established. This will make it more difficult to fully control them. Early eradication is important to stop them taking over the garden.
Digging out the roots is one of the quickest – although not necessarily easiest – ways of getting rid of dandelions. You will need to dig up as much of the taproot as possible, as even quite small pieces will re-shoot to produce a new plant. A fork and hand fork are usually better tools than a spade and trowel, which will cut the roots into smaller pieces.
Rockery trowels and similar weeding tools, which have long, narrow blades, are particularly useful for digging around and getting out the whole taproot.
Covering bare soil with weed-control membrane (landscape fabric) or even thick black polythene will exclude light and may starve the roots, so they die. This can take a couple of years until the taproots are completely exhausted.
Hoe seedlings and young plants as soon as you see them. Regularly hoeing the new leaves of established plants as soon as they are seen will weaken the plant over time, but this will probably take several years to completely kill plants with large taproots – and needs lots of dedication.
In lawns, regular mowing throughout the year may weaken and eventually kill it. Although, it tends to change its growing habit in lawns, producing very low rosettes of leaves that can’t be touched by the lawnmower. Long-handled lawn weed extraction tools that grab onto the roots and pull them out are also available.
There are a number of weed control options available to treat dandelions. In addition to traditional weedkillers there are now also a range of more natural alternatives.
Contact weedkillers will burn and kill the foliage, but will have no effect on the taproots, which will continue to grow, produce new leafy growth and spread further. Constant spraying whenever new leaves are produced will weaken and kill it in time.
For best results, spray with a systemic weedkiller. A systemic weedkiller, which is absorbed by the leaves, then moves down to the roots to kill them.
To ensure the weedkiller works effectively:
- Spray the leaves when the dandelions are growing actively; this is mainly from March/April to September/October.
- The larger the leaf area present, the greater the amount of weedkiller that can be absorbed. So don’t bother spraying when the growth first emerges through the soil – wait until the leaves grow larger.
- Use a fine spray to thoroughly coat the leaves in small droplets.
- During the summer, spray in the evening to prevent the spray evaporating and to give maximum time for the spray to be absorbed. In spring or if overnight dew is forecast, spray earlier in the day to allow the spray to dry before dew falls.
- One application of weedkiller may not completely kill the dandelion. You may need to spray once, allow it to die down, and then spray any regrowth again. Three or more applications a year may be needed to completely kill it, depending on how extensive the root system is.
Most contact weedkillers are total weedkillers – that is they will damage or kill any plants whose leaves they are sprayed on. Make sure you keep the spray off wanted plants – including lawns – and, if necessary protect plants by covering with polythene or similar when spraying.
Gel, which is dabbed onto, and sticks to, the weed leaves, may be a better option when trying to treat dandelions growing close to wanted plants, where drift of the spray would damage them.
In lawns, use a good lawn weedkiller.
Use weedkillers safely. Always read the label and product information before use.
Never allow plants to flower and set seed. Although this is pretty easy in your garden, it’s more difficult to stop the seeds blowing in from a neighbour’s garden, any surrounding fields and waste ground and even further afield.
- Hand fork
- Weeding tools
- Weed-control membrane
- Systemic weedkillers
- Gel weedkillers
- Lawn weed extraction tools
- Lawn weedkillers