weeds in ireland

Recognising Common Garden Weeds – Annual Weeds

Andrew – April 6, 2016 June 9, 2020

Of course weeds are a large part of our gardens and are plants we have to keep an eye out for especially before they manage to sow seed and multiply. If you do keep a strict and thorough weeding regime and keep the spread of seed to a minimum this particular chore will get much easier as the years go by. You will also find by using a ‘do dig’ method and adding compost and manure to the surface of your garden rather than digging it in you will reduce them amount of dormant weed seeds brought to the surface to germinate.

Some of the most difficult weeds to get rid of are the annual varieties as they are such prolific seeders and grow so quickly, I have included the most common varieties below including photos and descriptions. I general I have shown them in their more immature state as this is the point you will need to recognize them and get rid of them.

Chickweed grows to about 5-7 cm high and has a vigourous spreading habit, small white flowers and an extensive root system.

Chickweed is probably the most common annual garden weed. Seeds germinate easily in damp soil in Spring and Autumn or throughout the Summer in a wet year.

Chickweed sets seeds quickly so remove any seedlings you see by hoeing in dry weather or pulling by hand if soil is too damp to hoe. Each plant produces 2,500 to 15,000 seeds which ripen five to seven weeks after the parent plant germinates. Plants are hardy so will survive mild Winters where it can take off quickly and set seed in Spring before you notice!

Fat Hen
Fat Hen grows us to 27cm high with broad leaves and small indistinct green/white flowers. Related to tree spinach, fat hen was eaten as a vegetable in neolithic times and is rich in vitamin C.

Fat Hen is found on rich soil so is commonly found in the vegetable garden. Seedlings germinate in dense patches and look harmless at first but quickly grow into large plants if allowed to remain.

Hoeing seedlings when small is the easiest method of control, usually twice if large numbers of seedlings have germinated. Seeds persist for a long time in the soil and will germinate readily even after 20 years when brought to the surface.

Charlock is a common weed when ground is disturbed and grows up to 60cm high with yellow flowers. You will often see large patches of charlock which can easily be confused with the oil seed rape due to its sea of yellow flowers.

Seed are set in 8-10 weeks and will germinate in nearly all seasons especially in Spring. Charlock is a fast growing weed of the brassica family and is easy to how when young or easy to pull our if allowed to grow a larger plant. As with all annuals remove before it can set seed or it will become a much bigger problem. Remember as it is a brassica it can harbour pests and disease from that family so needs to be kept out of other crop rotations.

Groundsel grows to 5-22 cm high, it has lobed leaves and small yellow flowers that form seed heads similar to dandelions.

Groundsel sets seed within 4-6 weeks so you need to be vigilant, one small plant will set hundreds of seeds dispersed over a wide area by the wind. Seeds will germinate throughout the year apart from mid winter and will quickly establish on fertile soil.

If soil is dry or shady the plants will set seed when young so keep an eye out under shade plants like parsnips, courgettes or cabbage. Remember to remove any flower heads after hoeing as they will still make viable seed even if left uprooted on the soil.

Common Fumitory
Common Fumitory grows to a height of 10 to 40cm on long slender branched stems. The stems support light, feathery leaves and numerous purple-pink flowers.

Fumitory likes undisturbed ground so will be more common on the verges of your garden where the delicate pink flowers are very attractive. The plant is easy to control by hoeing and while it seeds remain viable for a long period of time it is not considered as a particularly invasive weed.

Hairy Bittercress
Hairy bittercress is a compact plant growing 3-5cm high with tiny white flowers.

Seeds are set in 4-6 weeks with an explosive seed mechanism by which seeds can be dispersed up to 1m (3ft) away or considerably further if carried by the wind. The diminutive size of the plant also makes it easy to miss allowing it to scatter its seeds unnoticed.

Bittercress is a weed of cool moist conditions so improving drainage will help control. It is also commonly seen growing on the surface of compost in nursery plants and can be unwittingly introduced to gardens from container grown plants.

Prickly Milk (Sow) Thistle.
Can grow up to 90cm high but often smaller with pale yellow flowers.

Seeds are set in as little as four weeks if the plant is in a dry and shaded position. Sow thistle needs to be spotted and removed early as if has a strong tap root making it difficult to eradicate when established and will set hundreds of seeds.

Sow thistle will germinate in a wide variety of conditions throughout the year, even over winter in mild years. There is also a similar perennial sow thistle whose fleshy roots are quick to colonise but can be easily removed as seedlings to keep them under control.

Oxalis only grows about 5cm high but is a very prolific seeder. I had some in my tunnel a coupe of years ago and quite liked the look of is so left it be, big mistake as it’s now all over the place.

Seeds are dropped from barely visible pods before you even notice it’s presence. You need to keep your eye out for this one because once present it will multiply very quickcly. Oxalis is often an unwanted passenger in nursery plant pots.

Shepherds purse
Shepherd’s purse consists of a cluster serrated leaves with a long slender flower head 5-10cm tall. Before they produce their flower stem Shepherd’s purse can be easily confused with a dandelion leaf.

Seeds are set in 6-8 weeks in green heart shaped seed pods (or purses, hence name). Once the flower stalk has been produced the plant will have grown a deep tap root which can be difficult to remove. Like most weeds, it is a good idea to hoe young seedlings early.

Speedwell is a ground hugging Spring and Autumn weed with prostrate foliage and pretty pale blue flowers.

I have a mat of speedwell under a beech tree on my lawn and am quite happy to leave it there, its low growth habit means it survives the mower.

Speedwell sets seeds in 4-6 weeks but is easy to control by hoeing or pulling out when small. Plants become more difficult to get rid of if allowed to grow into larger clumps but this is unlikely in a busy vegetable garden.

Recognising common garden weeds and understanding their growth habits helps you keep them under control and keep your garden productive.

Recognising Common Garden Weeds – Perennial Weeds

Andrew – April 12, 2016 June 8, 2020

Perennial Weeds
Perennial weeds come up every year from the same plant and are difficult to get rid of but not as hard as they are often made our to be. Most have deep tap roots which need to be removed but once this has been done smaller regrowth can be dealt with relatively easily. Other perennials with different growth habits are daisy, plantain, sliverweed and creeping buttercup which all need vigilance to remove tenacious shallow roots but are still relatively easy to eradicate.

Perennial weeds will be your biggest problem when starting a new vegetable garden on a new plot but once you have got rid of them they will be much less of a problem than annual weeds.

Field Bindweed
Bindweed is a very invasive climbing shrub with white or pink trumpet shaped flowers. Hedge bindweed is easier to control by continually pulling any small stems you see or using a trowel to remove any accessible roots. By constantly removing any foliage the roots will starve and eventually die after on or two years of constant attention.

Field bindweed is not as easy to see and is more enduring with constant removal of roots difficult and time consuming. A thick mulch can help suppress its vigour but infested areas will probably always need some annual attention.

Brambles always look far more difficult than they actually are due to their tangle of long thorny stems. Get a good thorn proof pair of gloves first and remove all the stems, removing the roots is actually relatively easy by forking out.

Mulching will help after the ground has been cleared though strong stems can push through. Digging any new stems over a period if a year or two should see a problem patch successfully cleared.

Creeping Buttercup
Creeping buttercup is a weed common to waterlogged ground and can be difficult to remove because of its tough, shallow roots. Mulching is effective outside the growing season but when growing vigorously roots will need to be dug out. Roots are shallow and tenacious so will need to be lifted with a good amount of soil and shaken off.

Remember the ‘creeping’ part of the plant name because, like strawberries, buttercup will produce rhizomes with new plants at every node so will quickly colonise an area.

Couch Grass or Skutch Grass
Couch or Skutch Grass is very common in most gardens and is very likely to be seen in ground which has been compacted or over cultivated at any stage. If growing through light friable garden soil it is relatively easy to remove by following the roots and gently pulling them out. New grass will grow from any root particles left in the soil so 2 years may be a more realistic time to clear you plot.

Skutch grass is also kept under control by applying nurtient rich mulches to the surface of the soil as it prefers a more compact and less fertile soil.

Creeping Thistle
Creeping thistle can be relatively easily eradicated by continually pulling up small plants making sure you also remove the long tap root. Loosen the soil around the thistle with a trowel and with gloved hands grasp the fleshy stem and gently pull as much root as you can.

You will not be able to extract all the root so keep pulling any new seedlings that may come up which will soon exhaust the parent roots by cutting off its source of sugars. Large patches of creeping thistle can initially be daunting but can be cleared with persistence.

Dandelions will take 6 to 9 months to get rid of by digging out small roots with a trowel or removing larger specimens with a spade. Try to remove as much of the parent root as possible so there is little left in the soil to re-grow.

Although dandelions are a common weed which spread easily from their root fragments or from their many windblown seeds they are also valued for their medicinal qualities and culinary uses. Dandelion is from the same family (Asteraceae) as lettuce and endive and so share their bitter taste. The leaves are diuretic which cleanse the liver and can be eaten in salads for their rich mineral content.

Dock Leaves
Dock leaves look much more difficult to get rid of than they actually are. They can be more tricky if growing around the woody stem of a plants like currants or raspberries (which is why you should always make sure your site is clear before you plant) but if out in the open they are relatively easy to eradicate with a sharp spade.

Slicing through the tap root about 15cm (6inches) down and removing as much as possible will usually prevent it from re-growing. Smaller plants can be pulled in loose soil or dug and removed with a trowel.

Once seed heads mature they produce large clusters of brown seeds which are best burnt rather than risked in a hot compost pile. Dock leaves without seeds can be composted with other green material. Remember Dock leaves are friends and well as foe and will soothe skin stung by nettles by rubbing on the affected area.

Ground Elder
Ground elder will regrow from roots left in the ground so try to dig along their length and remove rather than breaking them. The roots travel horizontally rather than vertically and wind themselves around the roots of other plants which can make them difficult to eradicate in busy beds. Digging root fragments is the only option, when you see a new seedling emerge followed by mulching to exclude light.

Ground Elder is a member of the Umbellifer family (celery and carrot) and has edible leaves which can be used as a filling for omelettes in early Spring when little other greenery is available.

Mare’s Tail
A very difficult weed to get rid of due to the fact that the smallest fragment of root will produce a new plant. The plant is a remnant from a prehistoric time which will give you some idea of its vigour, it has deep roots and spiky, jointed foliage.

Digging the roots is not a good idea as you will spread the plant. The best way of dealing with is with a heavy mulch followed by very frequent hoeing to starve the roots, this can take 3 years or more. If you are tempted to use the dreaded roundup it also puts two fingers up to Monsanto, it doesn’t seem to have any effect whatsoever.

There are two types of plantain; the broad one (pictured) and the narrow leaved variety. They are more commonly seen in poorly maintained lawns but can also be seen in the vegetable garden especially on paths where soil is compacted.

Dig and remove plants before they have had a chance to set seeds which they do in tall spear like seed heads. Plantain has a long tap root, you will need to remove as much as possible as smaller parts of root will re-generate.

Plantain does have an antiseptic quality and can be used to relieve itching and redness form mosquito bites by crushing a leaf and rubbing on the wound.

Rosebay Willowherb
Willowherb is an invasive weed both from seed as well as root. Immature plants can be initially mistaken for lamb’s lettuce. If small seedlings are allowed to grow they will send out tenacious roots and white stems just below soil level that will remain for many years. If you are persistent stems can be removed quite easily by digging with a towel followed by a light excluding mulch.

Attractive pink flowers (see header of this article) are borne on long stems in late Summer which quickly produce hundreds of seeds. If this is allowed to happen Willowherb will be a problem for many years.

Silverweed gets its name from the silvery underside of its leaves, it is common on lawns and paths but can also easily invade the vegetable garden. You are more likely to encounter silverweed in wet compacted soil with poor drainage so it is unlikely to be a big issue in your vegetable beds.

If pulled or hoed silverweed will quickly re-root so will need to be dug out. The plant will also reproduce like a strawberry by sending out rhizomes which root at the nodes and produce new plants.

Stinging Nettle
Nettles are not too difficult to get rid of by forking out plants and levering out the main mass of yellow roots, small roots will not regrow. Mature plants produce hundreds of seed which will germinate readily but can easily be hoed.

Wear thick gloves when handling large plants as stinging can be pretty unpleasant and last a long time depending on your reaction.

Perennial weeds come up every year from the same plant and are difficult to get rid of but not as hard as they are often made our to be.