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.
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 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 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 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 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.
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.
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.
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.