Identifying Green Alkanet
Not to be confused with borage, comfrey and forget-me-knot, green alkanet has edible five-petalled blue flowers with white eyes.
The leaves of green alkanet are oval, large and pointed with bristles. They grow up to 40cm long from equally bristly stems. Occasionally you might see white speckles on the leaves.
By contrast, borage has lighter blue flowers that grow in downward facing clusters like comfrey flowers.
Purple comfrey flowers are more lilac / pink. Forget-me-not plants are much smaller than green alkanet with paler blue flowers growing in clusters that often have yellow centres.
Note that it is only the flowers of green alkanet that are edible - the leaves are toxic if consumed in large quantities as are the roots.
The whole plant can grow up to 1m in height, usually dying back in autumn and regrowing in spring, though it has been known to be semi-evergreen in mild winters.
Green Alkanet grows and spreads quickly via seed dispersal and underground root runners. A single plant can quickly become a very large patch. As such it can be seen as a ‘problem’ plant for many gardeners and growers.
Controlling Green Alkanet
Like many fast-spreading weeds, the key to controlling green alkanet lies in preventing it from setting seed and removing every trace of root.
Manual Removal
If your patch is currently small, try and remove it by hand first. You will need to ensure you remove the entire tap root and the runners to prevent it from regrowing. Dig the plant out rather than pulling for the best chance of removing the root system.
Root sections will survive on a compost heap and regrow there, so rot them down in plastic bags or take them to your local tip to dispose of them responsibly.
If you can tolerate a single plant or two in position for a season, deadhead them before they set seed to prevent spread from seed dispersal. If you can get rid of them when they are small, they are much easier to pull out.
Remember to wear gloves when handling alkanet as it has been known to cause skin irritation and rashes.
Chemical removal
If your green alkanet has already spread extensively, you cannot dig the plants out without impacting other plants, or you cannot remove the whole root system - use a carefully targeted application of glyphosate.
Roundup Pro Vantage contains 480g/L glyphosate and is a total herbicide meaning it will kill any plant it comes into contact with.
Therefore, unless the green alkanet is growing in an area where you intend to clear all vegetation, apply the glyphosate with a weed wiper directly to the leaves of the green alkanet only. Apply when the plants are actively growing.
Always use plant protection products safely and read the label and product information before use. For label and safety information, refer to the manufacturer’s website. Remember, only certified users may apply professional plant protection products. Find out more about safe use of pesticides here.
