Herb bennet

Hidden amongst hedgerows, herb bennet is an easily overlooked but valuable native wildflower. It makes a great addition to shady spots and wildlife areas, but can become too numerous in borders as it spreads easily by seed.

© Shutterstock
© Shutterstock

Quick facts

  • Herb bennet’s botanical name is Geum urbanum; it is also known as wood avens 
  • It is a UK native perennial of woodland and shady hedgerows 
  • Small summer flowers are great for pollinators and its leaves are a food plant for the caterpillars of the grizzled skipper butterfly 
  • Individual plants rarely spread far by rhizomes (underground stems) but do self-seed readily 
  • If you wish to remove herb bennet, non-chemical controls are easy and effective

What does herb bennet look like?

Herb bennet is an evergreen perennial that grows to around 60cm (2ft) tall. Its leaves are arranged at the base in a rosette and have up to five lobes, with the largest lobe at the tip. They are deep green and toothed at the edges.  

Slender, upright, nodding stems bear yellow, five-petalled flowers between May and August. These are followed by rounded clusters of red-hooked seeds.  

Underground, herb bennet grows from a short, horizontal rhizome and produces a tangle of wiry roots.

Did you know?

The common name herb bennet is thought to come from the Latin herba benedicta meaning ‘blessed herb’. This is because its roots and leaves were traditionally used in herbal medicine to treat a variety of digestive problems.

Is herb bennet a weed?

Herb bennet is a native wildflower, found throughout the UK in woodland and along shady hedgerows. It is an RHS Plant for Pollinators, with its summer flowers attractive to hoverflies, small beetles and flies such as the St Mark’s fly. Its leaves are also a food plant for caterpillars of the grizzled skipper butterfly and riband wave moth.

However, as herb bennet self-seeds, and its hooked seeds are easily distributed on clothing and animal fur, it can quickly spread around a garden and become a nuisance in borders and at the base of formal hedges.

What is a weed?

The term ‘weed’ describes a plant that is growing where it isn’t wanted. Weeds usually thrive in average garden conditions, reproducing and spreading easily. It is up to you to decide what you call a weed and what you choose to retain or remove.

Frequently asked questions about controlling herb bennet

Here are our answers to your most common questions about dealing with herb bennet:

How invasive is herb bennet?

Although herb bennet grows from a rhizome (underground stem), individual plants don’t tend to spread far. They do self-seed readily however, and the seeds are easily moved around a garden on clothing and animal fur, so a single plant can quickly become several. The good news is that deadheading stops plants from setting seed and it is easy to remove seedlings from any that are missed.

Preferring moist, shady places, herb bennet is less vigorous in dry soils and sunny positions.

Do I need to get rid of herb bennet?

No – allowing herb bennet to grow in a wildlife corner, shady border or at the base of a mature hedge is a great way to boost the biodiversity of your garden. It also allows you to enjoy its bright, summer flowers and support your garden’s wildlife.

It is, however, a good idea to limit the spread of herb bennet by deadheading plants before they set seed and removing any seedlings that appear where you don’t want them. This is particularly important where you sow seed or grow small plants, such as in veg beds or an alpine rockery, to prevent them being swamped or outcompeted.

What is the easiest way to kill herb bennet?

If you have herb bennet growing where it is not wanted, there are a few ways to remove it: 

  • Fork out individual plants – use a hand fork, inserted to its full depth, to prize the roots from the soil. Target your fork at the base of the rosette of leaves to minimise soil disturbance. For best effect, do this in spring to remove plants before they flower and set seed.  
  • Smother seedlings – apply a mulch of organic matter, around 10cm (4in) thick, to your soil in early spring to smother emerging seedlings. Alternatively, fill gaps in borders with ground cover plants.  
  • Avoid disturbing the soil – herb bennet can regenerate from rhizome fragments, so avoid chopping them up by hoeing or digging over the soil where it grows.

Should I use weedkiller?

No – hand removal of herb bennet is easy and effective, so there is no need to use a weedkiller.

Herb bennet is likely resistant to most lawn weedkillers, as is the case for related genera like Potentilla reptans (creeping cinquefoil), and other weedkillers are difficult to apply without harming nearby plants.

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