Avoiding Yew Hedging Bronzing

By Stephen Melhuish

Yew (Taxus baccata) is a plant chosen by many to use as hedging for its dark clipped appearance, creating a formal structural element within any garden space.

It’s certainly something that we would all love to grow healthily and remain a rich green throughout each season. The truth about its appearance is that sometimes we may notice smaller patches of a contrasting colour – a tint of bronze – which, with Yew, we refer to as ‘bronzing’. There can be a host of reasons why this may occur. In this article, I hope to shed some light on why this is happening.

Before I get into the details, it is generally accepted that much of this bronzing is caused by the plant suffering from stress. If we understand that, then we stand a better chance of being prepared to either remove those conditions that may have led to that stress or, better still, not choose the plant at all if the conditions are so severe that Yew is not suitable for planting there.

It’s best to be honest and realistic from the outset.

I would list the following as main contributors to stress in yews:

  • An imbalance in nutrients
  • Windburn
  • Heavy Frosts
  • New growth
  • Hot/dry weather
  • Severe wet
  • Sudden changes in weather conditions
  • Root rot, poor drainage, Phytophthora
  • Starvation
  • Cats and Dogs
  • Ground shock

One or any number of the above can contribute to bronzing.

Avoiding Yew Hedging Bronzing

Typical bronzing on Yew (Taxus baccata)

A brief explanation of the above contributors:

1) An imbalance of nutrients:
Food from the soil can be hampered in reaching the feeder roots of the plant if conditions are poor. It’s not enough to just feed a plant if other factors will not allow the food get to the roots.

2) Windburn
This can be frustrating and often affects newly planted Yew within their first few formative years of growth, or just on new growth generally. A more sheltered position will certainly protect tender new canopy shoots from desiccating.

3) Heavy frosts
Similar to that of windburn, and often seen after a period of severe frost, this again tends to be prevalent on younger plants within the first few years of establishment.

4)  New growth
New growth might not always be a healthy green due to some of the reasons set out in this article. Generally, you should be patient and allow the plant to acclimatise to its surroundings. Again, the magic “three years” can help. Often by the fourth year, the ground’s natural Mycorrhizal (good fungus) will help to better feed the whole plant.

5)  Hot/dry weather
Moisture, rather than dry conditions, is better for many plants, but as global change continues, spring is starting to become drier and hotter. Add to that a dry summer (as was the case this year) and you will begin to understand that the young sappy roots can dry out too. The addition of a mulch to the ground around the base of plants can help prevent moisture loss after rain or hand watering. Read our blog on making your own homemade mulch by clicking here.

A soil that is too dry will not allow nutrients in the ground to be synthesized by a plants feeder roots as moisture is the key to the good uptake of food.

6)  Severe wet
Probably the most common problem for Yew bronzing. If you have heavy clay soil, rainfall may not drain through the soil and pass by its roots. If this occurs, it can lead to standing water around a Yew root, which is a dreadful combination. Proper preparation of the soil is key here and that means taking steps to ensure that water does not accumulate around the fine fibrous roots of the plant.

Dig a much wider area than that of the root ball from the pot and improve the ground with compost. Add sharp sand and grit if needed to aid drainage too. It is essential that the soil you plant into is loose when lifting a fork through it – you should see it fall easily through its tines.

Avoiding Yew Hedging Bronzing

Typical appearance of dying and bronzing of Yew hedging on clay soil

7)  Sudden changes in weather conditions
Young plants suffer the most from sudden changes in weather. Not much can be added here other than to be realistic. Sudden changes in temperature is often a clue to bronzing. Again, recovery time may be needed for growing out and later greener shoots to appear.

8)  Root rot, poor drainage, Phytophthora
This is linked completely to severe wet.  Phytophthora is a genus of plant-damaging oomycetes (water moulds) – once this has taken hold in the plant root within the soil, it will cause all kinds of stress and damage to the root and, therefore, impact the whole plant. Bronzing in Yew is often a sign that this may have occurred. If your ground remains too wet, even after improvement, it is often wiser not to plant in that same soil again as the same problem will occur again. Avoidance is the solution here, so choose a plant that is more likely to suit wetter conditions.

9)  Starvation
Much rarer than any of the others above, but this can occur if the ground is both dry and compacted. Even if the ground has an improved hole to plant into, it still might not be sufficient for later roots to thrive beyond that hole if compaction continues beyond it. In this case, much deeper and wider preparation is essential to prevent a situation of low nutrients. Think like the plant here. Be realistic about the planting site and never plant into ground that is not suitable for long term healthy root growth.

10)  Cats and Dogs
Dieback in yew can often be caused if cats and dogs use the hedge as a toilet. The build-up of uric acid does the damage here. If you can protect your Yew plants from this then they will have a chance. This is a very frustrating common occurrence, especially if part of your hedge is on a corner or on a dog walking route.

11)  Salt
In winter, roads are often salted to prevent ice. The melting snow or rain thereafter can allow the salt to build up in puddles, likely to be splashed by passing vehicles onto the base of a Yew hedge if it is situated close to the roadside. Salt creates die back and large brown patches at the base of the plants. Smaller amounts of salt absorbed into the roots can lead to stress and bronzing. Avoidance is the best answer here, wherever possible. Yew planted behind a wall backing onto a road is much less likely to suffer.

Avoiding Yew Hedging Bronzing

12)  Ground shock / transplant shock
This is a term used when talking about the time it takes for a plant and its roots to get established after the change from compost in a pot to real soil in the ground. An average soil that is not perfect, but good enough for roots to grow and survive, might lead to some bronzing while the roots acclimatise to their surroundings.

Conclusions:

Take some time to really assess the soil conditions prior to choosing Yew, and if the site is not suitable, consider alternative options. It can be a temperamental plant, but none-the-less is a great and beautiful one if the conditions are right.

Take heart and be patient. Instant gardening practices have led to some unrealistic expectations and it is important to remember that plants take time to get established. This might mean leaving a bronzed plant in for a season or two to see if it improves with time.

Always test your soil to prevent disappointment. Get to know your soil. After all, its where the plants that you choose will spend the rest of their lives.

Avoiding Yew Hedging Bronzing

Healthy potted Yew (Taxus Baccata) Topiary Balls

Avoiding Yew Hedging Bronzing

Healthy Potted Yew Hedging Plants at Nicholsons Polytunnel

Nicholsons grow Yew in balanced conditions within our Polytunnels to control just the right amount of healthy root while in the pot so they are just right for planting out into good soil. Come and see our range and talk to a member of the plants team. If you can’t visit us, then feel free to call on o1869 340342 (option 1) or email plantsales@nicholsonsgb.com.

Avoiding Yew Hedging Bronzing