Why is my Taxus turning brown?
Although Taxus baccata is an extremely robust and reliable plant once established, with a lifespan of say 4000 plus years; it can often show signs of failing to thrive after planting which can be disconcerting.
A very common question we get asked as a garden design studio is “Why is my taxus going brown?” Bronze foliage is probably the most common affliction of newly planted Yew and can be especially noticeable in hedging when individual plants go bronze, contrasting with their lush green neighbours. Unfortunately, there isn’t really a one size fits all answer but, in all cases, it is a sign that the plant is currently experiencing or has previously experienced some level of stress. There are many reasons why this may occur, and finding the cause is a process of elimination and observation.
New growth – Soft, young yew growth is very often light bronze in colour and it greens up as it hardens off. If it doesn’t green up as the foliage matures, the bronzing will be due to another reason.
Severe wet – Almost certainly the most common problem for Yew bronzing is wet feet and over watering. If you have heavy soil that does not drain well, it can lead to standing water around the roots which often leads to rot and disease setting into the root system. Planting preparation can make a big difference if soil is not ideal to begin with. Adding grit to the whole area and installing a land drain may help but alternative evergreens such as Prunus lusitanica are a good evergreen alternative for heavy soils.
Phytophthora – Linked to the problem above, Root Rot is caused by a fungal pathogen known as Phytophthora which destroys the feeder roots of susceptible plants and prevents them accessing food and water. It thrives in soil suffering from prolonged wetness and is particularly common in autumn and winter months. Yew is particularly prone to this disease, and it is often fatal to all plants it infects and can live in the soil for several years. If the plants do have root rot, the bronzing tends to start where the leaf is attached to the stem. If there are still green buds on the plant, there is potential for the plant to survive if drainage improves. However, if the ground remains too wet, it is advisable to remove the plants and choose a disease resistant variety to replace them. Carpinus betulus (Hornbeam) is rarely affected and is well adapted to cope in heavy soils.
Transplant shock – Yew can be a bit temperamental after planting, particularly if the soil or environmental conditions are less than perfect. It may look unhappy for a year or two and experience some bronzing until the plant has acclimatised to the new growing conditions. If new green buds are present and the root system has fresh white growth, patience will be needed but take heart, in our experience, it will soon be looking green and healthy again!
An imbalance of nutrients – New Taxus plants can take up to 3 years to acclimatise and establish to the different conditions in your garden. Nutrient uptake from the soil is reduced until full root establishment. Often by the fourth year, the soils natural Mycorrhizal fungus has formed a symbiotic relationship with the roots and helps to better feed the whole plant. Mulching with a well-rotted, organic based compost will top up soil nutrients and improve the soil.
Windburn – This often affects newly planted Yews within their first few years of growth, or on fresh tender growth only. The wind is essentially wicking water from the leaves, and they are experiencing a drought. This means they cannot perform their internal cell processes and die off as a result. As the plant matures and hardens off and establishes a deeper and wider root system to access water, it should be better able to cope with this although rate of growth may less vigorous. Consider a more sheltered position, installing an irrigation system to increase the supply to suit demand (but do not overwater) or adding some form of protection such as a slatted fence, taller planting, or trees as a windbreak to prevent the tender new shoots from desiccating.
Heavy frost – As with windburn the young or exposed foliage experiences dehydration as it cannot access frozen water. It tends to be younger plants that suffer within the first few years of establishment and is generally only cosmetic damage that is unsightly, but the plant will recover.
Hot/dry weather – Young roots can dry out very quickly in periods of hot weather. The addition of a mulch to the ground around the base of plants can help prevent moisture loss. Make sure the mulch is added to moist soil rather than dry, as it can prevent moisture seeping into the soil if applied to dry ground. Whilst an established Yew is quite a drought-resistant plant, young plants need to receive adequate water regularly until they have established a good root system to access the water and nutrients they need to thrive. A timed irrigation system to use in the dry spring and summer months can help with establishment in the first few years but the soil will need to be well drained to prevent water logging.
Animal Damage – Dieback in yew can be caused when cats or dogs repeatedly use the hedge as a toilet area. The build-up of uric acid prevents the uptake of nutrients by changing the PH of the soil and can lead to leaf browning. Damage to the bark from rabbits or people can also have the same affect. Take care when pruning and maintaining your Yew and try to deter animals from damaging the bark or toileting near the area.
Salt – If your Yew is near a road or driveway that is treated with de-icing salts in the winter the salts can dissolve in the melting snow or rain and contaminate the soil. The adverse effects of this are usually seen in early spring. Salt splashes create die back and large brown patches at the base of the plants whereas smaller amounts of salt absorbed into the roots can lead to stress and bronzing. Avoidance is the best cure or using a large amount of water to flush the soil and wash the salt away (providing it is well drained).
Generally (with a little patience) bronzing can be cured. Yew is very tough and is able to recover even when it appears dead. If the bronzing starts at the tips of the leaves rather than the base, it is most likely not serious. To prevent stress, assess, improve (if needed) and prepare the soil before planting Taxus to ensure the best chance of success. As with all gardening and particularly new gardens, it takes time for plants to establish, and this can be anywhere from a few months to a couple of years depending on the conditions and species. There can be some very unrealistic expectations for immediate results in a culture of instant impact but don’t forget that a garden is a living entity. It may mean living with imperfection for a while, but leaving a bronzed plant in for a couple of seasons, to see if it improves with time often pays off.
