Why Do American Yews Live So Long?

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American Yew, also called the Canadian Yew (Taxus canadensis), is known to live for a very long period. Long-living trees exude an elegant charm and become oddly more attractive as they age. However, it’s no mystery how American Yews get to live so long.

American Yews live long because they are highly tolerant to conditions such as low levels of sunlight, pollution, and salt. They are also moderately resistant to pest attacks and keep forming new roots throughout their lifespan, allowing them to keep growing.

American Yews are decorative plants, and their long lives make them very suitable for your garden, given that they are well-maintained. This article will help you better understand American Yews and why they live so long.

How Do American Yews Get So Old?

American Yews have been around for a long time and have been known to last hundreds of years. Their unusually long lifespans, gorgeous fiery red fruits, and evergreen nature make them excellent groundcovers for the forests or your garden.

The same is true for the entire Taxaceae family of trees and shrubs. Their lifespans have been a topic of discussion for years. 

The following are the factors contributing to the long lives of American Yews:

High Shade Tolerance

American Yew plants are often exposed to more shade than sunlight as a coniferous shrub commonly found in forested areas. While this would be bad news for most plants and trees, it is ideal for American Yews.

They are known to thrive in shady areas. This helps them survive in places with long winters and lesser sunlight availability. This also means that they can be planted in the shaded areas of your garden where other plants or trees simply refuse to thrive (source).

Tolerance to Shearing

It is a common trait of all members of the Taxaceae family to spread quite far and wide. This can, however, prove to be obstructive, especially in a domestic setting. This calls for frequent shearing of the plant. 

Another reason you might want to prune your American Yew shrubs is to shape them and make them look less shabby. Or, there may be dead foliage on your American Yew that you might want to get rid of.

While many plants may succumb to frequent shearing and stop growing taller, the American Yew keeps sprouting newer branches. This is essential in extending the plant’s life, as a halt in new foliage growth can cause it to rot and die (source).

Formation of Fresh Roots

One of the unusual yet valuable features of the plants belonging to the Taxaceae family is their ability to keep forming new roots. They merge branches and sprout new roots when favorable conditions are present. 

When some low-lying branches of two American Yew plants overlap, they form arches. These arches, bearing a lot of foliage, tend to droop even lower and come in contact with the ground. 

When the arched branches of the trees get buried under the organic matter, soil, and plant debris, they start sprouting fresh roots. These roots spread and protect these plants from dying and continue to sustain them in case one of the older root systems fails due to root rots, diseases, or other causes. 

They also form new sites of nutrient and water consumption for the parent plants, helping them grow and maintain their health for extended periods (source).

This process can happen numerous times throughout the life of an American Yew tree and is most commonly witnessed in a forest setting instead of a domestic one. This is because the arching of two or more American Yews’ branches will only be possible in an environment where the spread of the plants isn’t subject to constant shearing or pruning. 

Pest Tolerance

Although the American Yew has toxins in almost every part of its anatomy, except for the berry flesh, several deer species seem unaffected (source). 

Deer and rabbits are likely to browse or forage American Yews in the winter but typically avoid them when there are plenty of other food sources available. While American Yews aren’t entirely resistant to pests, they are relatively tolerant towards them. 

This situation improves the American Yews’ chances of survival. In addition, their ability to re-grow roots from low-lying branches helps them bounce back during spring.

As far as insects are concerned, the leaves of the American Yew plant are pretty well defended against them. Research also suggests insect eggs exposed to American Yew leaf extract tend to have higher mortality rates (source).

Pollution Tolerance

One of the major issues affecting plant health these days is air pollution. This is because most plants absorb harmful gases, such as sulfur dioxide, ethylene, and nitrogen dioxide present in the atmosphere. These gases cause damage on a cellular level in the plants they affect.

The main inlets for these gases are the pores on the underside of the leaves of most plants. However, the leaves of the American Yew don’t absorb these gases as much.

This makes them more tolerant of pollution and helps increase their lifespans, especially when planted in urban areas with higher levels of air pollution.

Salt Tolerance

Another issue that affects the health of a plant is the amount of salt in the soil. While salts are also necessary for plant growth, an excess of the same salts can be very dangerous for most plants.

This is especially true if there isn’t a sufficient water supply available to distribute the salts in the soil properly.

In coastal areas, the salt concentrations in the ground can also be very high.

However, the distribution of the American Yew plants in the US suggests that these plants can also thrive in coastal/island regions. This means that they tolerate more significant quantities of salt in the soil (source).

Conclusion

Like all other Yews, American Yew is famous for its long lifespan. This characteristic of American Yew makes it an excellent groundcover for the forests and a great addition to your home garden.

Several traits contribute to the longevity of American Yew plants, including the following:

• shade tolerance
• tolerance to shearing
• formation of new roots
• pest tolerance
• pollution tolerance
• high salt tolerance

Recommended Reading:

• Are American Yew Trees Poisonous To Touch?