Hedge trees, cedar and cypress have been sharing the limelight in gardens for decades. Windbreaks, privacy screens, these coniferous hedges are very appreciated by gardeners for their thick and persistent foliage in winter. But what is really the difference between cedar and cypress?
A strange resemblance
It's hard to tell the difference between a cedar or cypress hedge!
The Lawson cypress (Chamaecyparis lawsoniana) is not a true cypress (Cupressus) in the botanical sense of the term, whereas the Leyland cypress (Cupressocyparis x leylandii), is a natural hybrid between the Lambert cypress (Cupressus macrocarpa), and the Nootka cypress (Cupressus nootkatensis)
Cedars and false cypresses are conifers, very similar in appearance that share certain characteristics:
- a green foliage (except the cultivars in vogue, golden or blue) persistent composed of flattened scales;
- a slender, conical to pyramidal habit in the first years;
- they provide compact, dense hedges, ideal as privacy and windbreaks throughout the year;
- they are well suited to pruning;
- they must be pruned once to three times a year, when they are grown as hedges to contain them.
Discreet differences
There are a few ways to differentiate cedars from false cypress and cypress trees used to create hedges:
- cedars have slightly wider, slightly less dense branches than false cypresses;
- False cypresses grow much faster (up to 70 cm to 1m/year for the Leyland cypress) and appear finer in their young age;
- several pruning actions are required to contain the false cypresses each year;
- false cypresses are a little less resistant to frost than cedars (-20°C all the same!);
- The shape of the cones is elongated on the cedars and rounded on the false cypresses;
- The scales of true cypresses are never flattened but rather spiral or 3D;
- the spire (top of the tree) is thinner on the cedar;
- There are many varieties of Lawson cypress, for example 'Stardust' with golden foliage or 'Pembury Blue' with bluish foliage.
Cedar, the star of the 80s
For decades, cedar was the dominant plant in the creation of blackout hedges.
Thuja plicata, better known as 'western red cedar', is very appreciated for its average growth (30 cm/year), which limits pruning. It has the advantage of growing in height (up to 50 m) but also in width, which ensures a well-filled and dense hedge.
- Thuja occidentalis 'Brabant', or 'Brabant cedar', has its followers because it is very resistant to cold (-25°C) and easy to maintain. Its average growth (30 cm/year), and its light green color are unanimously appreciated, especially since it only grows up to 5 m high and is very easy to prune.
- Despite all these advantages, the use of cedar in hedges is more and more controversial, especially because of its sensitivity to cryptogamic diseases (Phytophthora cinnamomi, Didymascella thujina, Coryneum cardinale...). These diseases, frequent in heavy and humid soil, cause the browning of the foliage and its fall. In the case of Phytophthora, the cedar will not survive.
Another concern is a small parasitic insect: the bupreste, which has been devastating many plantations for several years.
In southern regions, cedar can be sensitive to drought unless an automatic watering system is installed so that the tree can really produce its root system. Let's not forget that the lack of water is a stress factor, which can weaken the tree and make it much more susceptible to diseases and parasites.
Cypresses, very trendy in hedges
As we have seen, cedar has been gradually replaced by other species more resistant to diseases and pests. Cypresses grow very quickly, are very hardy and for the moment are less sensitive to pests and diseases.
They do not really appreciate very calcareous and dry soils.
Available in ornamental foliage (blue, golden...), Lawson cypresses also appeal for their ease of growing and pruning.
On the Leyland side, beware! It grows so fast that to obtain a regular hedge and keep a dense aspect, it will be necessary to prune often (up to 3 times a year) and to call a professional to avoid the formation of unsightly holes with time.
So cypress or cedar?
It's all a question of choice, but with these conifers, you will only obtain monospecific hedges, which certainly attract certain birds but will remain unicolored in all circumstances and will require very regular maintenance (pruning).
The current trend is to have a variety of hedges, composed of flowering shrubs of different species to stagger the blooms throughout the year and encourage the presence of pollinating insects. Some of them have berries that attract birds and small mammals. Biodiversity is thus favored with a better balance in your garden!
