The Cupressus arizonica , known as the Arizona cypress, is a conifer of American origin with resistance to areas of little rain and with a good ornamental character as a conifer. In addition, it is considered a very resistant, rustic tree with a great tolerance to urban pollution. Some varieties have blue-green needles that are very attractive. We will delve into its characteristics, care and growing conditions.

ORIGIN AND DISTRIBUTION OF CUPRESSUS ARIZONICA

The Cupressus genus is what defines what we normally know as cypress trees. You may think that there are many species of cypress as it is a very common tree in many places. The truth is that there are only 13 accepted species . There are about 200 synonyms but they are other names for these first 13 species. Cupressus arizonica is not synonymous, it is one of these species of the genus. To be fair, the full name with the species descriptor is Cupressus arizonica Greene. Edward Lee Greene was a botanist at the University of California Berkeley in the 19th century.

It is a tree native to the southwestern area of ​​the United States . The surname of the taxonomic name gives us the necessary information to infer its origin. Indeed from the Arizona area although it extends throughout the west coast and Central America (mainly Mexico). It is also developed in southern Europe, Spain being the place where it predominates . It was also brought to Australia and is present in the eastern part of the continent. Here we present a map with the quotes found in Europe and America.

The Arizona cypress is a conifer, perennial, of great size and can reach up to 20 meters in height depending on the variety. There are varieties within the species of more moderate sizes. Morphologically it is not the classic cypress, ( Cupressus sempervivens L. ) so slender and spiky and often associated with cemeteries. In this case we are facing a somewhat more open and less dense cup shape than the common cypress. Even so, it continues to have a slender bearing, a straight trunk and a slender structure with a not very wide crown. Its bark is characteristic, smooth in the young specimens that is peeling off in the adult and long-lived specimens . This creates a very attractive cup.

The growth rate is moderate . about 60-70 cm per year. According to varieties, there are them in different shades of green. We particularly like the blue-green ones that belong to the « Glauca » variety, one of the most cultivated, together with the short-growing « Compacta ». Other varieties are: “Glabra”, “Glomerata”, “Montana”, “Nervadensis” and “Stephensonii”.

ARIZONA CYPRESS USES

As an ornamental it is widely used for the following reasons:

• Possibility of forming dense hedges .
• Resistance to drought and relative little care.
• Great tolerance to different types of soil
• Resistant to urban pollution .

In addition, its essential oils have certain properties that we now discuss.

It is known that essential oils (ES) from conifers have antimicrobial activity due to their content of α and ß-pinene , monoterpenic compounds present in coniferous resin. Both bacteria Gram negative and Gram positive are inhibited by the essential oils of the Arizona cypress, being more effective on Gram negative. These compounds have some relevance in the chemical and pharmaceutical industry. In traditional Chinese medicine, coniferous resins are used as an anti-inflammatory and antiseptic .

What is curious about the studies consulted is that the antimicrobial activity is highly variable depending on the cultivation conditions (climate, altitude, type of soil, etc.), having extracted the AEs from trees in Argentina, Iran, Algeria, Texas or Italy.

Read more >> Essential oils in plants

PLANTING AND CARING FOR CUPRESSUS ARIZONICA

TEMPERATURES AND EXPOSURE

It supports full sun, direct light and very high temperatures, typical of the Arizona climate. It can withstand calmly up to 45ºC. Its resistance to low temperatures is lower. According to the USDA hardiness classification, it is between zones 7 and 9, the minimum being 0ºC in zone 7 although it can withstand light frosts and not very continuous in time. In much of the south of Spain, Andalusia and the Spanish east, these conditions will be so ideal for this conifer.

SOIL AND FERTILIZER

It is the most tolerant to all types of soil pHs . From very acidic to very alkaline and even saline in coastal areas . A soil texture also has a wide tolerance range to sandy, loamy and even somewhat clayey soils. The only point to watch is the drainage. They cannot be soils that hold too much water.

It does not need a dose of fertilizer. It can thrive in poor soils. Still, some fertilizer could be applied if faster growth is desired or the soil is known to have a significant deficiency. The type of fertilizer can typically be slow release granular.

IRRIGATION

During the first and second year, until the total implantation of the root system, it is convenient to ensure a little irrigation , especially if the seasons are drier than usual. Once the tree is rooted and the roots have sought their source of moisture in the subsoil, it is a tree with a lot of resistance to drought, and can even be included in xero-gardening in desert areas.

Withstands long droughts once rooted. Its growth is diminished in these conditions. If a little more irrigation is provided, along with some fertilizer, we can obtain a higher growth rate. Typical rainfall in Arizona is around 200-300mm per year to get an idea.

PRUNING

Everything will depend on the ornamental use we want. It is tolerant to pruning and therefore can be shaped as a hedge . In that case, we will do an annual pruning, before spring and always in young wood of the year. It does not generate new shoots in old wood and we could leave areas of bald spots if we do not form the hedge from the beginning. Occasionally and with the intention of forming the hedge in its first years of life, it can be pruned in late spring.

PLAGUES AND DISEASES

In general, it is quite resistant but it can present pests such as the cypress aphid ( Cinara cupressi ). This aphid is a large aphid compared to other aphids and is dark almost black in color and easy to identify especially if there are ants around. Causes the complete drying and falling of the tender branches (the youngest). For large trees, potassium soap may be insufficient, and systemic insecticides such as imidacloprid should be used.