The Italian Cypress is a beautiful upright evergreen that grows in a straight column up to 20 to 25 feet or more. It thrives in North Texas, but can have real problems if:
1) Planted in heavy clay soils
2) Irrigated too much
3) Experience very wet spring and early summer weather
The tree comes from the Eastern Mediterranean region which is a semi-arid (dry) climate. It is a gorgeous landscape plant used to accent architectural lines, line pathways, or provide screening in the back of a landscape. As such, it is used widely in North Texas and with some success. However, they are often planted in less than ideal locations
-Heavily mulched and irrigated areas
-Up against fences, house walls, etc. that restrict air flow around the crown
-Underneath taller trees that restrict sunlight. They require full sun
This year (Spring 2017) has seen a lot of limb dieback on Italian Cypress. Almost every tree in our area has been affected. The only ones that I have observed that are not having serious problems are the ones planted in areas that are never irrigated and that have plenty of sun and air flow around the entire crown.
The disease that is probably the culprit is Seiridium Canker, caused by a fungus in the Seiridium genus. It may also be Bot Canker which is caused by a fungus in the Botryosphearia genus. In either case, is probably not curable, but may be treated as follows:
- Prune out all dead limbs.
a. Back to the main stem if the entire limb is brown.
b. Back to green tissue if only part of the limb is brown. Make sure you prune back into the green wood to make sure you are below the infection.
2. Inject the trees with a phosphorous acid fungicide. This sometimes helps the tree overcome the infection.? this has to be done by an Arborist. Tree Shepherds provides this service using the ArborJet injection equipment.
3. Water the areas around the trees deeply, but not often in the absence of rain. Don’t water them more than once per week and when you do soak the soil deeply. If you never water them, they will be fine (even in drought years like 2011).
4. Try to make sure that irrigation spray does not get on the foliage
5. Pull mulch away from the base of the trees
6. Uncover the root flares
7. Remove support stakes and straps, if the trees are stable enough for that
I recommend that Italian Cypress continue to be planted in our area as they are a great landscaping plant for certain applications. However, the installer must know the cultural requirements of the tree and plant them accordingly.