Question
QUESTION: Dear Experts,

We live in Northern California. There were 10 cypress trees in a row, in the south side of the backyard, along the wood fence as a screen when we moved into this residence. About 3 years ago, the first tree from east end of the row turned yellow, we removed it. 2 months ago, the second tree turned yellow and was removed. Now the fourth tree in the row is turning yellow again. Is it dead, or just sick? Should we also remove it, or rescue it? How to rescue it? How to prevent the rest of the trees from getting sick? Should established cypress trees be watered and fed regularly? Is it the normal life spin for cypress trees? If so, what are the best trees for replacement?

After the first tree removed, we planted an orange tree in that spot 6 months ago, but it didn抰 grow. Is the soil the problem?

Mary

ANSWER: Mary:
If these are bald cypress (Taxodium distinctum) trees, they are commonly found along an area w/a good supply of water like along the side of lakes or streams. Yellowing is often a sign of root and/or soil related issues. This may translate to either a water or nutrient imbalance.  If it has been dry previously, consider supplemental watering.  Consider also having a soil test done. Contact your local nursery/garden center for that information or better yet, your local county agricultural Extension office (see phone book). There are some general fertilizers for trees- agin check with your nursery for this stuff.  Also, take a look at the other cypress trees for any evidences of bark injury on the main trunk, especially near the base.  Depending on the location, trees may indeed need supplemental water (e.g. summertime, hot/dry/windy conditions).  Fertilization, not so much, but if your soil pH (acidity/alkalinity) is off, then the tree may not be able to pick up the right stuff from the soil.

Regards
Steve

---------- FOLLOW-UP ----------

QUESTION: Dear Dr. Stephen Vann,

Thanks so much for your help. They are not bald cypress. They are Italian cypress. We barely water or feed them. We will check the rest of the trees to see if there is any bark damage.

And we also have a boxwood hedge at the northwest side of the garden next to neighbor抯 oleander hedge. Three of the boxwood plant in the middle of the hedge died rescently. We planted new boxwood plants in that spot twice, but never made it. Is it the problem in soil?

Regards,
Mary


Answer
Mary:
Italian cypress do not require much soil moisture as do the bald cypress.  The Italian type prefers well drained soil in fact. Standing water in the roots will cause some big issues.  One thing to be aware of on these are spider mites.  These very small 8 legged critters can cause problems. To check for these, hold a white piece of paper under a yellow twig and tap that twig a few times over the paper.  Look for very very small yellow-red bugs crawling on the white paper.  They usually show up easily with a white background.  Try this on several yellowed twigs. Let me know if you see any.


With the boxwood dying- soil could indeed be an issue. Does that spot stay wet? Maybe send me a photo of this area. Review your image on the computer first- to be sure it is in focus before sending.

Steve