Cypress turning brown

Question

I bought what I believe to be a lemon cypress, also known as goldcrest or Cupressus macrocarpa, a few months ago. I planted it in a fairly large vase, and for the first two months it seemed happy, receiving light in the afternoon but not the morning and receiving very little water, only when it rained.

Eventually I had to move it from my front yard to my backyard, where it ended up receiving light the whole day: it then started turning brown. I then moved the vase to another part of my backyard, where it receives a little light in the morning and none the rest of the day. I started watering it more frequently, thinking it needed extra water because of the extremely hot whether these last few weeks, at times over 30°C. But it continued turning brown, and now I'm not exactly sure of what's happening. Why is my cypress turning brown? Am I watering it too much, too little, does it need more light? This question here is not very helpful, that plant is rather smaller, and I did not use fertilizers.

EDIT: After @Cheshire_the_Maomao's answer I tried to look really close into the brown leaves to find something like they describe, but to no avail. I noticed, however, that these leaves feel really dry to the touch: could it be that I found a really, really parched cypress? Should I try watering it abundantly for a week, or will that definitely kill it?

Answer 1

Yes, its symptom is different from the other question you cited. Notice on your tree, a branch wither as a whole, and in that question leaves wither partly from top.

I think there are 2 possibility. Most common is 侧柏叶枯病, literally leaf-withering disease, I can't find its English name. It says

Black particles are produced on dead scale leaves and twigs, which absorb water and swell into olive-colored cups in humid weather, which is the ascomycete disc of the disease.

Maybe you can take a closer look.

Also it is possible to be longicorns larvae. You can chop the dead branch down and see whether there are any worms in them.

You may be watering too much for a cypress - cypresses are resistant to drought. But I think that may not be the largest problem nor the sole reason why it withers.

Answer 2

I maintained a number of Cupressus for years. They are lovely plants but very specific in what they like. The maintenance that worked for us was:

• strong diffuse light, not a hot exposure in the south or west
• daily misting with distilled or filtered water
• watering every few days
• clay pots to retain moisture and act as a counterweight for these plants which can become quite tall

I suggest the following:

• cut back the dead foliage. It's not coming back.
• remove the stones on top of the soil. They make it hard to determine how dry the plant is
• water according to the season, less in the winter, more in the spring. Hot dry weather in summer is a challenge for these plants. Is a more humid location with air movement possible?