Italian cypress trees susceptible to spider mite damage in the winter

Q: We have almost a dozen Italian cypress trees in our backyard. They seem to be dying, and it’s getting worse. We thought we saw spider webs on some. What would cause this browning, and what can we do to save them?

THE: Spider mites do attack Italian cypress. They usually start toward the bottoms of the plants and flush upward and outward.

Assuming you have not applied any type of insecticide or miticide, the best way to tell for sure is to thump a branch that is starting to turn brown (but not already brown) over a sheet of white paper. If you can see the ultra-tiny (almost microscopic) specks of reddish-brown starting to move around on the paper after 20 to 30 seconds, those are the spider mites.

The type that attacks cypress and junipers will show up in winter, unlike the ones we see are tomatoes, beans, marigolds and so many other plants in the summer. If you see the mites, spray the plants thoroughly with a general-purpose insecticide. Be careful to penetrate all the branches with the spray.

The browned needles won’t green up again, however. These plants look pretty rough. You may ultimately decide that you need to replace them just to get a better look at your landscape. I’d suggest Oakland holly as an upright shrub that is better suited and more easily maintained.

This avocado tree was sheltered in the freeze, but still suffered damage. Avocadoes do not have much winter heartiness.

Courtesy photo

Q: This is our Lila avocado. I set it in our garage with a heat lamp last February. It survived, although it had no fruit. Now the slit in the trunk has become much worse. Do you think it will make it?

THE: It looks like the trunk and bark are extremely compromised. It appears to be trying to heal, but only time will tell.

Assuming the tree does survive, the pot won’t be large enough as it grows and develops. You’ll need a much larger container. Hopefully it will heal enough to bear for you. Keep it moist at all times and protect it from freezing temperatures. You lose a lot of winter hardness when you have a plant’s root system above ground, and avocados don’t have much hardness in the first place. Good luck with it!

This spring I need to add topsoil and compost to my lawn and aerate the ground. In what order do I do these? Also, I have been advised not to add topsoil. Does compost work like topsoil for filling in where erosion has washed too much soil away?

THE: Let me break that down into three procedures.

First, I don’t recommend aeration of a lawn unless you have extreme compaction, for example, brought on by someone parking on an area for a prolonged period or kids playing football daily and packing down the grass. Aeration is also used when there is a layer of thatch (undecomposed organic matter) on top of the soil and beneath the runners. That’s not to be confused with browned leaf stubble left over from winter freezes. My guess would be that no aeration is likely to be needed.

The same would be true for adding compost. It adds organic matter, but it decays over a year or so and you would be left right where you are today. Compost would be much better used as a soil amendment in flower and vegetable beds where you rework the soil annually.

This hibiscus was left uncovered in the last freeze and is now dead.  They are killed by exposure to freezing weather, especially if it's for more than a few minutes and if it's more than a degree or two below freezing.

This hibiscus was left uncovered in the last freeze and is now dead. They are killed by exposure to freezing weather, especially if it’s for more than a few minutes and if it’s more than a degree or two below freezing.

Courtesy photo

That leaves the topsoil and your need for a remedy for erosion. If you are sure that the soil has actually been washed away, begin by determining the source of the water (runoff, downsprout, etc.) and how you can change its flow patterns. Then, to fill the eroded areas, you may want to dig out the existing sod, put topsoil into the void and replant the sod at the proper grade. That should all be done in late April or May when the grass is growing now actively. It is best to use topsoil from your own property so that it will be a perfect match in terms of moisture-holding ability and fertility.

This Shumard red oak has sun scald.

This Shumard red oak has sun scald.

Courtesy photo

Our red oak was planted by our builder seven years ago. It has done well, but it started to develop this crack (see photo) three years ago. It doesn’t appear to be affecting the tree now, but I’m afraid it might later. What do I need to do?

THE: This is sunscald. I’d be willing to bet that this crack is on the west or south side of the trunk where the sun has hit it broadside. It looks like it’s trying to heal, and the damage is already done, so there isn’t anything you can do from this point on. Hopefully the branches on this side of the trunk will not be adversely affected.

For the record, anytime an oak, maple or Chinese pistachio is planted, it should have the protection of paper tree wrap for the first two or three summers in its new location. That will protect against this kind of damage. Also, you didn’t ask, but if the tree is as far out-of-plumb as the photo suggests, you may never be satisfied with its appearance. The only remedy would be to dig and reset it, and at that point you might be better advised to start with a new tree.

This hibiscus was left uncovered in the last freeze and is now dead.  They are killed by exposure to freezing weather, especially if it's for more than a few minutes and if it's more than a degree or two below freezing.

This hibiscus was left uncovered in the last freeze and is now dead. They are killed by exposure to freezing weather, especially if it’s for more than a few minutes and if it’s more than a degree or two below freezing.

Courtesy photo

Q: You can see the impact of this year’s first freeze in the “before” and “after” photos of our hibiscus plant. We forgot to cover it. Is it lost, or do you think it might come back?

THE: It’s a tropical hibiscus. They are killed by exposure to freezing weather, especially if it’s for more than a few minutes and if it’s more than a degree or two below freezing. There are “hardy hibiscus” types called mallows, but they have a different look entirely. As for this baby, she’s a goner. I’m sorry.

Email questions for Neil Sperry to SAENgardenQA@sperrygardens.com.

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