Fall garden Q&A: Keeping out pests, pruning trees and lots of lawn care advice

Washington Post Gardening columnist Adrian Higgins answered questions recently in an online chat. Here is an edited excerpt.

Q: What can the home gardener do about clover taking over a lawn? Last year, I fought crabgrass, and this year, it’s clover. Crabgrass was easier to pick out by hand. Any easier, earth-friendly remedies?

A: Clover isn’t so much a weed as a state of mind. If you come to regard it as a desirable component of the lawn, you won’t have to keep fighting it. Yes, there are herbicides that work against it, but it actually feeds nitrogen into the soil, is an important nectar source for pollinators and only gets expansive when the lawn is allowed to thin. Live with it, but push it back by overseeding the lawn.

Q: What is the best time to prune trees (suckers from plum trees and extraneous branches from a Japanese maple in a pot)? And must the cuts be treated with anything after pruning?

A: Most pruning of deciduous plants is best done during winter dormancy, not least because you can see the structure of the tree or shrub much better then. Other good times to prune are after the flush of spring growth and also right after flowering, so that you don’t affect bud set for the following season. One of the worst times for pruning is over the next few weeks, when cutting back could induce fresh new growth that will be susceptible to frost damage. Wound treatments are no longer recommended.

Q: I have about 40 Knock Out roses. Some have branches that look stressed: lighter green leaves and rust-colored spots. What can I do to address this? And on a related note, would this be a good time to fertilize the roses?

A: I have reached a point where I can’t look at another Knock Out rose. If you enjoy this overplanted magenta flowering shrub, more power to you. You might lay a modest top dressing of rose feed to keep its floral cycles going through the fall. This variety is prone to rose rosette disease, spread by mites. Remove infected plants to curtail its spread.

Q: This August, crabgrass has taken over my lawn. What steps can I take now to minimize the problem next year?

A: Crabgrass is a direct result of lawns that are too thin. Thick, lush lawns are your best bet against weed infiltration. Crabgrass is an annual, so you can either spot-treat or simply hoe them now, but you will have to renovate the lawn to address the problem. Count on using a pre-emergent herbicide in early spring with follow-up applications.

Q: I have a 25-by-25-foot community garden plot that I have divided into quarters, and I rotate my beds each year for a four-year rotation. But for a garden that small, is rotation actually beneficial?

A: Rotation is desirable but almost impossible in such a small garden. I would move varieties around as best you can, but if you see

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Century-old trees, historic graves in gothic revival churchyard :: WRAL.com

— Tucked away in the small North Carolina town of Tarboro is an ethereal place that can only be described as a ‘secret garden.’

Enclosed in a gothic-style churchyard, the ground and graves alike are cloaked in ivy. Century-old trees, crooked with age, create a green dome that, in some places, blocks the sky.

The Calvary Episcopal Churchyard serves as a cemetery, but it is also one of the state’s most beautiful arboretums, with trees and plants from across the globe.

Calvary Episcopal Church in Tarboro has North Carolina's version of a ‘secret garden,’ enclosed in a gothic-style churchyard, cloaked in ivy, with century-old trees from across the globe.

The design of the churchyard and its original plantings are the work of Joseph Blount Cheshire, who served as rector of the church from 1842 to 1889 – meaning some of these trees could be around 150 years old.

Older still is the parish itself, which dates back to before the Revolutionary War and the founding of America itself – harboring records and stories from when the early North Carolina colonists first settled Tarboro in their search for religious freedom outside of England.

In short, there are very few places in the state that date back as far as the Calvary Parish.

Calvary Episcopal Church in Tarboro has North Carolina's version of a ‘secret garden,’ enclosed in a gothic-style churchyard, cloaked in ivy, with century-old trees from across the globe.

North Carolina churches before the Revolutionary War

According to their written history, “The establishment of Calvary Parish dates to 1742.”

During the 1700s and early 1800s, many NC churches met in “brush arbors,” which were essentially shelters surrounded in thick foliage with a wooden frame and perhaps a few benches.

Calvary Parish, however, met in a small wooden building near modern-day Chapel Springs, about eight miles away from present-day Tarboro.

During that time, George II was the King of England, and North Carolina was still an English colony, presided over by a royal governor.

The rector of the parish was named Rev. James Moir. “He reported directly to the Bishop of London,” according to the written history.

Calvary Episcopal Church in Tarboro has North Carolina's version of a ‘secret garden,’ enclosed in a gothic-style churchyard, cloaked in ivy, with century-old trees from across the globe.

The small wooden church was built in 1747, but by 1760 it had burned down, causing the small congregation to move into Tarborough – as it was then spelled.

After the American Revolution, however, the church’s methods of worship, which required a reigning British monarch, were considered treasonous. As a result, the parish changed its name and asked to form into an Episcopal congregation and be accepted into the union with the Diocese of North Carolina. Because of this, the church considers the date of its founding to be 1833, although it actually goes back much farther.

Construction on the building that stands today began in 1858.

Calvary Episcopal Church in Tarboro has North Carolina's version of a ‘secret garden,’ enclosed in a gothic-style churchyard, cloaked in ivy, with century-old trees from across the globe.

Creating a ‘secret garden’ and global arboretum

With many graveyards and cemeteries being wide open, the enclosed churchyard, encircled by antique walls, make it feel like a walk through an old English churchyard, rather than one in small-town North Carolina.

The gothic-revival style of the church building, with grand stained glass windows and gothic archways, creates an ethereal contract with the ancient trees and creeping ivy.

Calvary Episcopal Church in Tarboro has North Carolina's version of a ‘secret garden,’ enclosed in a gothic-style churchyard, cloaked in ivy, with century-old trees from across the globe.

Many of the graves date back to the 1800s, with intricate carvings and designs. The headstones themselves are each

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Lightning can be bad news for trees

According to the United States Precision Lightning Network (USPLN), Florida receives 33 lightning strikes per square mile each year. In the last two weeks we have gotten dozens of calls about lightning-struck trees at the Duval Extension Office. The recent storms seem more severe.

Just because your tree is struck by lightning does not mean it needs to be removed. However, patience will be needed.

Lightning is formed when negative-charged ions collect in a cloud. At the same time, positive-charged ions are forming on the ground under the cloud and following it. As the positive charges build under the cloud, they follow the contour of the ground. If they travel up a tree or another tall object, it may put them close enough for the electric charges to make contact. When that occurs, lightning is formed.

Lightning can injure a tree in many ways. Most ​of the time the damage is obvious. The heat from​ the lightning vaporizes the water in the tree, turning it into​ steam instantaneously. The resulting pressure from the rapidly expanding hot steam blows the wood of the tree apart. Most of the​ time this happens toward the outside of the tree​ and we see it as a streak down the bark. Sometimes​ the damage is not so obvious. We may not see the damage because it has affected​ the root system or the interior of the tree. ​The other thing to think about is that lightning is never the same. A tree can receive a minor strike, a major one, or hundreds of variations in between.  

Treating trees

Lightning strike treatment in trees comes in two phases.​ First, take care of any hazardous situations such as​ broken or hanging branches. Then comes the hard part. The true extent of damage to the tree is not immediately evident right after the strike because lightning comes in an infinite range of voltages and temperatures. We should wait a few months to do any major corrective work. By that time, most of the serious damage will​ be apparent and a decision can be made as to​ whether the tree can/should be salvaged. In the​ meantime, timely irrigation and light fertilization is​ helpful in helping the tree compartmentalize the​ damage.

It may be advisable to install lightning protection in a tree in certain situations — when a tree is a historic landmark, a specimen or in places where people congregate such as a golf course. Lightning protection systems use large copper cables that are installed high in the tree, down the trunk and into a trench in the ground away from the tree, where the cable is connected to a ground rod. This protects the tree and the people around it by giving the electrical charge a better conduit to the ground than through the tree.  Lightning protection systems can be installed by ISA certified arborists and must meet the standards of the Lightning Protection and Grounding Institute or the National Fire Protection

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Taking care of trees in Northeast Florida

Larry Figart
 |  For the Times-Union

Sometimes we take trees for granted. We see them as the pillars in our landscape and sometimes forget that they are living things that need the same conditions to live and thrive as our favorite flower, shrub or groundcover.

Often, we think because they are larger and live longer, they do not need as much care, or they are more tolerant of neglect. In some cases, this is true. A leaf disease that would doom our prized rose is barely a minor nuisance to a maple tree.

However, the origin of most landscape tree decline, and eventual death can be traced back to something that was done in the past (sometimes years) by someone not knowing that it would harm the tree. In the horticultural world, these practices that cause tree decline are called cultural causes and most of the time can be avoided.

Let’s explore some of the most common cultural decline causes and how to avoid them.

Giving trees enough space: I recently drove through a new subdivision. The developers had planted live oaks about 2 feet from the edge of the curb, in between the street and the sidewalk. I am sure the intention was that some day the trees would be part of a beautiful street tree canopy. It would have been better to plant the live oaks in the middle of the yard where they had plenty of space or plant a smaller tree in the space between the sidewalk and the street.

Before you plant a tree do some quick measurements to see how much room you have. A small maturing tree with less than a 20-foot crown spread needs about 200 square feet of space. A medium-sized maturing tree with a 30-foot crown spread needs 400-500 square feet of rooting space. A large maturing tree needs a minimum of 900 square feet of rooting space.

Planting too deep: The number one cause of tree decline for a young tree is the practice of planting too deep. If you look at trees in natural areas such as parks, you will notice that the part of the trunk where the roots flare out from the trunk is above ground. This zone where the roots begin is called the root flare. When we plant a tree the root flare should be visible and located slightly above the soil grade. If you take a look at the base of your tree and it looks like a fence post in the ground, it is more than likely planted too deep. A wise forester once told me, “Plant it high and it won’t die.”

Deep planting is a mistake performed by homeowners and landscape professionals alike. Deep planting encourages roots that will choke the trunk of the tree, as well as encourages disease and decay at the base of the tree by prolonging the time the trunk stays wet after rainfall or irrigation. It also reduces the amount of oxygen that tree roots

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