Michigan Gardener - Your guide Great Lakes gardening: Garden Event Calendar / Expert Advice / Plant Profiles / Tree Care

What is a good choice for a privacy shrub?

February 8, 2021 • Leave a Comment

What is a good choice for a privacy shrub in southwestern Michigan? How early in the spring can I plant it?

When seeking privacy, plant more than one plant. A trio works well as they balance each other, forming a community rather than an “orphan” look. Plant three of one species laid out in a shallow triangle so they fill in around each other aesthetically. Straight rows look artificial. You can also vary the trio with a single specimen for the center point and flank each side with another species.

For example, center a leatherleaf viburnum (Viburnum rhytidophyllum)with its soft, oval, gray-green leaves and flank it with native ninebarks (Physocarpus opulifolius) with burgundy leaves and peeling bark. Both are deciduous in zone 5. Viburnum tops out at about 10 feet and the ninebark tops out about 8 feet. They both bloom spring to early summer, have considerable winter interest, grow relatively quickly, and deer don’t find them appealing.

Another possibility is centering an evergreen such as ‘Green Giant’ arborvitae, which is an open pyramidal evergreen and less appealing to deer. They are tolerant of various soil types, but prefer good drainage. An evergreen paired with deciduous shrubs can get you more “instant” privacy than waiting for three identical shrubs to reach maturity.

Flank the evergreen with the ninebark variety Amber Jubilee which has gold-orange overtones in the leaf veins, or ‘Summer Wine,’ which features a dark burgundy color. By creating a group of compatible plants, spaced apart according to their mature width, you have something attractive to look at while achieving a privacy screen.

Related: Tree and shrub pruning tips

Mountain pine beetle quarantine enacted in Michigan

January 11, 2021 • Leave a Comment

**Damage caused by the Mountain Pine Beetle in British Columbia, Canada. (Photo: Jonhall / Wikipedia)**

The Michigan Department of Agriculture and Rural Development (MDARD) is working to protect Michigan’s pine trees from a potentially devastating pest: the mountain pine beetle. One of the most destructive forest pests in North America, it is known for outbreaks that have killed millions of pine trees in the western United States and Canada.

According to MDARD Director Gary McDowell, “Mountain pine beetle hasn’t been detected in Michigan yet, but we’re taking the necessary, proactive steps to ensure our pine resources are here for generations to come,” said McDowell. The state’s new “Mountain Pine Beetle Exterior State Quarantine” regulates the movement of pine forest products with bark including logs, stumps, branches, lumber and firewood originating from a number of impacted western states.

The beetles affect pine trees by laying eggs under the bark and introducing a blue stain fungus. The joint action of larval feeding and fungal colonization kills the host tree within a few weeks of successful attack. As beetle populations increase, or as more trees become stressed because of drought or other causes, the beetle population may quickly increase and spread.

Mountain pine beetle has expanded its range, moving northward and eastward. The expansion is attributed to warmer winters, which allow more beetles to survive. Michigan’s pine resources are at risk of attack, including white pine, jack pine, red pine, Austrian pine, and Scots pine. Learn more about the quarantine here.

What is causing fruit to drop early on my apple tree?

December 15, 2020 • Leave a Comment

**McIntosh apples on a tree. Photo: George Chernilevsky / Wikimedia Commons**

We have a McIntosh apple tree that is about 30 years old. We have never sprayed it. In the spring, lots of tiny, green apples start falling. The remaining apples are wormy and misshapen, thus we end up composting all of them. Is there anything we can do so the apples are good to eat?

Every McIntosh apple has a direct lineage to a single tree discovered in 1811 by John McIntosh in Dundas County, Ontario. Your 30-year-old McIntosh is a venerable species worthy of treatment.

Premature apple drop can stem from several factors. A tree unable to support the vast number of fruits it has produced naturally thins out the fruit to decrease competition and conserve energy. Environmental conditions such as later frosts, excessive heat and cold, and abrupt changes in humidity can cause fruit to drop. The soil may be nutrient-deficient to support fruit growth. A soil test targeting apple trees is in order. Irregular watering can also cause fruit drop. Examine the weather patterns of the last few years to determine what weather conditions occurred. Consider your watering practices and note changes and improvements.

The condition of your remaining apples suggests a strong pathological source. If there are “worms” in the fruit, you probably have codling moth (Cydia pomonella). The worms are the larval stage of this pest. The second generation adults emerge in July laying eggs on the apples. The young caterpillars can tunnel into the developing fruit shortly after egg hatch, exiting to pupate into another generation moth. This is when the most damage is done.

To get good eating apples again, you need a steady maintenance program of vigilance and treatment. Homeowners can manage watering and fertilizing consistently. You can also practice good yard hygiene by removing fallen leaves, fruit, and debris from the tree’s vicinity. Such plant debris provides opportunities for re-infestation. Through observation in the spring, verify the codling moth is the culprit before embarking on any spray insecticide program. Because of the critical timing of sprays and the chemistry of insecticides, hiring a professional arborist who is experienced in tree fruit culture is a wise move. In the space of one season, you should see a marked improvement in edible fruit.

ALSO READ: Tips for Growing Apples in Michigan

Digital Edition