Birds

Q&A: What’s causing a line of holes on my tree trunk?

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Q: A couple of my mature trees have developed holes in their bark over the years. Interestingly, they’re in a fairly even pattern, running up and down or horizontally across the trunk. Do you know what’s causing it and should I take any action?

A: This sounds like damage from a woodpecker, the Yellow-bellied Sapsucker. The evenness of their drilling pattern is characteristic of this species. They spend the winter in Maryland but breed further north in the summer (and in westernmost MD). Although a tree might eventually succumb to heavy damage, often their pecking causes no serious dieback.

yellow-bellied sap sucker bird on a tree trunk
Yellow-bellied Sapsucker. Photo: Pixabay

They create small circular pits or larger rectangular patch “wells” in the bark to access the sugary sap flow. Insects attracted to the oozing sap are also eaten. They favor forest-edge habitat, plentiful in suburbia, where there tend to be faster-growing young trees. Hundreds of tree and shrub species can be used, but birds prefer those with high sugar content in the sap or those that are ailing or already wounded from prior pest, disease, lightning, or storm damage (and possibly excessive pruning).

sapsucker holes in a tree trunk
Photo: University of Maryland Extension

You may be surprised to learn who else takes advantage of sapsucker activity. Northbound migrants of Ruby-throated Hummingbirds depend on these sap wells as an early source of nourishment before spring blooms are available. Porcupines (Western MD) and bats also utilize them, plus squirrels and several other bird species. Their chiseling, while perhaps inconvenient to us, is therefore invaluable to forest biodiversity. You can learn more about sapsuckers in Cornell’s All About Birds web database.

If you don’t appreciate their drilling on your garden plants, well…there’s little you can do. As a migratory, nongame bird, they’re protected from harm by the Federal Migratory Bird Treaty Act. You could exclude them by caging tree trunks that are being targeted, but this will simply force the birds to choose additional hosts in the area. Plus, it would be difficult to mount and secure such a barrier around a section of trunk with multiple branches. Don’t treat the trunk wounds with any sort of sealant, as that may hinder any healing that does occur. If any branches die back, just trim them off.

By Miri Talabac, Horticulturist, University of Maryland Extension Home & Garden Information Center. Miri writes the Garden Q&A for The Baltimore Sun. Read additional articles by Miri.

Have a plant or insect question? The University of Maryland Extension has answers! Send your questions and photos to Ask Extension.

Q&A: Can you recommend plants that provide food for birds?

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Cedar Waxwing dining on a Green Hawthorn berry. Photo: Miri Talabac

Q: This summer’s mysterious bird illness has me thinking…I’ve become more interested in birds during the past two years and would like to attract them to my yard with plants. Are there favored recommendations?

A: Bird-attracting landscaping definitely beats out bird feeders as the preferable way to bring these beauties into yards for easier viewing as a safer environment than a communal feeder. (While you’re at it, look into ways to discourage window strikes since plants, like feeders, could increase encounters with glass.)

Plant recommendations are going to be incredibly varied because the diet of birds is so varied, both across species and throughout the year. Site conditions in your garden will narrow down what may be an overwhelming list of choices. Here are some general tips:

  • Plant as much variety for which you have room.
  • Plant to provide food for insects and the birds will follow.
  • When looking at berry or seed production, consider productivity for each season.
  • Try to focus on native plants only, since birds will deposit their seeds beyond your landscape.

To pick a timely category – late-ripening berries – there are some notably popular species. Highly-ranked contenders for both resident and southbound migrant birds include Viburnums, Dogwoods (trees and shrubs), Spicebush, Virginia Creeper, Eastern Redcedar, Magnolia, Black Tupelo, Hackberry, Sassafras, Bayberry, Sumac, Hollies, and Hawthorn.

Viburnum nudum
Smooth Witherod Viburnum (Viburnum nudum)
Parthenocissus quinquefolia blue berries
Virginia Creeper (Parthenocissus quinquefolia)
Cornus racemosa white berries
Gray Dogwood (Cornus racemosa)
Winterberry Holly (Ilex verticillata)
A variety of berry-producing shrubs for birds. Photos: Miri Talabac

Cornell’s All About Birds web library plus local Audubon Societies are good resources for more thorough information on individual species diet, habitat preferences, and plant suggestions for both foraging and nesting.

By Miri Talabac, Horticulturist, University of Maryland Extension Home & Garden Information Center. Miri writes the Garden Q&A for The Baltimore Sun.

Have a plant or insect question? University of Maryland Extension has answers! Send your questions and photos to Ask Extension.

Berries, birds, and cicadas in 2021

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For me, at least, it’s been a bumper year for berries.

Black raspberries in my garden in mid-June

In some years, I harvest only sparsely from the various fruit plantings in my landscape. Black raspberries, in particular, get snatched by birds before I can get to them. Not this year. I had them all to myself until this week, and they’re now pretty much done anyway. My guess—and I haven’t seen any science to back this up, but it makes sense—is that the birds have been too busy scarfing down cicadas to bother with berries. Now that the cicadas are gone, they may turn their attention to my fruit-bearing bushes, but I’ve had a head start.

Periodical cicadas are not an unqualified blessing for fruit growers, of course. Female cicadas lay their eggs in branches of a certain diameter, which are abundant on a lot of fruiting plants. This can cause dieback at the ends of these branches. The affected branch tips will fall off naturally over time; you can prune them if they bother you, but remember that cicada eggs are inside slits in the branches, and won’t hatch until probably August. I’m just going to leave mine alone.

Below you can see dieback on blueberry and pawpaw plants caused by cicada laying.

I didn’t bother covering most of my fruit plants, but here in Germantown we didn’t have a huge number of cicadas, either, so the damage has been minimal and the plants will recover. Some growers used netting to keep the bugs out, which is of course really inconvenient if the plants fruit during the same period. I was startled a number of times while harvesting when I moved a branch and suddenly encountered staring red eyes. The cicadas found my blueberries early on, as you can see by this nymph exoskeleton still clinging to a berry that ripened underneath it.

But they are not competition for the fruit itself, and since the birds have been ignoring the berries for the most part, my freezer is full of blueberries, black raspberries, and blackcurrants. I’ve made blueberry chutney, blueberry syrup, and blueberry-lavender shrub (from this book). Shrubs are refreshing drinks made from fruit, sugar, and vinegar, ready in a week or less to be enjoyed mixed with sparkling water or in various alcoholic and nonalcoholic blends. I have plans for jam, cassis and other alcoholic infusions, baked goods, and more.

Fruit-bearing shrubs and trees fit into a home landscape very well. Raspberries and blueberries are great starter plants; I also recommend currants for a shadier spot, though you will not be eating them fresh off the plant, so add in some processing time in addition to harvesting time. (Also be sure that you buy varieties resistant to white pine blister rust, for which the currant family is a host.) Pawpaws are wonderful native trees that add dramatic flair to a landscape; you need at least two genetically-different trees for cross-pollination. They will take several years to start bearing, depending on the size of the trees you plant, and mature trees do sucker prolifically, so you will end up with a pawpaw grove that needs some maintenance to keep under control. But the fruit is not commonly available for sale commercially, and it has a great banana-mango flavor that’s unusual in our temperate climate. You can also try blackberries, gooseberries, and figs. All of these are easier to grow in our climate than tree fruits like apples, peaches, and pears, but if you like a challenge, those are possibilities as well. You can find advice on all sorts of fruit growing on the HGIC website.

I’m wondering how next year will go in my fruit-growing adventure. All these cicada-stuffed birds are laying more eggs and raising more youngsters this year, so the population will be higher in 2022, and there won’t be any periodical cicadas to fill their bellies. So I expect I’ll have to be more vigilant about protecting the plants I can protect in order to have much of a harvest. But I’ll probably still have some leftover blueberries in the freezer, and plenty of jars of jam and chutney. Every year is different in gardening, and 2021 will definitely stand out in my memory for noisy cicadas, happy birds, and plentiful berries.

By Erica Smith, Montgomery County Master Gardener. Read more posts by Erica.

Kent’s blueberry cage

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a row of blueberry shrubs protected by homemade cages

Some people like to keep birds in cages. Kent Phillips, a Master Gardener in Howard County, likes to keep birds out of his cage.

Each June, Kent and two helpers assemble a 10’ high by 10’ wide by 60’ long cage around his blueberry patch so the Phillips family, not neighborhood birds, will feast on the 16 to 20 gallons of fruit that his nine high bush blueberry bushes produce from early June into early August.

kent with blueberries

The uprights of the cage consist of 10-foot lengths of ¾-inch PVC pipe. Each upright is strengthened by a 10’ piece of rebar. Cross-supports at the top link everything together with a system of PVC T’s and L’s. Some are glued permanently, while others aren’t, to facilitate assembling the cage in spring and taking it down in the fall. He pounds a 3-foot piece of one-inch iron pipe into the ground to make 12” to 18” holes into which he slips the PVC/rebar uprights. He then wraps the huge, rectangular PVC box in plastic bird netting.

“I started out 20 years ago with a wooden structure,” Kent explained, “but that was frustrating because the bird netting snagged on every splinter. After a couple of years, I switched to PVC pipe. I use plastic ties to attach the netting to the PVC pipes.”

Kent estimated it takes about 2 ½ hours to put up the structure. “But all the work is worth it,” he said. “I have six varieties of early, mid-season, and late blueberries that produce over 6 to 7 weeks. Harvest depends somewhat on the weather.”

Kent listed three important factors to keep in mind when raising blueberries—pH of the soil, water, and the every-hungry birds.

a handful of blueberries

“The cage takes care of the birds, of course” he said. “My drip irrigation system takes about 3 hours a week to put down an inch of water, without which the berries would be stunted and production would fall. The Home and Garden Information Center has outlined a program using ferrous sulfate and elemental sulfur to keep the pH of the soil between 4.5 and 5.5, the range for maximum fruiting.

“We’ve been picking since early June,” Kent added. “This morning my grandson and my two daughters picked a couple of gallons and cleaned me out.”

What does his family do with up to 20 gallons of blueberries?

“We eat about half fresh and freeze the rest for later use,” he said with a smile. “Our wintertime favorites are blueberry muffins, blueberry pancakes, and blueberry buckle. They’re hard to beat.”

“I’m sure,” I replied, salivating at the thought.