Crapemyrtle woes

An infestation of Crapemyrtle Bark Scale on a crapemyrtle trunk. Sooty mold is darkening some of the outer bark layers. Photo: Jim Robbins, Univ. of Ark. CES, Bugwood.org

Q:  My crapemyrtle has white stuff on the bark that I’ve never noticed before, though the foliage looks unaffected, if a bit dull lately. I thought these plants were pretty pest-free, so what might this be?

A:  We’ve had a lot of inquiries about this lately. Your plant has Crapemyrtle Bark Scale (CMBS), a non-native insect pest that was discovered in Texas in 2004 and confirmed in Maryland in 2020. Incidentally, crapemyrtles also can host Crapemyrtle Aphid, and it’s possible for the two to be infesting a plant simultaneously; their impacts on the plant are similar.

While CMBS could potentially feed on other host plants, so far they seem to strongly prefer crapemyrtle. The aphid sticks to crapemyrtle. Both secrete honeydew, the sugar-water waste common to sap-feeding insects, which is dulling the leaf appearance and probably cultivating a bit of sooty mold.

Since mid-Atlantic gardeners have embraced crapemyrtle to such an extreme that it’s everywhere you look, that’s a big buffet enabling this pest proliferation. We really need to diversify our landscapes.

Scale insects lead relatively sedentary lives, generally only moving about to any notable degree as newborns, appropriately called crawlers. After roaming to find a feeding site, crawlers settle down and stay put, using their straw-like mouthparts to feed on plant juices. Layers of protective wax, in this case felt-like and white, cover their bodies as they mature. For our purposes, this also means they are harder to treat with contact-type insecticides like oils or soaps because that shell prevents the pesticide from reaching them. Crawlers, running around shell-less for that brief window of time, are the most vulnerable life stage any treatment should focus on.

The problem is, this pest is so new to our area that we are still collecting data on when those crawlers appear. Insect development is dependent on temperature, so while we can make predictions based on how CMBS behaves to our south, we’re still refining our knowledge for Maryland. Complicating matters is the likelihood of several generations per year, and they might overlap.

For such a tiny thing with limited mobility, you may wonder how it got there in the first place. Like plant mites, crawlers can blow around on the wind, and might also disperse by hitching a ride on other animals, like birds. CMBS arrived in our area the way many plant pests do – accidental introduction on plants with undetected infestations shipped-in from out of the area.

Management of an established scale population, usually booming by the time we notice them, takes time. Don’t expect one or two treatments to resolve the issue quickly, and you’ll probably need to employ the services of a certified pesticide applicator. Manually scrubbing scale off while not wounding bark is difficult and not highly effective, given the nooks and crannies they can wedge themselves into that you cannot reach.

Not only should certified applicators treat trees too high to reach, but they will have more effective equipment and the ability to apply chemicals the general public cannot due to the Maryland pollinator protection law. Overlapping the use of more than one type of pesticide may be needed, and re-treatment might occur for over a year. Dead scale won’t fall off right away, though treatments for scale will probably suppress aphids at the same time.

While we usually suggest trying other methods to suppress pests, once scale are numerous, there is little recourse than resorting to pesticide treatment. Certain species of lady beetle larvae will consume these scale and could knock-down their numbers somewhat, so avoiding contact-type pesticide use or enthusiastic scale-squishing attempts does at least spare them. Drastically cutting back a large crapemyrtle is not recommended since that can ruin its branching structure, though you could try it with dwarf shrubby varieties since otherwise-healthy plants should regrow over future seasons. With proper application timing to avoid impacts on scale predators and other insects (something well-trained pesticide applicators and pest scouts know how to do), treatments can be done with minimal risk to the biodiversity in your landscape. Or…just plant something different and rely on other plant species to provide summer color.

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

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

Fall Colors: The Garden Thyme Podcast

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Fall is almost here, and we are ready. Nothing signals the start of fall like the changing of the leaves. In this episode, we discuss what causes the leaves to change color. It was also really hard to choose, but we picked our top 5 trees with the best fall color.  We also have some suggestions for shrubs, grasses, and flowers that make great additions to the garden in the fall. 

We also have our: 

  • Native Plant of the Month – New England Aster ( ~37:22 )
  • Bug of the Month – Paper wasps (~41:30)
  • Garden Tips of the Month  (~49:15)

The Garden Thyme Podcast is brought to you by the University of Maryland Extension. Hosts are Mikaela Boley- Senior Agent Associate (Talbot County) for Horticulture, Rachel Rhodes- Agent Associate for Horticulture (Queen Anne’s County), and Emily Zobel-Senior Agent Associate for Agriculture (Dorchester County).

Theme Song: By Jason Inc

Brighten your garden with fall-blooming perennials

Mum’s the word. Or is it?

Chrysanthemums are ubiquitous, popping up in gardens, on doorsteps, by mailboxes and storefronts, a sure sign of fall.  

I have a soft spot for the tumble of peach-toned blooms that are Sheffield mums. Naughty kids that bumble over other blooms in rowdy heaps, they are gorgeous and reliably hardy, unlike many other mums. But why limit yourself – and your garden – to mums? Many other perennials jazz up the fall garden, adding delicious colors, textures, and scents.

Aptly named by Carl Linnaeus after the Latin word for “star,” asters boast abundant daisy-like flowers in pink, purple, blue, or white. Ranging from one to six feet tall, they fit every garden. Two-foot ‘Purple Dome’ needs no staking, but taller varieties such as the striking native New England aster need support to avoid the dreaded flop. 

I have a thing for anemones. Their delicate flowers dance in the slightest breeze. Single or double blooms in white, pink, or lavender float on tall stems like leggy chorus girls. Also attractive are anemone’s seed heads: fluffy cotton balls sprinkled with seeds. Kids love to play with them. Me, too. 

Goldenrods stretch their arms through gardens in late summer and fall, adding a flash of gold. Tall airy types abound as do compact cultivars such as ‘Golden Fleece.’ Ten native goldenrods thrive here.

Scoliid wasp on chives

The garlic chives in our demonstration garden are going bonkers, their white pom-poms bustling with pollinators. A clump-forming perennial herb, its flowers and leaves are edible.

Garlic chives produce abundant seeds, so be ruthless in cutting off their flower heads before they go to seed. And yes, you can get your jollies by shouting, “Off with their heads!” My apologies to Lewis Carroll. 

Call them commoners, but native black-eyed Susans are tough broads that look good in fall. Their golden blooms surround a dark “eye” that fills with seeds to feed birds and other wildlife. 

Maryland’s state flowers, they are often marked “vigorous” on plant tags, meaning they tend to spread. So place them carefully with other robust plants or let them go unbridled in a wilder area.  

Leave black-eyed Susans’ stems standing to add winter interest. In fact, leave all of your perennials standing except those that had serious disease or insect issues or are spreading beyond reason.  

Why? Beneficial insects overwinter in their stems and under fallen leaves. Their seeds provide food for wildlife and their structure offers cover. So wait to cut perennials back until spring.  

Fall is here. I hope I’ve inspired you to look beyond mums to rev up the color, impact, and wildlife value of your fall garden.    

By Annette Cormany, Principal Agent Associate and Master Gardener Coordinator, Washington County, University of Maryland Extension. This article was previously published by Herald-Mail Media. Read more by Annette.

This article was previously published by Herald-Mail Media.

Having an off year in the vegetable garden. Highlights and lowlights

Over the previous two summer growing seasons, I have blogged about my non-expert experiences building and growing my vegetable garden while attempting to put into practice a lot of things I’ve learned via osmosis working here at the Home and Garden Information Center (view past posts I’ve written to see my progress).

I didn’t write about my exploits during this year’s season since my ambitions were not particularly great or new, as I expected we would be too busy with our baby to put more than a large amount of effort into the garden. My wife started some seeds last year, but was too busy to do so this year, and we wanted to have a permanent rodent fence and gate, so that building project bumped back my direct-sowing and planting schedule.

The year turned out to have more lowlights than highlights, but put all together in one blog post here, I think there’s enough to provide some interest and learning.

Highlight: permanent garden fence and gate constructed

If you’ve tracked my blog posts over the last few years, you’ve seen me go from two store-bought raised beds stuck in the middle of the yard, to what I’ve built now: 3 total beds (one built from scratch), a gravel surrounding space, hand-crafted collapsible trellis and tomato support, and new for this season, a permanent rodent fence with gate.

Gravel garden area with wood fence
New, more secure and better-looking wood fence.

Our previous fencing, which I took down each season, was just garden stakes with wire fencing around the perimeter of our gravel area. This type of fence allowed a lot of grass to grow into the inside of the area via the base of the fence, making things look sloppy. The construction of the wood fence fixed the junction of the wire fence to our gravel base border, eliminating this problem, and making the whole garden look more like a designed, permanent fixture, rather than something sloppily put together.

I’m happy to report that we had 0 notable creature infractions in our garden since the permanent fence has gone up!

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Cover crops for climate-resilient soil: Try it, you might like it

Cover crops are so important for improving soil and protecting the environment that it’s public policy in Maryland to use federal funding to subsidize farmers to plant them. Nearly ½ a million acres across the state are enrolled in Maryland’s Cover Crop Program. Cover crops protect Maryland’s farm fields from soil loss over the winter and scavenge the soil for the fertilizer nutrients that weren’t used by corn and soybean crops and might have moved into groundwater and surface water. 

Cover crops are typically planted from late August through October and include grasses like winter rye, winter wheat, barley, and oats and legumes like crimson clover and hairy vetch. Plants in the legume family, together with special soil bacteria, transform nitrogen from air into a plant-available form. Tillage radish (a type of daikon radish) and other plants are also grown as cover crops. 

Cover crops improve soil health and help make soils more resilient to the climate crisis. They

  • increase soil organic matter and carbon sequestration by feeding soil microbes with sugars and other root exudates 
  • improve soil structure and the strength of soil aggregates which lowers erosion risks
  • increase water holding capacity which allows crops to withstand drought better   

Cover crops use the sun’s energy (when food crops aren’t growing) to produce biomass- roots, shoots, and leaves. The cover crops are killed in the spring. Nutrients in the decomposing plants are eventually available for uptake by the roots of the vegetables and flowers we plant. This reduces the need for synthetic fertilizers, whose production requires fossil fuels.

What’s good for ag soils is also good for garden soils! 2022 is the Year of Soil Health for Grow It Eat It, the food gardening program of the UME Master Gardener program. This infographic by Jean Burchfield introduces the idea of planting cover crops, a key practice in building healthy soils: 

Infographic about cover crops

Photo of seed packets
UME Master Gardeners distributed 5,000 crimson clover seed packets for residents to plant in flower and vegetable beds this fall.
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Goldenrods & asters: Important fall flowers for pollinators

With the fall very clearly upon us, we tend to think more about falling leaves than flowers. Indeed, the big flower boom is ending, with all early-season flowers well past flowering. However, fall is a very important season for many pollinators, which still require food and shelter in preparation for the winter. In this blog, I would like to take a little bit of time to go over the importance of fall resources for pollinators, and what you can do to make sure they are available in your green spaces.

Why is fall special in nature?

The end of summer/fall is a special time for many organisms in our temperate regions. This is usually the last chance these organisms have to gather energy and resources to get ready for the winter. In the case of pollinators that are active during this period, the fall is key for collecting sufficient pollen (=food) for their nests, and for finding appropriate overwintering spaces for the adults and/or the offspring (take a look at this post to learn more about this), all of which will impact survival until the following year/season. If we want to help these pollinators, making sure that these resources are available is the best we can do!

Providing food for pollinators in the fall

Several native plants in our area flower in the fall and act as wonderful resources of pollen and nectar (and more!) for our late-summer/fall pollinators. These plants are easy to grow and once established provide abundant (nutritional) resources for our local insects.

Goldenrods

This group (Solidago spp.) consists of many species which flower in the late summer/fall. These plants are perennials that will create patches once established in an area. For this reason, they are easy to grow, although for this very same reason may usually require a bit of containment, since otherwise, they will easily spread everywhere. If the latter is a problem, plants can be grown in pots, where the containment issue is more easily resolved.

These plants support a large community of many different types of bees (many of which are specialists that can use only specific types of pollen and can be rare), as well as butterflies, flies, and wasps. In fact, more than any other herbaceous plant studied by Fowler/Droege, goldenrod (species in the genus Solidago) supported the most specialist bees (39 species). Importantly, because these plants create tall hollow stems, they can also act as nesting resources for stem-nesting bees. This way, these plants are great fall resources for many of our pollinators.

flowering goldenrod mixed with other asteraceae flowers
Goldenrods develop numerous flowers that provide support to a very large number and diversity of pollinators. In this picture, goldenrods stand out of a background of other yellow Asteraceae in a home garden. Photo: A. Espíndola

Two easy-to-grow species that one can find in several native nurseries are the tall goldenrod (Solidago altissima) and Canada goldenrod (Solidago canadensis). Both species have long stems that end with many yellow inflorescences. Both of them flower in the late summer and fall and can be easily grown in green spaces, especially drier sites that are exposed to the sun. As said before, although these plants are great pollinator magnets and resources, they tend to spread readily, so, unless that is wanted, they require some control once they start spreading in an area.

Asters

Asters are another group of plants native to our region that acts as a great pollinator resource in the fall. These plants are also perennials and can be small or become shrub-like, depending on the species. Unlike the goldenrods we were talking about just above, these plants tend to display a larger variety of floral coloration, with flowers going from white, to pink, and purple, depending on the species. Like goldenrods, these plants provide both food and nesting sites to many pollinators. Their flowers attract a very large variety of pollinators (bees, butterflies, flies, beetles, wasps) during a time when there is little else to feed on. The flowers of these plants are also known to support specialist and often rare bees, which depend strongly on its pollen for survival, as well as many butterflies, including Monarchs. Their stems are also great sites for stem-nesting bees. Finally, their leaves support the larvae of many local butterflies.

purple flowers of new england aster and a monarch butterfly
New England asters can be obtained from native plant nurseries and are able to support a very large diversity of pollinators, including rare and specialist bees, as well as adults and larvae of many butterflies. In this picture, we can see a Monarch adult feeding on the characteristic purple/blue flowers. Photo: Glenn Marsh

A lovely species that can be grown in our green spaces and provides hundreds of blue/purple flowers is the New England aster (Symphyotrichum novae-angliae). This perennial herbaceous plant can be obtained from nurseries and will grow three to six feet tall in the summer (but it can be cut back in mid-summer if you want to keep it shorter). The plant requires at least some sun and does well in a variety of soils we find in Maryland. I love watching the lovely cute flowers, and all the activity they attract. This is really one of my personal fall garden highlights!

By Anahí Espíndola, Assistant Professor, Department of Entomology, University of Maryland, College Park. See more posts by Anahí.

Anahí also writes an Extension Blog in Spanish! Check it out here, 
extensionesp.umd.edu, and please share and spread the word to your Spanish-speaking friends and colleagues in Maryland. ¡Bienvenidos a Extensión en Español!

Diggin’ into plant-based diets

As gardeners, one of the many actions we can do at home to mitigate climate change is to grow and eat some of our own fresh produce. Meat and dairy products account for an estimated 14-16% of global greenhouse gas emissions, according to the UN’s Food and Agricultural Organization. Having a home or community garden gives you access to nutritious foods that can be part of a more plant-based diet — one that’s healthy for you, and the planet! Today’s guest post on this topic is from University of Maryland Extension Family & Consumer Sciences Agent Beverly A. Jackey.


Following a plant-based diet is very trendy these days. Whether it’s an environmental reason (reduce your carbon footprint) or a health goal (decrease the risk of some chronic diseases), many people, including myself are consciously reducing their consumption of animal products.

What does it mean to follow a plant-based diet? That really depends. Some interpret it as being a vegan or vegetarian. Others view a plant-based diet as being broader, including more plant foods, such as fruits, vegetables, and grains, and also fewer animal foods, like meat, fish, and dairy. It’s not necessary to give up all the animal foods you enjoy; however, you can consider decreasing the portion sizes so these foods are no longer the main attraction on your plate. 

Ever since attending a 2019 nutrition conference, I’ve been inspired to consume more plant-based foods. It’s unlikely I will give up my glass of cold, fat-free milk in the evening (with one cookie); however, I do consume at least three meatless meals per week, eat smaller portions of chicken, fish, and lean beef and pork, and I load up half of my plate with vegetables (see my grilled vegetable recipe). This summer, my deck garden provided enough delicious red tomatoes to enjoy almost every day on salads. Since making these changes, I’ve maintained a healthy weight and blood pressure and feel good about doing something for Mother Earth. 

Are you ready to ‘dig in’ and adopt a more plant-based diet? Here are some tips that helped me get started.

  1. Go meatless one day a week. Beans, lentils, and nuts are great sources of plant proteins and add fiber to your diet, which makes you feel full. Instead of adding meat to my pasta, I toss it with grilled vegetables. If you like chili, peruse recipe websites for a bean-based chili that appeals to your taste buds.

  2. Combine vegetable proteins. Quinoa is a perfect protein, meaning it contains the 9 essential amino acids your body needs daily. You can also combine other plant foods to get that perfect protein. Some of my favorite combos are black beans and rice, chickpeas and pasta, and whole wheat bread and peanut butter (with some jelly).

  3. Re-think your meat portions. You can still have meat at your meals, but in smaller amounts, like 3 cooked ounces (the size and thickness of a deck of cards). Many meals like soups (winter) and salads (summer) are full of vegetables and whole grains, but I add a small piece of protein, like a leftover grilled and shredded chicken breast or a few slices of pork tenderloin.

Try this recipe for Easy Grilled Vegetables!

Selection of vegetables:

  • Red, yellow, or green peppers – cut in half and seeded
  • Yellow and green squash – sliced length-wise, about ½ inch thick
  • Eggplant – sliced width-wise, about ½ inch thick
  • Mushrooms – whole cleaned
  • Onion – sliced width-wise, about ½ inch thick

Additional ingredients:

  • 1/2 cup olive oil
  • Salt and pepper
  • 4 tablespoons balsamic vinegar
  • 2 teaspoons, minced garlic
  • Fresh chopped or dried herb (parsley, thyme, basil, etc.) for garnish

Instructions:

1. Mix oil, salt, pepper, vinegar, and garlic together.

2. Arrange vegetables on the grill or in a grill pan (medium heat). Note: depending on the size of your pan you may need to work in batches.

3. Grill vegetables for 6-8 minutes, brushing with oil, and vinegar mixture.

4. Remove vegetables from the grill or grill pan and place them on a platter. Drizzle the remaining oil and vinegar mixture on the vegetables. Sprinkle herbs over vegetables and serve.

By Beverly A. Jackey MS, RDN, LDN, Agent, Family & Consumer Sciences, University of Maryland Extension (UME). This article was published originally on the UME Breathing Room blog, which covers topics on health, wellness, nutrition, and financial management.